Impact of intermittent preventive treatment with sulphadoxine-pyrimethamine targeting the transmission season on the incidence of clinical malaria in children in Mali

A non-randomized controlled trial to assess the protective effect of SMC in the context of high parasite resistance in Uganda

BACKGROUND

Until recently, due to widespread prevalence of molecular markers associated with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) resistance in east and southern Africa, seasonal malaria chemoprevention (SMC) has not been used at scale in this region. This study assessed the protective effectiveness of monthly administration of SP + AQ (SPAQ) to children aged 3-59 months in Karamoja sub-region, Uganda, where parasite resistance is assumed to be high and malaria transmission is seasonal.

METHODS

A two-arm quasi-experimental, open-label prospective non-randomized control trial (nRCT) was conducted in three districts. In two intervention districts, 85,000 children aged 3-59 months were targeted to receive monthly courses of SMC using SPAQ during the peak transmission season (May to September) 2021. A third district served as a control, where SMC was not implemented. Communities with comparable malaria attack rates were selected from the three districts, and households with at least one SMC-eligible child were purposively selected. A total cohort of 600 children (200 children per district) were selected and followed using passive surveillance for breakthrough confirmed malaria episodes during the five-month peak transmission season. Malaria incidence rate per person-months and number of malaria episodes among children in the two arms were compared. Kaplan-Meier failure estimates were used to compare the probability of a positive malaria test. Other factors that may influence malaria transmission and infection among children in the two arms were also assessed using multivariable cox proportional hazards regression model.

RESULTS

The malaria incidence rate was 3.0 and 38.8 per 100 person-months in the intervention and control groups, respectively. In the intervention areas 90.0% (361/400) of children did not experience any malaria episodes during the study period, compared to 15% (29/200) in the control area. The incidence rate ratio was 0.078 (95% CI 0.063-0.096), which corresponds to a protective effectiveness of 92% (95% CI 90.0-94.0) among children in the intervention area.

CONCLUSION

SMC using SPAQ provided high protective effect against malaria during the peak transmission season in children aged 3-59 months in the Karamoja sub-region of Uganda.

Effectiveness of seasonal malaria chemoprevention in three regions of Togo: a population-based longitudinal study from 2013 to 2020

BACKGROUND

In 2012, the World Health Organization (WHO) recommended seasonal malaria chemoprevention (SMC) in areas of high seasonal transmission. Though implemented since 2013, the effectiveness of SMC in Togo was never evaluated.

METHODS

This study concerned routine data from 2013 to 2020 mass SMC campaigns for children under five in all health facilities of three Regions of Togo. Treatment coverage, reasons for non-treatment, and SMC-attributable adverse reactions were analysed per year and treatment round. Random effect logistic models estimated SMC effectiveness per health district, year, and treatment round.

RESULTS

The overall coverage was 98% (7,971,877 doses for 8,129,668 children). Contraindication was the main reason for non-administration. Over the study period, confirmed malaria cases decreased from 11,269 (1st round of 2016) to 1395 (4th round of 2020). Only 2,398 adverse reactions were reported (prevalence: 3/10,000), but no severe Lyell syndrome or Stevens-Johnson-type skin reaction. Compared to 2016, malaria prevalence decrease was estimated at 22.6% in 2017 (p < 0.001) and 75% in 2020 (p < 0.001). SMC effectiveness ranged from 76.6% (2nd round) to 96.2% (4th round) comparison with the 1st round.

CONCLUSIONS

SMC reduced significantly malaria cases among children under five. The results reassure all actors and call for effort intensification to reach the WHO goals for 2030.

Seasonal Malaria Chemoprevention Implementation: Effect on Malaria Incidence and Immunity in a Context of Expansion of P. falciparum Resistant Genotypes with Potential Reduction of the Effectiveness in Sub-Saharan Africa

Seasonal Malaria Chemoprevention (SMC), which combines amodiaquine (AQ) with sulfadoxine-pyrimethamine (SP), is an effective and promising strategy, recommended by WHO, for controlling malaria morbidity and mortality in areas of intense seasonal transmission. Despite the effectiveness of this strategy, a number of controversies regarding the impact of the development of malaria-specific immunity and challenges of the strategy in the context of increasing and expanding antimalarial drugs resistance but also the limited coverage of the SMC in children make the relevance of the SMC questionable, especially in view of the financial and logistical investments. Indeed, the number of malaria cases in the target group, children under 5 years old, has increased while the implementation of SMC is been extended in several African countries. This ambivalence of the SMC strategy, the increase in the prevalence of malaria cases suggests the need to evaluate the SMC and understand some of the factors that may hinder the success of this strategy in the implementation areas. The present review discusses the impact of the SMC on malaria morbidity, parasite resistance to antimalarial drugs, molecular and the immunity affecting the incidence of malaria in children. This approach will contribute to improving the malaria control strategy in highly seasonal transmission areas where the SMC is implemented.

Intermittent preventive treatment for malaria in infants

BACKGROUND

Intermittent preventive treatment could help prevent malaria in infants (IPTi) living in areas of moderate to high malaria transmission in sub-Saharan Africa. The World Health Organization (WHO) policy recommended IPTi in 2010, but its adoption in countries has been limited.

OBJECTIVES

To evaluate the effects of intermittent preventive treatment (IPT) with antimalarial drugs to prevent malaria in infants living in malaria-endemic areas.

SEARCH METHODS

We searched the following sources up to 3 December 2018: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library), MEDLINE (PubMed), Embase (OVID), LILACS (Bireme), and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) and the WHO International Clinical Trials Registry Platform (ICTRP) portal for ongoing trials up to 3 December 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared IPT to placebo or no intervention in infants (defined as young children aged between 1 to 12 months) in malaria-endemic areas.

DATA COLLECTION AND ANALYSIS

The primary outcome was clinical malaria (fever plus asexual parasitaemia). Two review authors independently assessed trials for inclusion, evaluated the risk of bias, and extracted data. We summarized dichotomous outcomes and count data using risk ratios (RR) and rate ratios respectively, and presented all measures with 95% confidence intervals (CIs). We extracted protective efficacy values and their 95% CIs; when an included trial did not report this data, we calculated these values from the RR or rate ratio with its 95% CI. Where appropriate, we combined data in meta-analyses and assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 12 trials that enrolled 19,098 infants; all were conducted in sub-Saharan Africa. Three trials were cluster-RCTs. IPTi with sulfadoxine-pyrimethamine (SP) was evaluated in 10 trials from 1999 to 2013 (n = 15,256). Trials evaluating ACTs included dihydroartemisinin-piperaquine (1 trial, 147 participants; year 2013), amodiaquine-artesunate (1 study, 684 participants; year 2008), and SP-artesunate (1 trial, 676 participants; year 2008). The earlier studies evaluated IPTi with SP, and were conducted in Tanzania (in 1999 and 2006), Mozambique (2004), Ghana (2004 to 2005), Gabon (2005), Kenya (2008), and Mali (2009). One trial evaluated IPTi with amodiaquine in Tanzania (2000). Later studies included three conducted in Kenya (2008), Tanzania (2008), and Uganda (2013), evaluating IPTi in multiple trial arms that included artemisinin-based combination therapy (ACT). Although the effect size varied over time and between drugs, overall IPTi impacts on the incidence of clinical malaria overall, with a 30% reduction (rate ratio 0.70, 0.62 to 0.80; 10 studies, 10,602 participants). The effect of SP appeared to attenuate over time, with trials conducted after 2009 showing little or no effect of the intervention. IPTi with SP probably resulted in fewer episodes of clinical malaria (rate ratio 0.78, 0.69 to 0.88; 8 trials, 8774 participants, moderate-certainty evidence), anaemia (rate ratio 0.82, 0.68 to 0.98; 6 trials, 7438 participants, moderate-certainty evidence), parasitaemia (rate ratio 0.66, 0.56 to 0.79; 1 trial, 1200 participants, moderate-certainty evidence), and fewer hospital admissions (rate ratio 0.85, 0.78 to 0.93; 7 trials, 7486 participants, moderate-certainty evidence). IPTi with SP probably made little or no difference to all-cause mortality (risk ratio 0.93, 0.74 to 1.15; 9 trials, 14,588 participants, moderate-certainty evidence). Since 2009, IPTi trials have evaluated ACTs and indicate impact on clinical malaria and parasitaemia. A small trial of DHAP in 2013 shows substantive effects on clinical malaria (RR 0.42, 0.33 to 0.54; 1 trial, 147 participants, moderate-certainty evidence) and parasitaemia (moderate-certainty evidence).

AUTHORS' CONCLUSIONS

In areas of sub-Saharan Africa, giving antimalarial drugs known to be effective against the malaria parasite at the time to infants as IPT probably reduces the risk of clinical malaria, anaemia, and hospital admission. Evidence from SP studies over a 19-year period shows declining efficacy, which may be due to increasing drug resistance. Combinations with ACTs appear promising as suitable alternatives for IPTi.

School-based screening and treatment may reduce P. falciparum transmission

In areas where malaria remains entrenched, novel transmission-reducing interventions are essential for malaria elimination. We report the impact screening-and-treatment of asymptomatic Malawian schoolchildren (n = 364 in the rainy season and 341 in the dry season) had on gametocyte-the parasite stage responsible for human-to-mosquito transmission-carriage. We used concomitant household-based surveys to predict the potential reduction in transmission in the surrounding community. Among 253 students with P. falciparum infections at screening, 179 (71%) had infections containing gametocytes detected by Pfs25 qRT-PCR. 84% of gametocyte-containing infections were detected by malaria rapid diagnostic test. While the gametocyte prevalence remained constant in untreated children, treatment with artemether-lumefantrine reduced the gametocyte prevalence (p < 0.0001) from 51.8 to 9.7% and geometric mean gametocyte density (p = 0.008) from 0.52 to 0.05 gametocytes/microliter. In community surveys, 46% of all gametocyte-containing infections were in school-age children, who comprised only 35% of the population. Based on these estimates six weeks after the intervention, the gametocyte burden in the community could be reduced by 25-55% depending on the season and the measure used to characterize gametocyte carriage. Thus, school-based interventions to treat asymptomatic infections may be a high-yield approach to not only improve the health of schoolchildren, but also decrease malaria transmission.

Antibodies Against the Plasmodium vivax Apical Membrane Antigen 1 From the Belem Strain Share Common Epitopes Among Other Worldwide Variants

Malaria is a human parasitic disease distributed in many tropical countries and caused by various Plasmodium species. Plasmodium vivax has the largest geographical distribution of the Plasmodium species and is predominant in the Americas, including Brazil. Only a small number of P. vivax vaccine formulations have successfully reached clinical trials relative to their P. falciparum counterparts. One of the candidate antigens for a blood-stage P. vivax vaccine is apical membrane antigen 1 (PvAMA-1). Due to the worldwide distribution of Plasmodium parasites, a high degree of variability has been detected in this antigen sequence, representing a considerable challenge to the development of a universal vaccine against malaria. In this study, we evaluated how PvAMA-1 polymorphisms influence vaccine-derived immune responses in P. vivax malaria. To this end, we expressed 9 recombinant protein representatives of different PvAMA-1 allelic variants in the yeast Pichia pastoris: Belem, Chesson I, Sal-1, Indonesia XIX, SK0814, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS. After protein expression and purification, we evaluated the breadth of the immune responses derived from malaria-exposed individuals from the Amazon region. From 611 serum samples of malaria-exposed individuals, 53.68% of them reacted against the PvAMA-1 Belem through ELISA. Positive samples were further tested against recombinant proteins representing the other PvAMA-1 allelic variants. Whereas Sal-1, Chesson I and SK0814 variants were highly recognized by tested serum samples, Indonesia XIX, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS were only slightly recognized. Moreover, polyclonal sera derived from C57BL/6 mice immunized with the PvAMA-1 Belem protein predominantly recognized Belem, Sal-1, Chesson I, SK0814, and Indonesia XIX through ELISA. Last, ELISA-based competition assays demonstrated that a previous interaction between anti-Belem polyclonal serum and Sal-1, Chesson I, SK0814, or Indonesia XIX proteins could further inhibit antibody binding to the Belem variant. Our human and mouse data suggest the presence of common epitopes or cross-reactivity between Belem, Sal-1, Chesson I, and SK0814 variants. Although the PvAMA-1 Belem variant induces strain-transcendent antibodies, PvAMA-1 variants from Thailand and Papua New Guinea may need to be included in a universal vaccine formulation to achieve protection against P. vivax malaria.

Evolution of Malaria Incidence in Five Health Districts, in the Context of the Scaling Up of Seasonal Malaria Chemoprevention, 2016 to 2018, in Mali

Context: In Mali, malaria transmission is seasonal, exposing children to high morbidity and mortality. A preventative strategy called Seasonal Malaria Chemoprevention (SMC) is being implemented, consisting of the distribution of drugs at monthly intervals for up to 4 months to children between 3 and 59 months of age during the period of the year when malaria is most prevalent. This study aimed to analyze the evolution of the incidence of malaria in the general population of the health districts of Kati, Kadiolo, Sikasso, Yorosso, and Tominian in the context of SMC implementation. Methods: This is a transversal study analyzing the routine malaria data and meteorological data of Nasa Giovanni from 2016 to 2018. General Additive Model (GAM) analysis was performed to investigate the relationship between malaria incidence and meteorological factors. Results: From 2016 to 2018, the evolution of the overall incidence in all the study districts was positively associated with the relative humidity, rainfall, and minimum temperature components. The average monthly incidence and the relative humidity varied according to the health district, and the average temperature and rainfall were similar. A decrease in incidence was observed in children under five years old in 2017 and 2018 compared to 2016. Conclusion: A decrease in the incidence of malaria was observed after the SMC rounds. SMC should be applied at optimal periods.

Effect of 4 years of seasonal malaria chemoprevention on the acquisition of antibodies to Plasmodium falciparum antigens in Ouelessebougou, Mali

Background

More than 200 million people live in areas of highly seasonal malaria transmission where Seasonal Malaria Chemoprevention (SMC) with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) was recommended in 2012 by WHO. This strategy is now implemented widely and protected more than 19 million children in 2018. It was previously reported that exposure to SMC reduced antibody levels to AMA1, MSP-1₄₂ and CSP, but the duration of exposure to SMC up to three 3 years, had no effect on antibody levels to MSP-1₄₂ and CSP.

Methods

In 2017, a cross-sectional survey was carried out 1 month after the last dose of SMC had been given to children aged 4–5 years randomly selected from areas where SMC had been given for 2 or 4 years during the malaria transmission season. A total of 461 children were enrolled, 242 children in areas where SMC had been implemented for 4 years and 219 children in areas where SMC had been implemented for 2 years. Antibody extracted from dry blood spots was used to measure IgG levels to the malaria antigens CSP, MSP-1₄₂ and AMA1 by ELISA.

Results

The prevalence of antibodies to MSP-1₄₂ was similar in children who had received SMC for 4 years compared to those who had received SMC for only 2 years (85.1 vs 86.0%, ajusted odd ratio (aOR) = 1.06, 95% confidence intervals (CI 0.62–1.80), p = 0.80). The prevalence of antibodies to AMA-1 and to CSP was not lower in children who received SMC for 4 years compared to those who had received SMC for only 2 years (95.3 vs 88.8%, aOR = 3.16, 95% CI 1.44–6.95, p = 0.004 for AMA-1; and 91.2 vs 81.9%, aOR = 3.14, 95% CI 1.70–5.76, p < 0.001 for CSP). Median antibody levels for anti-MSP-1₄₂ IgG were not significatively inferior in children who had received SMC for four rather than 2 years (0.88 (IQR: 0.64–1.15) and 0.95 ((0.68–1.15), respectively), anti-CSP (1.30 (1.00–1.56) and 1.17 (0.87–1.47)), and anti-AMA-1 (1.45 (1.24–1.68) and 1.41 (1.17–1.64)).

Conclusion

In an area of high seasonal malaria transmission, children who had received SMC for 4 years did not had lower seropositivity or antibody levels to AMA1, MSP-1₄₂ and CSP compared to children who had received SMC for only 2 years suggesting that children who have received SMC for 4 years may not be more at risk of malaria after the cessation of SMC than children who have received SMC for a shorter period.

Impact of Three-Year Intermittent Preventive Treatment Using Artemisinin-Based Combination Therapies on Malaria Morbidity in Malian Schoolchildren

Previous studies have shown that a single season of intermittent preventive treatment in schoolchildren (IPTsc) targeting the transmission season has reduced the rates of clinical malaria, all-cause clinic visits, asymptomatic parasitemia, and anemia. Efficacy over the course of multiple years of IPTsc has been scantly investigated. Methods: An open, randomized-controlled trial among schoolchildren aged 6–13 years was conducted from September 2007 to January 2010 in Kolle, Mali. Students were included in three arms: sulphadoxine-pyrimethamine+artesunate (SP+AS), amodiaquine+artesunate (AQ+AS), and control (C). All students received two full doses, given 2 months apart, and were compared with respect to the incidence of clinical malaria, all-cause clinic visits, asymptomatic parasitemia, and anemia. Results: A total of 296 students were randomized. All-cause clinic visits were in the SP+AS versus control (29 (20.1%) vs. 68 (47.2%); 20 (21.7%) vs. 41 (44.6%); and 14 (21.2%) vs. 30 (44.6%); p < 0.02) in 2007, 2008, and 2009, respectively. The prevalence of asymptomatic parasitemia was lower in the SP+AS compared to control (38 (7.5%) vs. 143 (28.7%); and 47 (12.7%) vs. 75 (21.2%); p < 0.002) in 2007 and 2008, respectively. Hemoglobin concentration was significantly higher in children receiving SP+AS (11.96, 12.06, and 12.62 g/dL) than in control children (11.60, 11.64, and 12.15 g/dL; p < 0.001) in 2007, 2008, and 2009, respectively. No impact on clinical malaria was observed. Conclusion: IPTsc with SP+AS reduced the rates of all-cause clinic visits and anemia during a three-year implementation.

Two-Year Scale-Up of Seasonal Malaria Chemoprevention Reduced Malaria Morbidity among Children in the Health District of Koutiala, Mali

BACKGROUND

Previous controlled studies demonstrated seasonal malaria chemoprevention (SMC) reduces malaria morbidity by >80% in children aged 3-59 months. Here, we assessed malaria morbidity after large-scale SMC implementation during a pilot campaign in the health district of Koutiala, Mali.

METHODS

Starting in August 2012, children received three rounds of SMC with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ). From July 2013 onward, children received four rounds of SMC. Prevalence of malaria infection, clinical malaria and anemia were assessed during two cross-sectional surveys conducted in August 2012 and June 2014. Investigations involved 20 randomly selected clusters in 2012 against 10 clusters in 2014.

RESULTS

Overall, 662 children were included in 2012, and 670 in 2014. Children in 2014 versus those surveyed in 2012 showed reduced proportions of malaria infection (12.4% in 2014 versus 28.7% in 2012 (p = 0.001)), clinical malaria (0.3% versus 4.2%, respectively (p < 0.001)), and anemia (50.1% versus 67.4%, respectively (p = 0.001)). A propensity score approach that accounts for environmental differences showed that SMC conveyed a significant protective effect against malaria infection (IR = 0.01, 95% CI (0.0001; 0.09), clinical malaria (OR = 0.25, 95% CI (0.06; 0.85)), and hemoglobin concentration (β = 1.3, 95% CI (0.69; 1.96)) in 2012 and 2014, respectively.

CONCLUSION

SMC significantly reduced frequency of malaria infection, clinical malaria and anemia two years after SMC scale-up in Koutiala.

Impact of seasonal malaria chemoprevention in children aged 3 to 59 months in the Kangaba and Kolokani health districts between 2013 and 2015

INTRODUCTION

Malaria is a public health problem in Mali. Seasonal chemo prevention (SCP) is of particular importance, hence its introduction by the WHO since 2012 in children aged 3 to 59 months from the start of the transmission season. This study aims to demonstrate the impact of SCP on malaria in the health districts of Kangaba and Kolokani.

MATERIALS AND METHODS

Our retrospective study was carried out from 2013 to 2015 in the health districts of Kangaba and Kolokani using the databases of the NGO AMCP / ALIMA. Data from 2014 and 2015 were compared to data from 2013.

RESULTS

The number of malaria cases in children under 5year in the area covered by the SCP shows a considerable decrease in Kangaba of 52% in 2014 and 49% in 2015, compared to the reference period being the year 2013. In Kolokani the decrease is 57% in 2014 and 40% in 2015 compared to the year 2013. Compared to deaths, a decrease of 50.5% was recorded in 2014 and 60.4% in 2015 compared to the year 2013, i.e. 51 and 61 fewer deaths compared to 2013, respectively, in health facilities.

CONCLUSION

The SCP had made it possible to reduce significant mortality and malaria morbidity in the two health districts of Kangaba and Kolokani.

Understanding the Pyrimethamine Drug Resistance Mechanism via Combined Molecular Dynamics and Dynamic Residue Network Analysis

In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand the contribution of four point mutations (N51I, C59R, S108N, and I164L) within the active site of the malaria parasite enzyme dihydrofolate reductase (DHFR) towards the resistance of the antimalarial drug pyrimethamine. Homology modeling was used to obtain full-length models of wild type (WT) and mutant DHFR. Molecular docking was employed to dock pyrimethamine onto the generated structures. Subsequent all-atom molecular dynamics (MD) simulations and binding free-energy computations highlighted that pyrimethamine's stability and affinity inversely relates to the number of mutations within its binding site and, hence, resistance severity. Generally, mutations led to reduced binding affinity to pyrimethamine and increased conformational plasticity of DHFR. Next, dynamic residue network analysis (DRN) was applied to determine the impact of mutations and pyrimethamine binding on communication dispositions of DHFR residues. DRN revealed residues with distinctive communication profiles, distinguishing WT from drug-resistant mutants as well as pyrimethamine-bound from pyrimethamine-free models. Our results provide a new perspective on the understanding of mutation-induced drug resistance.

Intermittent preventive treatment for malaria in infants

BACKGROUND

Intermittent preventive treatment could help prevent malaria in infants (IPTi) living in areas of moderate to high malaria transmission in sub-Saharan Africa. The World Health Organization (WHO) policy recommended IPTi in 2010, but its adoption in countries has been limited.

OBJECTIVES

To evaluate the effects of intermittent preventive treatment (IPT) with antimalarial drugs to prevent malaria in infants living in malaria-endemic areas.

SEARCH METHODS

We searched the following sources up to 3 December 2018: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library), MEDLINE (PubMed), Embase (OVID), LILACS (Bireme), and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) and the WHO International Clinical Trials Registry Platform (ICTRP) portal for ongoing trials up to 3 December 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared IPT to placebo or no intervention in infants (defined as young children aged between 1 to 12 months) in malaria-endemic areas.

DATA COLLECTION AND ANALYSIS

The primary outcome was clinical malaria (fever plus asexual parasitaemia). Two review authors independently assessed trials for inclusion, evaluated the risk of bias, and extracted data. We summarized dichotomous outcomes and count data using risk ratios (RR) and rate ratios respectively, and presented all measures with 95% confidence intervals (CIs). We extracted protective efficacy values and their 95% CIs; when an included trial did not report this data, we calculated these values from the RR or rate ratio with its 95% CI. Where appropriate, we combined data in meta-analyses and assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 12 trials that enrolled 19,098 infants; all were conducted in sub-Saharan Africa. Three trials were cluster-RCTs. IPTi with sulfadoxine-pyrimethamine (SP) was evaluated in 10 trials from 1999 to 2013 (n = 15,256). Trials evaluating ACTs included dihydroartemisinin-piperaquine (1 trial, 147 participants; year 2013), amodiaquine-artesunate (1 study, 684 participants; year 2008), and SP-artesunate (1 trial, 676 participants; year 2008). The earlier studies evaluated IPTi with SP, and were conducted in Tanzania (in 1999 and 2006), Mozambique (2004), Ghana (2004 to 2005), Gabon (2005), Kenya (2008), and Mali (2009). One trial evaluated IPTi with amodiaquine in Tanzania (2000). Later studies included three conducted in Kenya (2008), Tanzania (2008), and Uganda (2013), evaluating IPTi in multiple trial arms that included artemisinin-based combination therapy (ACT). Although the effect size varied over time and between drugs, overall IPTi impacts on the incidence of clinical malaria overall, with a 27% reduction (rate ratio 0.73, 0.65 to 0.82; 10 studies, 10,602 participants). The effect of SP appeared to attenuate over time, with trials conducted after 2009 showing little or no effect of the intervention. IPTi with SP probably resulted in fewer episodes of clinical malaria (rate ratio 0.79, 0.74 to 0.85; 8 trials, 8774 participants, moderate-certainty evidence), anaemia (rate ratio 0.82, 0.68 to 0.98; 6 trials, 7438 participants, moderate-certainty evidence), parasitaemia (rate ratio 0.66, 0.56 to 0.79; 1 trial, 1200 participants, moderate-certainty evidence), and fewer hospital admissions (rate ratio 0.85, 0.78 to 0.93; 7 trials, 7486 participants, moderate-certainty evidence). IPTi with SP probably made little or no difference to all-cause mortality (risk ratio 0.93, 0.74 to 1.15; 9 trials, 14,588 participants, moderate-certainty evidence). Since 2009, IPTi trials have evaluated ACTs and indicate impact on clinical malaria and parasitaemia. A small trial of DHAP in 2013 shows substantive effects on clinical malaria (RR 0.42, 0.33 to 0.54; 1 trial, 147 participants, moderate-certainty evidence) and parasitaemia (moderate-certainty evidence).

AUTHORS' CONCLUSIONS

In areas of sub-Saharan Africa, giving antimalarial drugs known to be effective against the malaria parasite at the time to infants as IPT probably reduces the risk of clinical malaria, anaemia, and hospital admission. Evidence from SP studies over a 19-year period shows declining efficacy, which may be due to increasing drug resistance. Combinations with ACTs appear promising as suitable alternatives for IPTi. 2 December 2019 Up to date All studies incorporated from most recent search All eligible published studies found in the last search (3 Dec, 2018) were included.

Comparative effectiveness of malaria prevention measures: a systematic review and network meta-analysis

Background

Malaria causes significant morbidity and mortality worldwide. There are several preventive measures that are currently employed, including insecticide-treated nets (ITNs, including long-lasting insecticidal nets and insecticidal-treated bed nets), indoor residual spraying (IRS), prophylactic drugs (PD), and untreated nets (UN). However, it is unclear which measure is the most effective for malaria prevention. We therefore undertook a network meta-analysis to compare the efficacy of different preventive measures on incidence of malaria infection.

Methods

A systematic literature review was undertaken across four medical and life sciences databases (PubMed, Cochrane Central, Embase, and Web of Science) from their inception to July 2016 to compare the effectiveness of different preventive measures on malaria incidence. Data from the included studies were analysed for the effectiveness of several measures against no intervention (NI). This was carried out using an automated generalized pairwise modeling (GPM) framework for network meta-analysis to generate mixed treatment effects against a common comparator of no intervention (NI).

Results

There were 30 studies that met the inclusion criteria from 1998–2016. The GPM framework led to a final ranking of effectiveness of measures in the following order from best to worst: PD, ITN, IRS and UN, in comparison with NI. However, only ITN (RR: 0.49, 95% CI: 0.32–0.74) showed precision while other methods [PD (RR: 0.24, 95% CI: 0.004–15.43), IRS (RR: 0.55, 95% CI: 0.20–1.56) and UN (RR: 0.73, 95% CI: 0.28–1.90)] demonstrating considerable uncertainty associated with their point estimates.

Conclusion

Current evidence is strong for the protective effect of ITN interventions in malaria prevention. Even though ITNs were found to be the only preventive measure with statistical support for their effectiveness, the role of other malaria control measures may be important adjuncts in the global drive to eliminate malaria.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2783-y) contains supplementary material, which is available to authorized users.

Seasonal malaria chemoprevention: successes and missed opportunities

Seasonal malaria chemoprevention (SMC) was recommended in 2012 for young children in the Sahel during the peak malaria transmission season. Children are given a single dose of sulfadoxine/pyrimethamine combined with a 3-day course of amodiaquine, once a month for up to 4 months. Roll-out and scale-up of SMC has been impressive, with 12 million children receiving the intervention in 2016. There is evidence of its overall benefit in routine implementation settings, and a meta-analysis of clinical trial data showed a 75% decrease in clinical malaria compared to placebo. SMC is not free of shortcomings. Its target zone includes many hard-to-reach areas, both because of poor infrastructure and because of political instability. Treatment adherence to a 3-day course of preventive treatment has not been fully documented, and could prove challenging. As SMC is scaled up, integration into a broader, community-based paradigm which includes other preventive and curative activities may prove beneficial, both for health systems and for recipients.

Effect of seasonal malaria chemoprevention on the acquisition of antibodies to Plasmodium falciparum antigens in Ouelessebougou, Mali

BACKGROUND

Seasonal malaria chemoprevention (SMC) is a new strategy to reduce malaria burden in young children in Sahelian countries. It consists of the administration of full treatment courses of sulfadoxine-pyrimethamine plus amodiaquine to children at monthly intervals during the malaria season. However, it is not clear if there is a cumulative effect of SMC over time on acquisition of antibodies to malaria antigens.

METHODS

A cross-sectional serosurvey was carried out 1 month after the last dose of SMC in 2016. Children aged 3-4 years were randomly selected from areas where SMC was given for 1, 2 or 3 years during the malaria season. Children in the areas where SMC had been implemented for 1 year but who failed to receive SMC were used as comparison group. Antibody extracted from dry blood spots was used to measure IgG levels to CSP, MSP-1₄₂ and AMA1.

RESULTS

The prevalence of antibodies to AMA-1 were high and similar in children who received SMC for 1, 2 or 3 years and also when compared to those who never received SMC (96.3 vs 97.5%, adjusted OR = 0.99, 95% CI 0.33-2.97, p = 0.99). The prevalence of antibodies to MSP-1₄₂ and to CSP were similar in children that received SMC for 1, 2 or 3 years, but were lower in these children compared to those who did not receive SMC (87.1 vs 91.2%, adjusted OR = 0.55, 95% CI 0.29-1.01, p = 0.05 for MSP-1₄₂; 79.8 vs 89.2%, adjusted OR = 0.52, 95% CI 0.30-0.90, p = 0.019 for CSP).

CONCLUSIONS

SMC reduced seropositivity to MSP-1₄₂ and CSP, but the duration of SMC did not further reduce seropositivity. Exposure to SMC did not reduce the seropositivity to AMA1.

The end of a dogma: the safety of doxycycline use in young children for malaria treatment

Anti-malarial drug resistance to chloroquine and sulfadoxine–pyrimethamine has spread from Southeast Asia to Africa. Furthermore, the recent emergence of resistance to artemisinin-based combination therapy (ACT) in Southeast Asia highlights the need to identify new anti-malarial drugs. Doxycycline is recommended for malaria chemoprophylaxis for travel in endemic areas, or in combination with the use of quinine for malaria treatment when ACT is unavailable or when the treatment of severe malaria with artesunate fails. However, doxycycline is not used in young children under 8 years of age due to its contraindication due to the risk of yellow tooth discolouration and dental enamel hypoplasia. Doxycycline was developed after tetracycline and was labelled with the same side-effects as the earlier tetracyclines. However, recent studies report little or no effects of doxycycline on tooth staining or dental enamel hypoplasia in children under 8 years of age. In the United States, the Centers for Disease Control and Prevention have recommended the use of doxycycline for the treatment of acute and chronic Q fever and tick-borne rickettsial diseases in young children. It is time to rehabilitate doxycycline and to recommend it for malaria treatment in children under 8 years of age.

A prospective comparative field study to evaluate the efficacy of a traditional plant-based malaria prophylaxis

Background:

An unceasing threat of resistance of malarial parasites to available antimalarial drugs makes the development of new drugs imperative. Natural plant-based products are an alternative source for discovering new antimalarial drugs.

Aim:

To determine the prophylactic efficacy of a traditionally used plant-based drug on prevention of malaria in endemic villages of Odisha, India.

Methods:

A total of 267 healthy human volunteers of both sexes, aged 18-60 years were enrolled in Odisha, India, to receive either minimum 20 doses of aqueous extract of Traditional Plant-based Malaria Prophylactic drug 74, twice a week (experimental group), or no drug (control group) for 14 weeks. The primary criterion was the occurrence of malaria positive cases confirmed through expert microscopy during the study period. Analyses were by per-protocol (PP) and modified intention-to-treat (mITT).

Results:

A significant (P < 0.01) reduction (64%) of malaria incidence was observed in the experimental group compared to control group, 12.3% and 26.6%, respectively, as PP analysis. However, the reduction was nonsignificant as per mITT analysis (P = 0.22). The experimental group showed a relative risk of 0.36 compared to control group.

Conclusion:

This preliminary study constitutes a potential “proof of concept” for the development of malaria prophylactic drug and provide a scientific basis for the use of traditional remedy as a malaria preventive by tribal populations in India.

Efficacy and safety of intermittent preventive treatment in schoolchildren with sulfadoxine/pyrimethamine (SP) and SP plus piperaquine in Democratic Republic of the Congo: a randomised controlled trial

In endemic areas, malaria and its adverse effects in schoolchildren may be prevented by intermittent preventive treatment (IPTsc). However, the most appropriate drug regimen for IPTsc remains to be identified. A randomised controlled trial was conducted in Kinshasa, DRC. Enrolled schoolchildren were assigned to a passive control arm (n = 212), sulfadoxine/pyrimethamine (SP) (n = 202) or SP plus piperaquine (SP/PQ) (n = 202). The primary endpoint was haemoglobin (Hb) change. Secondary endpoints were anaemia, parasitaemia prevalence and clinical malaria incidence. Data were analysed by modified intention-to-treat (mITT) and per-protocol. A linear mixed mode was used due to repeated measurements. Of 616 enrolled children, 410 (66.6%) were eligible for mITT analysis. The control arm was used as reference. After 12 months, the Hb level increased by 0.20 g/dL (95% CI -0.61 to 0.47; P = 0.168) and 0.39 g/dL (0.12-0.66; P <0.01) in the SP and SP/PQ arms, respectively. SP treatment reduced anaemia, malaria parasitaemia and clinical malaria by 10% (0-20%; P = 0.06), 19% (2-33%; P = 0.042) and 25% (-32 to 57%; P = 0.37), respectively. The corresponding values for SP/PQ were 28% (19-37%; P <0.001), 40% (26-52%; P <0.001) and 58% (17-79%; P <0.01). No deaths or severe adverse events (SAEs) were observed. SP/PQ offered substantial protection against anaemia, malaria parasitaemia and clinical malaria and showed no SAEs. SP/PQ, a combination of two long-acting non-artemisinin-based antimalarials, may be a valuable option for IPTsc in Africa.

Impact of combined intermittent preventive treatment of malaria and helminths on anaemia, sustained attention, and recall in Northern Ghanaian schoolchildren

BACKGROUND

The benefits of integrated control of malaria, schistosomiasis, and soil-transmitted helminth infections have not been fully explored in Ghanaian schoolchildren.

OBJECTIVE

To assess the impact of co-administered artemether-lumefantrine plus albendazole, and artemether-lumefantrine plus albendazole plus praziquantel compared to albendazole plus praziquantel on anaemia, sustained attention, and recall in schoolchildren.

DESIGN

This three-arm, open-label intervention study was carried out in Ghana among class three schoolchildren. Artemether-lumefantrine and albendazole were co-administered to 131 schoolchildren in Study Arm 1; artemether-lumefantrine, albendazole, and praziquantel to 90 children in Study Arm 2 versus albendazole and praziquantel to 127 children in Control Arm 3. Medicines were administered to all children at least 30 min after a meal. A HemoCue(®) photometer was used to measure haemoglobin (Hb), while the code transmission test (CTT), adapted from the Test of Everyday Attention for Children (TEA-Ch), was used to measure sustained attention and recall before-and-after interventions in June 2011 and June 2012.

RESULTS

We observed significant malaria parasite prevalence reductions of 62.8 and 59.2% in Study Arm 1 from 24.2 to 9.0%, p<0.01, and 59.2% in Study Arm 2 from 26.7 to 10.9%, p<0.01), respectively, compared to 8.93% in Control Arm 3 (from 34.7 to 31.6%, p>0.05). Meanwhile, anaemia prevalence reduced significantly (p<0.01) in all three study arms after interventions by 38.4% (from 19.8 to 12.2%), 20.7% (from 26.6 to 21.1%), and 36.0% (from 28.3 to 18.1%) in Study Arms 1, 2, and 3, respectively. Although the interventions had no significant effects on Hb levels, anaemia prevalence reduced insignificantly by 38.4 and 20.7% in Study Arms 1 and 2, respectively, compared to 36.0% in Control Arm 3. Among schoolchildren in Study Arms 1 and 2, mean CTT score improved significantly after interventions by 10.4% (from 3.18 to 3.55, p=0.01) and 20.5% (from 2.83 to 3.56, p=0.01) respectively, compared to 5.75% in Control Arm 3 (from 2.95 to 3.13, p=0.09). Likewise, mean recall test score improvements after interventions were 16.9% (from 2.07 to 2.49, p=0.01) and 27.9% (from 1.91 to 2.65, p=0.01) in Study Arms 1 and 2, respectively, compared to 18.3% (from 1.92 to 2.35, p=0.01) in Control Arm 3.

CONCLUSION

Combined intermittent preventive treatment of malaria and deworming reduced prevalence of anaemia and improved sustained attention and recall in schoolchildren. Best results for sustained attention and recall were seen in Study Arm 2.

In Vivo Efficacy and Parasite Clearance of Artesunate + Sulfadoxine-Pyrimethamine Versus Artemether-Lumefantrine in Mali

Although artemisinin resistance has yet to be reported in Africa, surveillance of the efficacy of artemisinin-based combination therapies (ACTs) is warranted. Here, the efficacy of artesunate + sulfadoxine-pyrimethamine (AS + SP) and artemether-lumefantrine (AL) was evaluated in Mali. Randomized open-label comparative in vivo assay of AS + SP versus AL were carried out using the 28-day follow-up World Health Organization protocol. Patients with uncomplicated falciparum malaria and at least 6 months of age were recruited between October 2010 and January 2014. A subset of these patients was selected to measure Plasmodium falciparum clearance time. Polymerase chain reaction-corrected adequate clinical and parasitological responses were 100% for AS + SP and 98.2% for AL with no significant difference (P = 0.06). The reinfection rates were comparable (P = 0.63) with 8.0% for AS + SP and 12.6% for AL. Individuals under 8 years were more susceptible to treatment failure (relative risk = 1.9; 95% confidence interval = 1.2, 3.3). Median parasite clearance half-life was 1.7 hours (interquartile range [IQR] = 1.3-2.2) for AS + SP and 1.9 hours (IQR = 1.5-2.5) for AL with no statistically significant difference (P = 0.24). Efficacy of AS + SP and AL was high. This study provides baseline information on parasite clearance half-lives after ACT treatment, particularly AS + SP, in Mali.

Efficacy and safety of intermittent preventive treatment for malaria in schoolchildren: a systematic review

Background

Intermittent preventive treatment (IPT) is a proven malaria control strategy in infants and pregnancy. School-aged children represent 26 % of the African population, and an increasing percentage of them are scholarized. Malaria is causing 50 % of deaths in this age group and malaria control efforts may shift the malaria burden to older age groups. Schools have been suggested as a platform for health interventions delivery (deworming, iron-folic acid, nutrients supplementation, (boost-)immunization) and as a possible delivery system for IPT in schoolchildren (IPTsc). However, the current evidence on the efficacy and safety of IPTsc is limited and the optimal therapeutic regimen remains controversial.

Methods

A systematic search for studies reporting efficacy and safety of IPT in schoolchildren was conducted using PubMed, Web of Science, Clinicaltrials and WHO/ICTRP database, and abstracts from congresses with the following key words: intermittent, preventive treatment AND malaria OR Plasmodium falciparum AND schoolchildren NOT infant NOT pregnancy.

Results

Five studies were identified. Most IPTsc regimes demonstrated substantial protection against malaria parasitaemia, with dihydroartemisinin-piperaquine (DP) given monthly having the highest protective effect (PE) (94 %; 95 % CI 93–96). Contrarily, SP did not provide any PE against parasitaemia. However, no IPT regimen provided a PE above 50 % in regard to anaemia, and highest protection was provided by SP+ amodiaquine (AQ) given four-monthly (50 %; 95 % CI 41–53). The best protection against clinical malaria was observed in children monthly treated with DP (97 %; 95 % CI 87–98). However, there was no protection when the drug was given three-monthly. No severe adverse events were associated with the drugs used for IPTsc.

Conclusion

IPTsc may reduce the malaria-related burden in schoolchildren. However, more studies assessing efficacy of IPT in particular against malaria-related anaemia and clinical malaria in schoolchildren must be conducted.

The role of community participation in intermittent preventive treatment of childhood malaria in southeastern Ghana

BACKGROUND

Malaria remains a major cause of morbidity and mortality in Ghana. Very little attention was paid to community participation in malaria control in the past and this has affected most of the desired outcomes. The recent recognition of the importance of community participation in malaria control had informed the implementation of Intermittent Preventive Treatment of Childhood Malaria (IPTc). The intervention was implemented in the Shime sub-district of the Keta District in Ghana and this paper reports the evaluation of the community involvement aspect of the project.

METHOD

Semi-structured questionnaire were administered to 105 randomly selected caregivers. A focus group discussion was organized for nine Community Assistants (CAs) and 16 in-depth interviews were conducted with opinion leaders. The tools were used to investigate community attitudes towards, level of awareness and acceptance of the intervention. The benefits of the project and the preferred mode of drug delivery were also investigated.

RESULTS

Findings indicated that, the people were aware of the project in their communities. They showed high level of participation and have accepted the intervention as their own. There was a reported reduction in hospital attendance from 52.4% to 6.7%, which led to perceived savings for caregivers. The people preferred that community members deliver the drugs because they are more approachable, caring and sensitive to their health needs than the nurses.

CONCLUSION

The approach adopted by entrusting the intervention into the hands of the community members by allowing them to select their own CAs coupled with the observation of necessary community protocols had led to high level of participation, acceptance and successful outcome of the intervention.

The High Burden of Malaria in Primary School Children in Southern Malawi

Malaria among school children has received increased attention recently, yet there remain few detailed data on the health and educational burden of malaria, especially in southern Africa. This paper reports a survey among school children in 50 schools in Zomba District, Malawi. Children were assessed for Plasmodium infection, anemia, and nutritional status and took a battery of age-appropriate tests of attention, literacy, and numeracy. Overall, 60.0% of children were infected with Plasmodium falciparum, 32.4% were anemic and 32.4% reported sleeping under a mosquito net the previous night. Patterns of P. falciparum infection and anemia varied markedly by school. In multivariable analysis, higher odds of P. falciparum infection were associated with younger age and being stunted, whereas lower odds were associated with reported net use, higher parental education, and socioeconomic status. The odds of anemia were significantly associated with P. falciparum infection, with a dose-response relationship between density of infection and odds of anemia. No clear relationship was observed between health status and cognitive and educational outcomes. The high burden of malaria highlights the need to tackle malaria among school children.

Malaria in school-age children in Africa: an increasingly important challenge

School-age children have attracted relatively little attention as a group in need of special measures to protect them against malaria. However, increasing success in lowering the level of malaria transmission in many previously highly endemic areas will result in children acquiring immunity to malaria later in life than has been the case in the past. Thus, it can be anticipated that in the coming years there will be an increase in the incidence of both uncomplicated and severe malaria in school-age children in many previously highly endemic areas. In this review, which focuses primarily on Africa, recent data on the prevalence of malaria parasitaemia and on the incidence of clinical malaria in African school-age children are presented and evidence that malaria adversely effects school performance is reviewed. Long-lasting insecticide treated bednets (LLIN) are an effective method of malaria control but several studies have shown that school-age children use LLINs less frequently than other population groups. Antimalarial drugs are being used in different ways to control malaria in school-age children including screening and treatment and intermittent preventive treatment. Some studies of chemoprevention in school-age children have shown reductions in anaemia and improved school performance but this has not been the case in all trials and more research is needed to identify the situations in which chemoprevention is likely to be most effective and, in these situations, which type of intervention should be used. In the longer term, malaria vaccines may have an important role in protecting this important section of the community from malaria. Regardless of the control approach selected, it is important this is incorporated into the overall programme of measures being undertaken to enhance the health of African school-age children.

Impact of intermittent preventive treatment with dihydroartemisinin-piperaquine on malaria in Ugandan schoolchildren: a randomized, placebo-controlled trial

Dihydroartemisinin-piperaquine administered at monthly intervals, but not that dosed once a school term, is a remarkably effective measure for the prevention of incidence of malaria, prevalence of parasitemia, and prevalence of anemia in schoolchildren living in a high-transmission setting.

Background. Intermittent preventive treatment (IPT) in schoolchildren offers a promising option for malaria control. However, the optimal drug and dosing regimens for IPT remain to be determined.

Methods. We conducted a randomized, double-blind, placebo-controlled trial in 740 schoolchildren aged 6–14 years living in a setting of high malaria transmission in Uganda. Enrolled children were randomized to dihydroartemisinin-piperaquine (DP) given once a month (IPTm), DP given once a school term (4 treatments over 12 months, IPTst), or placebo and followed for 12 months. The primary outcome was the incidence of malaria over 12 months. Secondary outcomes included parasite prevalence and anemia over 12 months. Analyses were conducted on an intention-to-treat basis.

Results. In the placebo arm, the incidence of malaria was 0.34 episodes per person-year and the prevalence of parasitemia and anemia was 38% and 20%, respectively. IPTm reduced the incidence of malaria by 96% (95% confidence interval [CI], 88%–99%, P < .0001), the prevalence of asymptomatic parasitemia by 94% (95% CI, 92%–96%, P < .0001), and the prevalence of anemia by 40% (95% CI, 19%–56%, P < .0001). IPTst had no significant effect on the incidence of symptomatic malaria or the prevalence of anemia, but reduced the prevalence of asymptomatic parasitemia by 54% (95% CI, 47%–60%, P < .0001).

Conclusions. Monthly IPT with DP offered remarkable protection against clinical malaria, parasitemia, and anemia in schoolchildren living in a high-malaria-transmission setting.

Clinical Trials Registration.  NCT01231880.

Mass drug administration for malaria

BACKGROUND

Mass drug administration (MDA), defined as the empiric administration of a therapeutic antimalarial regimen to an entire population at the same time, has been a historic component of many malaria control and elimination programmes, but is not currently recommended. With renewed interest in MDA and its role in malaria elimination, this review aims to summarize the findings from existing research studies and program experiences of MDA strategies for reducing malaria burden and transmission.

OBJECTIVES

To assess the impact of antimalarial MDA on population asexual parasitaemia prevalence, parasitaemia incidence, gametocytaemia prevalence, anaemia prevalence, mortality and MDA-associated adverse events.

SEARCH METHODS

We searched the Cochrane Infectious Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE+, EMBASE, to February 2013. We also searched CABS Abstracts, LILACS, reference lists, and recent conference proceedings.

SELECTION CRITERIA

Cluster-randomized trials and non-randomized controlled studies comparing therapeutic MDA versus placebo or no MDA, and uncontrolled before-and-after studies comparing post-MDA to baseline data were selected. Studies administering intermittent preventive treatment (IPT) to sub-populations (for example, pregnant women, children or infants) were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed studies for inclusion, extracted data and assessed risk of bias. Studies were stratified by study design and then subgrouped by endemicity, by co-administration of 8-aminoquinoline plus schizonticide drugs and by plasmodium species. The quality of evidence was assessed using the GRADE approach.

MAIN RESULTS

Two cluster-randomized trials, eight non-randomized controlled studies and 22 uncontrolled before-and-after studies are included in this review. Twenty-two studies (29 comparisons) compared MDA to placebo or no intervention of which two comparisons were conducted in areas of low endemicity (≤5%), 12 in areas of moderate endemicity (6-39%) and 15 in areas of high endemicity (≥ 40%). Ten studies evaluated MDA plus other vector control measures. The studies used a wide variety of MDA regimens incorporating different drugs, dosages, timings and numbers of MDA rounds. Many of the studies are now more than 30 years old. Areas of low endemicity (≤5%)Within the first month post-MDA, a single uncontrolled before-and-after study conducted in 1955 on a small Taiwanese island reported a much lower prevalence of parasitaemia following a single course of chloroquine compared to baseline (1 study, very low quality evidence). This lower parasite prevalence was still present after more than 12 months (one study, very low quality evidence). In addition, one cluster-randomized trial evaluating MDA in a low endemic setting reported zero episodes of parasitaemia at baseline, and throughout five months of follow-up in both the control and intervention arms (one study, very low quality evidence). Areas of moderate endemicity (6-39%)Within the first month post-MDA, the prevalence of parasitaemia was much lower in three non-randomized controlled studies from Kenya and India in the 1950s (RR 0.03, 95% CI 0.01 to 0.08, three studies, moderate quality evidence), and in three uncontrolled before-and-after studies conducted between 1954 and 1961 (RR 0.29, 95% CI 0.17 to 0.48, three studies,low quality evidence).The longest follow-up in these settings was four to six months. At this time point, the prevalence of parasitaemia remained substantially lower than controls in the two non-randomized controlled studies (RR 0.18, 95% CI 0.10 to 0.33, two studies, low quality evidence). In contrast, the two uncontrolled before-and-after studies found mixed results: one found no difference and one found a substantially higher prevalence compared to baseline (not pooled, two studies, very low quality evidence). Areas of high endemicity (≥40%)Within the first month post-MDA, the single cluster-randomized trial from the Gambia in 1999 found no significant difference in parasite prevalence (one study, low quality evidence). However, prevalence was much lower during the MDA programmes in three non-randomized controlled studies conducted in the 1960s and 1970s (RR 0.17, 95% CI 0.11 to 0.27, three studies, moderate quality evidence), and within one month of MDA in four uncontrolled before-and-after studies (RR 0.37, 95% CI 0.28 to 0.49, four studies,low quality evidence).Four trials reported changes in prevalence beyond three months. In the Gambia, the single cluster-randomized trial found no difference at five months (one trial, moderate quality evidence). The three uncontrolled before-and-after studies had mixed findings with large studies from Palestine and Cambodia showing sustained reductions at four months and 12 months, respectively, and a small study from Malaysia showing no difference after four to six months of follow-up (three studies,low quality evidence). 8-aminoquinolines We found no studies directly comparing MDA regimens that included 8-aminoquinolines with regimens that did not. In a crude subgroup analysis with a limited number of studies, we were unable to detect any evidence of additional benefit of primaquine in moderate- and high-transmission settings. Plasmodium species In studies that reported species-specific outcomes, the same interventions resulted in a larger impact on Plasmodium falciparum compared to P. vivax.

AUTHORS' CONCLUSIONS

MDA appears to reduce substantially the initial risk of malaria parasitaemia. However, few studies showed sustained impact beyond six months post-MDA, and those that did were conducted on small islands or in highland settings.To assess whether there is an impact of MDA on malaria transmission in the longer term requires more quasi experimental studies with the intention of elimination, especially in low- and moderate-transmission settings. These studies need to address any long-term outcomes, any potential barriers for community uptake, and contribution to the development of drug resistance.

Epidemiology of malaria in an area of seasonal transmission in Niger and implications for the design of a seasonal malaria chemoprevention strategy

Background

Few data are available about malaria epidemiological situation in Niger. However, implementation of new strategies such as vaccination or seasonal treatment of a target population requires the knowledge of baseline epidemiological features of malaria. A population-based study was conducted to provide better characterization of malaria seasonal variations and population groups the most at risk in this particular area.

Methods

From July 2007 to December 2009, presumptive cases of malaria among a study population living in a typical Sahelian village of Niger were recorded, and confirmed by microscopic examination. In parallel, asymptomatic carriers were actively detected at the end of each dry season in 2007, 2008 and 2009.

Results

Among the 965 presumptive malaria cases recorded, 29% were confirmed by microscopic examination. The incidence of malaria was found to decrease significantly with age (p < 0.01). The mean annual incidence was 0.254. The results show that the risk of malaria was higher in children under ten years (p < 0.0001). The number of malaria episodes generally followed the temporal pattern of changes in precipitation levels, with a peak of transmission in August and September. One-thousand and ninety subjects were submitted to an active detection of asymptomatic carriage of whom 16% tested positive; asymptomatic carriage decreased with increasing age. A higher prevalence of gametocyte carriage among asymptomatic population was recorded in children aged two to ten years, though it did not reach significance.

Conclusions

In Southern Niger, malaria transmission mostly occurs from July to October. Children aged two to ten years are the most at risk of malaria, and may also represent the main reservoir for gametocytes. Strategies such as intermittent preventive treatment in children (IPTc) could be of interest in this area, where malaria transmission is highly seasonal. Based on these preliminary data, a pilot study could be implemented in Zindarou using IPTc targeting children aged two to ten years, during the three months of malaria transmission, together with an accurate monitoring of drug resistance.

Selective intermittent preventive treatment of vivax malaria: reduction of malaria incidence in an open cohort study in brazilian Amazon

In children, the Intermittent Preventive Treatment (IPTc), currently called Seasonal Malaria Chemoprevention (SMC), was considered effective on malaria control due to the reduction of its incidence in Papua New Guinea and in some areas with seasonal malaria in Africa. However, the IPT has not been indicated because of its association with drug resistance and for hindering natural immunity development. Thus, we evaluated the alternative IPT impact on malaria incidence in three riverside communities on Madeira River, in the municipality of Porto Velho, RO. We denominate this scheme Selective Intermittent Preventive Treatment (SIPT). The SIPT consists in a weekly dose of two 150 mg chloroquine tablets for 12 weeks, for adults, and an equivalent dose for children, after complete supervised treatment for P. vivax infection. This scheme is recommend by Brazilian Health Ministry to avoid frequent relapses. The clinic parasitological and epidemiological surveillance showed a significant reduction on vivax malaria incidence. The results showed a reduction on relapses and recurrence of malaria after SIPT implementation. The SIPT can be effective on vivax malaria control in localities with high transmission risk in the Brazilian Amazon.

Pharmacodynamics of antimalarial chemotherapy

Malaria chemotherapy is under constant threat from the emergence and spread of multidrug resistance of Plasmodium falciparum. Resistance has been observed to almost all currently used antimalarials. Some drugs are also limited by toxicity. A fundamental component of the strategy for malaria chemotherapy is based on prompt, effective and safe antimalarial drugs. To counter the threat of resistance of P. falciparum to existing monotherapeutic regimens, current malaria treatment is based principally on the artemisinin group of compounds, either as monotherapy or artemisinin-based combination therapies for treatment of both uncomplicated and severe falciparum malaria. Key advantages of artemisinins over the conventional antimalarials include their rapid and potent action, with good tolerability profiles. Their action also covers transmissible gametocytes, resulting in decreased disease transmission. Up to now there has been no prominent report of drug resistance to this group of compounds. Treatment of malaria in pregnant women requires special attention in light of limited treatment options caused by potential teratogenicity coupled with a paucity of safety data for the mother and fetus. Treatment of other malaria species is less problematic and chloroquine is still the drug of choice, although resistance of P. vivax to chloroquine has been reported. Multiple approaches to the identification of new antimalarial targets and promising antimalarial drugs are being pursued in order to cope with drug resistance.

Assessment of the molecular marker of Plasmodium falciparum chloroquine resistance (Pfcrt) in Senegal after several years of chloroquine withdrawal

As a result of widespread antimalarial drug resistance, all African countries with endemic malaria have, in recent years, changed their malaria treatment policy. In Senegal, the health authorities changed from chloroquine (CQ) to a combination of sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ) in 2003. Since 2006, the artemisinin combination therapies (ACTs) artemether-lumefantrine (AL) and artesunate plus amodiaquine (AS/AQ) were adopted for uncomplicated malaria treatment. After several years of CQ withdrawal, the current study wished to determine the level of CQ resistance at the molecular level in selected sites in Senegal, because the scientific community is interested in using CQ again. Finger prick blood samples were collected from Plasmodium falciparum-positive children below the age of 10 years (N = 474) during cross-sectional surveys conducted in two study sites in Senegal with different malaria transmission levels. One site is in central Senegal, and the other site is in the southern part of the country. All samples were analyzed for single nucleotide polymorphisms (SNPs) in the P. falciparum CQ resistance transporter gene (Pfcrt; codons 72-76) using polymerase chain reaction (PCR) sequence-specific oligonucleotide probe (SSOP) enzyme-linked immunosorbent assay (ELISA) and real-time PCR methods. In total, the 72- to 76-codon region of Pfcrt was amplified in 449 blood samples (94.7%; 285 and 164 samples from the central and southern sites of Senegal, respectively). In both study areas, the prevalence of the Pfcrt wild-type single CVMNK haplotype was very high; in central Senegal, the prevalence was 70.5% in 2009 and 74.8% in 2010, and in southern Senegal, the prevalence was 65.4% in 2010 and 71.0% in 2011. Comparing data with older studies in Senegal, a sharp decline in the mutant type Pfcrt prevalence is evident: from 65%, 64%, and 59.5% in samples collected from various sites in 2000, 2001, and 2004 to approximately 30% in our study. A similar decrease in mutant type prevalence is noted in other neighboring countries. With the continued development of increased CQ susceptibility in many African countries, it may be possible to reintroduce CQ in the near future in a drug combination; it could possibly be given to non-vulnerable groups, but it demands close monitoring of possible reemergence of CQ resistance development.

Estimating the potential public health impact of seasonal malaria chemoprevention in African children

Seasonal malaria chemoprevention, previously known as intermittent preventive treatment in children, is highly effective in areas with a short malaria transmission season. Here we assess seasonality in malaria incidence data and define a predictor of seasonality based on rainfall. We then use spatial rainfall, malaria endemicity and population data to identify areas likely to have highly seasonal malaria incidence, and estimate the population at risk and malaria burden in areas where seasonal malaria chemoprevention would be appropriate. We estimate that in areas suitable for seasonal malaria chemoprevention, there are 39 million children under 5 years of age, who experience 33.7 million malaria episodes and 152,000 childhood deaths from malaria each year. The majority of this burden occurs in the Sahelian or sub-Sahelian regions of Africa. Our data suggest that seasonal malaria chemoprevention has the potential to avert several million malaria cases and tens of thousands of childhood deaths each year if successfully delivered to the populations at risk.

Seasonal malaria chemoprevention can lower the incidence of malaria in areas where transmission is highly periodical. Combining data on rainfall, population and malaria endemicity, Cairns et al. identify geographical areas in sub-Saharan Africa where this intervention is likely to be effective and cost-effective.

Intermittent preventive treatment for malaria in children living in areas with seasonal transmission

BACKGROUND

In malaria endemic areas, pre-school children are at high risk of severe and repeated malaria illness. One possible public health strategy, known as Intermittent Preventive Treatment in children (IPTc), is to treat all children for malaria at regular intervals during the transmission season, regardless of whether they are infected or not.

OBJECTIVES

To evaluate the effects of IPTc to prevent malaria in preschool children living in endemic areas with seasonal malaria transmission.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register (July 2011), CENTRAL (The Cochrane Library 2011, Issue 6), MEDLINE (1966 to July 2011), EMBASE (1974 to July 2011), LILACS (1982 to July 2011), mRCT (July 2011), and reference lists of identified trials. We also contacted researchers working in the field for unpublished and ongoing trials.

SELECTION CRITERIA

Individually randomized and cluster-randomized controlled trials of full therapeutic dose of antimalarial or antimalarial drug combinations given at regular intervals compared with placebo or no preventive treatment in children aged six years or less living in an area with seasonal malaria transmission.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility, extracted data and assessed the risk of bias in the trials. Data were meta-analysed and measures of effects (ie rate ratio, risk ratio and mean difference) are presented with 95% confidence intervals (CIs). The quality of evidence was assessed using the GRADE methods.

MAIN RESULTS

Seven trials (12,589 participants), including one cluster-randomized trial, met the inclusion criteria. All were conducted in West Africa, and six of seven trials were restricted to children aged less than 5 years.IPTc prevents approximately three quarters of all clinical malaria episodes (rate ratio 0.26; 95% CI 0.17 to 0.38; 9321 participants, six trials, high quality evidence), and a similar proportion of severe malaria episodes (rate ratio 0.27, 95% CI 0.10 to 0.76; 5964 participants, two trials, high quality evidence). These effects remain present even where insecticide treated net (ITN) usage is high (two trials, 5964 participants, high quality evidence).IPTc probably produces a small reduction in all-cause mortality consistent with the effect on severe malaria, but the trials were underpowered to reach statistical significance (risk ratio 0.66, 95% CI 0.31 to 1.39, moderate quality evidence).The effect on anaemia varied between studies, but the risk of moderately severe anaemia is probably lower with IPTc (risk ratio 0.71, 95% CI 0.52 to 0.98; 8805 participants, five trials, moderate quality evidence).Serious drug-related adverse events, if they occur, are probably rare, with none reported in the six trials (9533 participants, six trials, moderate quality evidence). Amodiaquine plus sulphadoxine-pyrimethamine is the most studied drug combination for seasonal chemoprevention. Although effective, it causes increased vomiting in this age-group (risk ratio 2.78, 95% CI 2.31 to 3.35; two trials, 3544 participants, high quality evidence).When antimalarial IPTc was stopped, no rebound increase in malaria was observed in the three trials which continued follow-up for one season after IPTc.

AUTHORS' CONCLUSIONS

In areas with seasonal malaria transmission, giving antimalarial drugs to preschool children (age < 6 years) as IPTc during the malaria transmission season markedly reduces episodes of clinical malaria, including severe malaria. This benefit occurs even in areas where insecticide treated net usage is high.

Combination of probenecid-sulphadoxine-pyrimethamine for intermittent preventive treatment in pregnancy

The antifolate sulphadoxine-pyrimethamine (SP) has been used in the intermittent prevention of malaria in pregnancy (IPTp). SP is an ideal choice for IPTp, however, as resistance of Plasmodium falciparum to SP increases, data are accumulating that SP may no longer provide benefit in areas of high-level resistance. Probenecid was initially used as an adjunctive therapy to increase the blood concentration of penicillin; it has since been used to augment concentrations of other drugs, including antifolates. The addition of probenecid has been shown to increase the treatment efficacy of SP against malaria, suggesting that the combination of probenecid plus SP may prolong the useful lifespan of SP as an effective agent for IPTp. Here, the literature on the pharmacokinetics, adverse reactions, interactions and available data on the use of these drugs in pregnancy is reviewed, and the possible utility of an SP-probenecid combination is discussed. This article concludes by calling for further research into this potentially useful combination.

Impact of combining intermittent preventive treatment with home management of malaria in children less than 10 years in a rural area of Senegal: a cluster randomized trial

BACKGROUND

Current malaria control strategies recommend (i) early case detection using rapid diagnostic tests (RDT) and treatment with artemisinin combination therapy (ACT), (ii) pre-referral rectal artesunate, (iii) intermittent preventive treatment and (iv) impregnated bed nets. However, these individual malaria control interventions provide only partial protection in most epidemiological situations. Therefore, there is a need to investigate the potential benefits of integrating several malaria interventions to reduce malaria prevalence and morbidity.

METHODS

A randomized controlled trial was carried out to assess the impact of combining seasonal intermittent preventive treatment in children (IPTc) with home-based management of malaria (HMM) by community health workers (CHWs) in Senegal. Eight CHWs in eight villages covered by the Bonconto health post, (South Eastern part of Senegal) were trained to diagnose malaria using RDT, provide prompt treatment with artemether-lumefantrine for uncomplicated malaria cases and pre-referral rectal artesunate for complicated malaria occurring in children under 10 years. Four CHWs were randomized to also administer monthly IPTc as single dose of sulphadoxine-pyrimethamine (SP) plus three doses of amodiaquine (AQ) in the malaria transmission season, October and November 2010. Primary end point was incidence of single episode of malaria attacks over 8 weeks of follow up. Secondary end points included prevalence of malaria parasitaemia, and prevalence of anaemia at the end of the transmission season. Primary analysis was by intention to treat. The study protocol was approved by the Senegalese National Ethical Committee (approval 0027/MSP/DS/CNRS, 18/03/2010).

RESULTS

A total of 1,000 children were enrolled. The incidence of malaria episodes was 7.1/100 child months at risk [95% CI (3.7-13.7)] in communities with IPTc + HMM compared to 35.6/100 child months at risk [95% CI (26.7-47.4)] in communities with only HMM (aOR = 0.20; 95% CI 0.09-0.41; p = 0.04). At the end of the transmission season, malaria parasitaemia prevalence was lower in communities with IPTc + HMM (2.05% versus 4.6% p = 0.03). Adjusted for age groups, sex, Plasmodium falciparum carriage and prevalence of malnutrition, IPTc + HMM showed a significant protective effect against anaemia (aOR = 0.59; 95% CI 0.42-0.82; p = 0.02).

CONCLUSION

Combining IPTc and HMM can provide significant additional benefit in preventing clinical episodes of malaria as well as anaemia among children in Senegal.

Effects of amodiaquine and artesunate on sulphadoxine-pyrimethamine pharmacokinetic parameters in children under five in Mali

BACKGROUND

Sulphadoxine-pyrimethamine, in combination with artesunate or amodiaquine, is recommended for the treatment of uncomplicated malaria and is being evaluated for intermittent preventive treatment. Yet, limited data is available on pharmacokinetic interactions between these drugs.

METHODS

In a randomized controlled trial, children aged 6-59 months with uncomplicated falciparum malaria, received either one dose of sulphadoxine-pyrimethamine alone (SP), one dose of SP plus three daily doses of amodiaquine (SP+AQ) or one dose of SP plus 3 daily doses of artesunate (SP+AS). Exactly 100 μl of capillary blood was collected onto filter paper before drug administration at day 0 and at days 1, 3, 7, 14, 21 and 28 after drug administration for analysis of sulphadoxine and pyrimethamine pharmacokinetic parameters.

RESULTS

Fourty, 38 and 31 patients in the SP, SP+AQ and SP+AS arms, respectively were included in this study. The concentrations on day 7 (that are associated with therapeutic efficacy) were similar between the SP, SP+AQ and SP+AS treatment arms for sulphadoxine (median [IQR] 35.25 [27.38-41.70], 34.95 [28.60-40.85] and 33.40 [24.63-44.05] μg/mL) and for pyrimethamine (56.75 [46.40-92.95], 58.75 [43.60-98.60] and 59.60 [42.45-86.63] ng/mL). There were statistically significant differences between the pyrimethamine volumes of distribution (4.65 [3.93-6.40], 4.00 [3.03-5.43] and 5.60 [4.40-7.20] L/kg; p = 0.001) and thus elimination half-life (3.26 [2.74 -3.82], 2.78 [2.24-3.65] and 4.02 [3.05-4.85] days; p < 0.001). This study confirmed the lower SP concentrations previously reported for young children when compared with adult malaria patients.

CONCLUSION

Despite slight differences in pyrimethamine volumes of distribution and elimination half-life, these data show similar exposure to SP over the critical initial seven days of treatment and support the current use of SP in combination with either AQ or AS for uncomplicated falciparum malaria treatment in young Malian children.

Cost analysis of school-based intermittent screening and treatment of malaria in Kenya

Background

The control of malaria in schools is receiving increasing attention, but there remains currently no consensus as to the optimal intervention strategy. This paper analyses the costs of intermittent screening and treatment (IST) of malaria in schools, implemented as part of a cluster-randomized controlled trial on the Kenyan coast.

Methods

Financial and economic costs were estimated using an ingredients approach whereby all resources required in the delivery of IST are quantified and valued. Sensitivity analysis was conducted to investigate how programme variation affects costs and to identify potential cost savings in the future implementation of IST.

Results

The estimated financial cost of IST per child screened is US$ 6.61 (economic cost US$ 6.24). Key contributors to cost were salary costs (36%) and malaria rapid diagnostic tests (RDT) (22%). Almost half (47%) of the intervention cost comprises redeployment of existing resources including health worker time and use of hospital vehicles. Sensitivity analysis identified changes to intervention delivery that can reduce programme costs by 40%, including use of alternative RDTs and removal of supervised treatment. Cost-effectiveness is also likely to be highly sensitive to the proportion of children found to be RDT-positive.

Conclusion

In the current context, school-based IST is a relatively expensive malaria intervention, but reducing the complexity of delivery can result in considerable savings in the cost of intervention.

(Costs are reported in US$ 2010).

Malaria morbidity in children in the year after they had received intermittent preventive treatment of malaria in Mali: a randomized control trial

BACKGROUND

Intermittent preventive treatment of malaria in children (IPTc) is a promising strategy for malaria control. A study conducted in Mali in 2008 showed that administration of three courses of IPTc with sulphadoxine-pyrimethamine (SP) and amodiaquine (AQ) at monthly intervals reduced clinical malaria, severe malaria and malaria infection by >80% in children under 5 years of age. Here we report the results of a follow-on study undertaken to establish whether children who had received IPTc would be at increased risk of malaria during the subsequent malaria transmission season.

METHODS

Morbidity from malaria and the prevalence of malaria parasitaemia and anaemia were measured in children who had previously received IPTc with SP and AQ using similar surveillance methods to those employed during the previous intervention period.

RESULTS

1396 of 1508 children (93%) who had previously received IPTc and 1406 of 1508 children (93%) who had previously received placebos were followed up during the high malaria transmission season of the year following the intervention. Incidence rates of clinical malaria during the post-intervention transmission season (July-November 2009) were 1.87 (95% CI 1.76-1.99) and 1.73 (95% CI; 1.62-1.85) episodes per child year in the previous intervention and placebo groups respectively; incidence rate ratio (IRR) 1.09 (95% CI 0.99-1.21) (P = 0.08). The prevalence of malaria infection was similar in the two groups, 7.4% versus 7.5%, prevalence ratio (PR) of 0.99 (95% CI 0.73-1.33) (P = 0.95). At the end of post-intervention malaria transmission season, the prevalence of anaemia, defined as a haemoglobin concentration<11g/dL, was similar in the two groups (56.2% versus 55.6%; PR = 1.01 [95% CI 0.91-1.12]) (P = 0.84).

CONCLUSION

IPTc with SP+AQ was not associated with an increase in incidence of malaria episodes, prevalence of malaria infection or anaemia in the subsequent malaria transmission season.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00738946.

Morbidity from malaria in children in the year after they had received intermittent preventive treatment of malaria: a randomised trial

BACKGROUND

Interventions that reduce exposure to malaria infection may lead to delayed malaria morbidity and mortality. We investigated whether intermittent preventive treatment of malaria in children (IPTc) was associated with an increase in the incidence of malaria after cessation of the intervention.

METHODS

An individually randomised, trial of IPTc, comparing three courses of sulphadoxine pyrimethamine (SP) plus amodiaquine (AQ) with placebos was implemented in children aged 3-59 months during the 2008 malaria transmission season in Burkina Faso. All children in the trial were given a long lasting insecticide treated net; 1509 children received SP+AQ and 1505 received placebos. Passive surveillance for malaria was maintained until the end of the subsequent malaria transmission season in 2009, and active surveillance for malaria infection, anaemia and malnutrition was conducted.

RESULTS

On thousand, four hundred and sixteen children (93.8%) and 1399 children (93.0%) initially enrolled in the intervention and control arms of the trial respectively were followed during the 2009 malaria transmission season. During the period July 2009 to November 2009, incidence rates of clinical malaria were 3.84 (95%CI; 3.67-4.02) and 3.45 (95%CI; 3.29-3.62) episodes per child during the follow up period in children who had previously received IPT or placebos, indicating a small increase in risk for children in the former intervention arm (IRR = 1.12; 95%CI 1.04-1.20) (P = 0.003). Children who had received SP+AQ had a lower prevalence of malaria infection (adjusted PR: 0.88 95%CI: 0.79-0.98) (P = 0.04) but they had a higher parasite density (P = 0.001) if they were infected. There was no evidence that the risks of moderately severe anaemia (Hb<8 g/dL), wasting, stunting, or of being underweight in children differed between treatment arms.

CONCLUSION

IPT with SP+AQ was associated with a small increase in the incidence of clinical malaria in the subsequent malaria transmission season.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00738946.

Combining community case management and intermittent preventive treatment for malaria

Employment of members of the community to treat malaria is a promising approach to the management of this infection in areas where access to treatment is difficult. Intermittent preventive treatment (IPT) of malaria has recently been shown to be a highly effective way of reducing morbidity from malaria in children living in areas of seasonal malaria transmission, and it can be delivered efficiently by community volunteers. Therefore, we suggest that in areas where malaria transmission is seasonal, and IPT an appropriate malaria intervention in children, community volunteers could be employed to deliver IPT during the peak malaria-transmission season and also to provide community case management during this period and during the rest of the year when occasional cases of malaria continue to occur.

Increase in EPI vaccines coverage after implementation of intermittent preventive treatment of malaria in infant with Sulfadoxine -pyrimethamine in the district of Kolokani, Mali: results from a cluster randomized control trial

BACKGROUND

Even though the efficacy of Intermittent Preventive Treatment in infants (IPTi) with Sulfadoxine-Pyrimethamine (SP) against clinical disease and the absence of its interaction with routine vaccines of the Expanded Immunization Programme (EPI) have been established, there are still some concerns regarding the addition of IPTi, which may increase the work burden and disrupt the routine EPI services especially in Africa where the target immunization coverage remains to be met. However IPTi may also increase the adherence of the community to EPI services and improve EPI coverage, once the benefice of strategy is perceived.

METHODS

To assess the impact of IPTi implementation on the coverage of EPI vaccines, 22 health areas of the district of Kolokani were randomized at a 1:1 ratio to either receive IPTi-SP or to serve as a control. The EPI vaccines coverage was assessed using cross-sectional surveys at baseline in November 2006 and after one year of IPTi pilot-implementation in December 2007.

RESULTS

At baseline, the proportion of children of 9-23 months who were completely vaccinated (defined as children who received BGG, 3 doses of DTP/Polio, measles and yellow fever vaccines) was 36.7% (95% CI 25.3% -48.0%). After one year of implementation of IPTi-SP using routine health services, the proportion of children completely vaccinated rose to 53.8% in the non intervention zone and 69.5% in the IPTi intervention zone (P <0.001).The proportion of children in the target age groups who received IPTi with each of the 3 vaccinations DTP2, DTP3 and Measles, were 89.2% (95% CI 85.9%-92.0%), 91.0% (95% CI 87.6% -93.7%) and 77.4% (95% CI 70.7%-83.2%) respectively. The corresponding figures in non intervention zone were 2.3% (95% CI 0.9% -4.7%), 2.6% (95% CI 1.0% -5.6%) and 1.7% (95% CI 0.4% - 4.9%).

CONCLUSION

This study shows that high coverage of the IPTi can be obtained when the strategy is implemented using routine health services and implementation results in a significant increase in coverage of EPI vaccines in the district of Kolokani, Mali.

Two-year evaluation of Intermittent Preventive Treatment for Children (IPTc) combined with timely home treatment for malaria control in Ghana

Background

Intermittent preventive treatment (IPT) has recently been accepted as an important component of the malaria control strategy. Intermittent preventive treatment for children (IPTc) combined with timely treatment of malaria related febrile illness at home to reduce parasite prevalence and malaria morbidity in children aged between six and 60 months in a coastal community in Ghana. This paper reports persistence of reduced parasitaemia two years into the intervention. The baseline and year-one-evaluation findings were published earlier.

Objective

The main objective in the second year was to demonstrate whether the two interventions would further reduce parasite prevalence and malaria-related febrile illness in the study population.

Methods

This was an intervention study designed to compare baseline and evaluation findings without a control group. The study combined home-based delivery of intermittent preventive treatment for children (IPTc) aged 6 - 60 months and home treatment of suspected febrile malaria-related illness within 24 hours. All children aged 6 - 60 months received home-based delivery of intermittent preventive treatment using amodiaquine + artesunate, delivered at home by community assistants every four months (6 times in 24 months). Malaria parasite prevalence surveys were conducted before the first and after the third and sixth IPTc to the children. The evaluation surveys were done four months after the third and sixth IPTc was given.

Results

Parasite prevalence which reduced from 25% to 3.0% at year-one evaluation had reduced further from 3% to 1% at year-two-evaluation. At baseline, 13.8% of the children were febrile (axilary temperature of ≥37.5°C) compared to 2.2% at year-one-evaluation while 2.1% were febrile at year-two-evaluation.

Conclusion

The year-two-evaluation result indicates that IPTc given three times in a year (every four months) combined with timely treatment of febrile malaria illness, is effective to reduce malaria parasite prevalence in children aged 6 to 60 months in the study community. This must give hope to malaria control programme managers in sub-Saharan Africa where the burden of the disease is most debilitating.

Modelling the protective efficacy of alternative delivery schedules for intermittent preventive treatment of malaria in infants and children

Background

Intermittent preventive treatment in infants (IPTi) with sulfadoxine-pyrimethamine (SP) is recommended by WHO where malaria incidence in infancy is high and SP resistance is low. The current delivery strategy is via routine Expanded Program on Immunisation contacts during infancy (EPI-IPTi). However, improvements to this approach may be possible where malaria transmission is seasonal, or where the malaria burden lies mainly outside infancy.

Methods and Findings

A mathematical model was developed to estimate the protective efficacy (PE) of IPT against clinical malaria in children aged 2-24 months, using entomological and epidemiological data from an EPI-IPTi trial in Navrongo, Ghana to parameterise the model. The protection achieved by seasonally-targeted IPT in infants (sIPTi), seasonal IPT in children (sIPTc), and by case-management with long-acting artemisinin combination therapies (LA-ACTs) was predicted for Navrongo and for sites with different transmission intensity and seasonality. In Navrongo, the predicted PE of sIPTi was 26% by 24 months of age, compared to 16% with EPI-IPTi. sIPTc given to all children under 2 years would provide PE of 52% by 24 months of age. Seasonally-targeted IPT retained its advantages in a range of transmission patterns. Under certain circumstances, LA-ACTs for case-management may provide similar protection to EPI-IPTi. However, EPI-IPTi or sIPT combined with LA-ACTs would be substantially more protective than either strategy used alone.

Conclusion

Delivery of IPT to infants via the EPI is sub-optimal because individuals are not protected by IPT at the time of highest malaria risk, and because older children are not protected. Alternative delivery strategies to the EPI are needed where transmission varies seasonally or the malaria burden extends beyond infancy. Long-acting ACTs may also make important reductions in malaria incidence. However, delivery systems must be developed to ensure that both forms of chemoprevention reach the individuals who are most exposed to malaria.

Determinants of the cost-effectiveness of intermittent preventive treatment for malaria in infants and children

BACKGROUND

Trials of intermittent preventive treatment in infants (IPTi) and children (IPTc) have shown promising results in reducing malaria episodes but with varying efficacy and cost-effectiveness. The effects of different intervention and setting characteristics are not well known. We simulate the effects of the different target age groups and delivery channels, seasonal or year-round delivery, transmission intensity, seasonality, proportions of malaria fevers treated and drug characteristics.

METHODS

We use a dynamic, individual-based simulation model of Plasmodium falciparum malaria epidemiology, antimalarial drug action and case management to simulate DALYs averted and the cost per DALY averted by IPTi and IPTc. IPT cost components were estimated from economic studies alongside trials.

RESULTS

IPTi and IPTc were predicted to be cost-effective in most of the scenarios modelled. The cost-effectiveness is driven by the impact on DALYs, particularly for IPTc, and the low costs, particularly for IPTi which uses the existing delivery strategy, EPI. Cost-effectiveness was predicted to decrease with low transmission, badly timed seasonal delivery in a seasonal setting, short-acting and more expensive drugs, high frequencies of drug resistance and high levels of treatment of malaria fevers. Seasonal delivery was more cost-effective in seasonal settings, and year-round in constant transmission settings. The difference was more pronounced for IPTc than IPTi due to the different proportions of fixed costs and also different assumed drug spacing during the transmission season. The number of DALYs averted was predicted to decrease as a target five-year age-band for IPTc was shifted from children under 5 years into older ages, except at low transmission intensities.

CONCLUSIONS

Modelling can extend the information available by predicting impact and cost-effectiveness for scenarios, for outcomes and for multiple strategies where, for practical reasons, trials cannot be carried out. Both IPTi and IPTc are generally cost-effective but could be rendered cost-ineffective by characteristics of the setting, drug or implementation.

A systematic review and meta-analysis of the efficacy and safety of intermittent preventive treatment of malaria in children (IPTc)

BACKGROUND

Intermittent preventive treatment of malaria in children less than five years of age (IPTc) has been investigated as a measure to control the burden of malaria in the Sahel and sub-Sahelian areas of Africa where malaria transmission is markedly seasonal.

METHODS AND FINDINGS

IPTc studies were identified using a systematic literature search. Meta-analysis was used to assess the protective efficacy of IPTc against clinical episodes of falciparum malaria. The impact of IPTc on all-cause mortality, hospital admissions, severe malaria and the prevalence of parasitaemia and anaemia was investigated. Three aspects of safety were also assessed: adverse reactions to study drugs, development of drug resistance and loss of immunity to malaria. Twelve IPTc studies were identified: seven controlled and five non-controlled trials. Controlled studies demonstrated protective efficacies against clinical malaria of between 31% and 93% and meta-analysis gave an overall protective efficacy of monthly administered IPTc of 82% (95%CI 75%-87%) during the malaria transmission season. Pooling results from twelve studies demonstrated a protective effect of IPTc against all-cause mortality of 57% (95%CI 24%-76%) during the malaria transmission season. No serious adverse events attributable to the drugs used for IPTc were observed in any of the studies. Data from three studies that followed children during the malaria transmission season in the year following IPTc administration showed evidence of a slight increase in the incidence of clinical malaria compared to children who had not received IPTc.

CONCLUSIONS

IPTc is a safe method of malaria control that has the potential to avert a significant proportion of clinical malaria episodes in areas with markedly seasonal malaria transmission and also appears to have a substantial protective effect against all-cause mortality. These findings indicate that IPTc is a potentially valuable tool that can contribute to the control of malaria in areas with markedly seasonal transmission.