Low COVID-19 vaccine uptake in people living with HIV and those with hypertension and diabetes without HIV at Mbarara and Masaka regional referral hospitals: A cross-sectional survey

Chronic diseases such as HIV, hypertension, and diabetes increase the risk of severe coronavirus disease 2019 (COVID-19) and death. Thus, COVID-19 vaccine uptake data among these priority populations are needed to inform immunization programs. We assessed COVID-19 vaccine uptake among people living with HIV (PLWH) and those with hypertension/diabetes without HIV (PWoH) in Southwestern and Southcentral Uganda and determined factors influencing vaccination. We conducted a cross-sectional study from January to April 2023. We enrolled a random sample of participants aged 18 years and older seeking HIV, hypertension, or diabetes care at two regional referral hospitals (RRHs) in Mbarara and Masaka in Uganda. Using vaccination records abstraction and interviewer-administered questionnaires, we collected data on COVID-19 vaccine uptake, sociodemographic data, and reasons for non-uptake in unvaccinated persons. We compared COVID-19 vaccination uptake between PLWH and PWoH and applied modified Poisson regression to determine sociodemographic factors associated with vaccine uptake. The reasons for non-vaccine uptake were presented as percentages. Of the 1,376 enrolled participants, 65.6% were fully vaccinated against COVID-19. Vaccination coverage was 65% among PWLH versus 67% among PWoH. Higher education attainment and older age were associated with COVID vaccination. Participants with secondary education and those aged ≥50 years achieved >70% coverage. Fear of side effects was the most cited reason (67%) for non-vaccination among 330 unvaccinated participants, followed by vaccine mistrust (24.5%). People with chronic diseases in Southwestern Uganda had slightly lower than 70% COVID-19 vaccine coverage as recommended by WHO. Higher educational attainment and older age were linked to increased vaccine uptake. However, mistrust and fear of vaccine side effects were the main reasons for non-vaccination. To increase COVID-19 vaccine uptake, programs must reach those with lower educational attainment and younger age groups, and address the fear of vaccine side effects and mistrust among persons with underlying diseases in Uganda.

Monthly Sulfadoxine-Pyrimethamine During Pregnancy Prevents Febrile Respiratory Illnesses: A Secondary Analysis of a Malaria Chemoprevention Trial in Uganda

Background

Trials evaluating antimalarials for intermittent preventive treatment in pregnancy (IPTp) have shown that dihydroartemisinin-piperaquine (DP) is a more efficacious antimalarial than sulfadoxine-pyrimethamine (SP); however, SP is associated with higher birthweight, suggesting that SP demonstrates "nonmalarial" effects. Chemoprevention of nonmalarial febrile illnesses (NMFIs) was explored as a possible mechanism.

Methods

In this secondary analysis, we leveraged data from 654 pregnant Ugandan women without HIV infection who participated in a randomized controlled trial comparing monthly IPTp-SP with IPTp-DP. Women were enrolled between 12 and 20 gestational weeks and followed through delivery. NMFIs were measured by active and passive surveillance and defined by the absence of malaria parasitemia. We quantified associations among IPTp regimens, incident NMFIs, antibiotic prescriptions, and birthweight.

Results

Mean "birthweight for gestational age" Z scores were 0.189 points (95% CI, .045-.333) higher in women randomized to IPTp-SP vs IPTp-DP. Women randomized to IPTp-SP had fewer incident NMFIs (incidence rate ratio, 0.74; 95% CI, .58-.95), mainly respiratory NMFIs (incidence rate ratio, 0.69; 95% CI, .48-1.00), vs IPTp-DP. Counterintuitively, respiratory NMFI incidence was positively correlated with birthweight in multigravidae. In total 75% of respiratory NMFIs were treated with antibiotics. Although overall antibiotic prescriptions were similar between arms, for each antibiotic prescribed, "birthweight for gestational age" Z scores increased by 0.038 points (95% CI, .001-.074).

Conclusions

Monthly IPTp-SP was associated with reduced respiratory NMFI incidence, revealing a potential nonmalarial mechanism of SP and supporting current World Health Organization recommendations for IPTp-SP, even in areas with high-grade SP resistance. While maternal respiratory NMFIs are known risk factors of lower birthweight, most women in our study were presumptively treated with antibiotics, masking the potential benefit of SP on birthweight mediated through preventing respiratory NMFIs.

Seasonal Malaria Chemoprevention Drug Levels and Drug Resistance Markers in Children With or Without Malaria in Burkina Faso: A Case-Control Study

BACKGROUND

Despite scale-up of seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SP-AQ) in children 3-59 months of age in Burkina Faso, malaria incidence remains high, raising concerns regarding SMC effectiveness and selection of drug resistance. Using a case-control design, we determined associations between SMC drug levels, drug resistance markers, and presentation with malaria.

METHODS

We enrolled 310 children presenting at health facilities in Bobo-Dioulasso. Cases were SMC-eligible children 6-59 months of age diagnosed with malaria. Two controls were enrolled per case: SMC-eligible children without malaria; and older (5-10 years old), SMC-ineligible children with malaria. We measured SP-AQ drug levels among SMC-eligible children and SP-AQ resistance markers among parasitemic children. Conditional logistic regression was used to compute odds ratios (ORs) comparing drug levels between cases and controls.

RESULTS

Compared to SMC-eligible controls, children with malaria were less likely to have any detectable SP or AQ (OR, 0.33 [95% confidence interval, .16-.67]; P = .002) and have lower drug levels (P < .05). Prevalences of mutations mediating high-level SP resistance were rare (0%-1%) and similar between cases and SMC-ineligible controls (P > .05).

CONCLUSIONS

Incident malaria among SMC-eligible children was likely due to suboptimal levels of SP-AQ, resulting from missed cycles rather than increased antimalarial resistance to SP-AQ.

Testing and treatment for malaria elimination: a systematic review

BACKGROUND

Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies.

METHODS

A systematic review and meta-analysis were conducted to assess the effectiveness of TaT strategies to reduce malaria transmission.

RESULTS

A total of 72 empirical research and 24 modelling studies were identified, mainly focused on proactive mass TaT (MTaT) and reactive case detection (RACD) in higher and lower transmission settings, respectively. Ten intervention studies compared MTaT to no MTaT and the evidence for impact on malaria incidence was weak. No intervention studies compared RACD to no RACD. Compared to passive case detection (PCD) alone, PCD + RACD using standard diagnostics increased infection detection 52.7% and 11.3% in low and very low transmission settings, respectively. Using molecular methods increased this detection of infections by 1.4- and 1.1-fold, respectively.

CONCLUSION

Results suggest MTaT is not effective for reducing transmission. By increasing case detection, surveillance data provided by RACD may indirectly reduce transmission by informing coordinated responses of intervention targeting.

Effect of the COVID-19 lockdown on the HIV care continuum in Southwestern Uganda: A time series analysis

INTRODUCTION

In Uganda, COVID-19 lockdown policies curbed the spread of SARS-CoV-2, but their effect on HIV care is poorly understood.

OBJECTIVES

We examined the effects of COVID-19 lockdown policies on ART initiation, missed visits, and viral suppression in Uganda.

METHODS

We conducted a time series analysis using data from a dynamic cohort of persons with HIV enrolled between March 2017 and September 2021 at HIV clinics in Masaka and Mbarara Regional Referral Hospitals in Southwestern Uganda. Poisson and fractional probit regression were used to predict expected monthly antiretroviral therapy initiations, missed visits, and viral suppression based on pre-lockdown trends. Observed and expected trends were compared across three policy periods: April 2020-September 2021 (overall), April-May 2020 (1st lockdown), and June-August 2021 (2nd lockdown).

RESULTS

We enrolled 7071 Persons living with HIV (PWH) (nMasaka = 4150; nMbarara = 2921). Average ART duration was 34 and 30 months in Masaka and Mbarara, respectively. During the 18-month post-lockdown period, monthly ART initiations were lower than expected in both Masaka (51 versus 63 visits; a decrease of 12 [95% CI: -2, 31] visits) and Mbarara (42 versus 55 visits; a decrase of 13 [95% CI: 0, 27] visits). Proportion of missed visits was moderately higher than expected post-lockdown in Masaka (10% versus 7%; 4% [95% CI: 1%, 7%] absolute increase), but not in Mbarara (13% versus 13%; 0% [95% CI: -4%, 6%] absolute decrease). Viral suppression rates were moderate-to-high in Masaka (64.7%) and Mbarara (92.5%) pre-lockdown and remained steady throughout the post-lockdown period.

CONCLUSION

The COVID-19 lockdown in Uganda was associated with reductions in ART initiation, with minimal effects on retention and viral suppression, indicating a resilient HIV care system.

Association between indoor residual spraying and pregnancy outcomes: a quasi-experimental study from Uganda

BACKGROUND

Malaria is a risk factor for adverse pregnancy outcomes. Indoor residual spraying with insecticide (IRS) reduces malaria infections, yet the effects of IRS on pregnancy outcomes are not well established. We evaluated the impact of a large-scale IRS campaign on pregnancy outcomes in Eastern Uganda.

METHODS

Birth records (n = 59 992) were obtained from routine surveillance data at 25 health facilities from five districts that were part of the IRS campaign and six neighbouring control districts ∼27 months before and ∼24 months after the start of the campaign (January 2013-May 2017). Campaign effects on low birthweight (LBW) and stillbirth incidence were estimated using the matrix completion method (MC-NNM), a machine-learning approach to estimating potential outcomes, and compared with the difference-in-differences (DiD) estimator. Subgroup analyses were conducted by HIV and gravidity.

RESULTS

MC-NNM estimates indicated that the campaign was associated with a 33% reduction in LBW incidence: incidence rate ratio (IRR) = 0.67 [95% confidence interval (CI): 0.49-0.93)]. DiD estimates were similar to MC-NNM [IRR = 0.69 (0.47-1.01)], despite a parallel trends violation during the pre-IRS period. The campaign was not associated with substantial reductions in stillbirth incidence [IRRMC-NNM = 0.94 (0.50-1.77)]. HIV status modified the effects of the IRS campaign on LBW [βIRSxHIV = 0.42 (0.05-0.78)], whereby HIV-negative women appeared to benefit from the campaign [IRR = 0.70 (0.61-0.81)], but not HIV-positive women [IRR = 1.12 (0.59-2.12)].

CONCLUSIONS

Our results support the effectiveness of the campaign in Eastern Uganda based on its benefit to LBW prevention, though HIV-positive women may require additional interventions. The IRS campaign was not associated with a substantively lower stillbirth incidence, warranting further research.

Impact of COVID-19 on routine malaria indicators in rural Uganda: an interrupted time series analysis

Background

In March 2020, the government of Uganda implemented a strict lockdown policy in response to the COVID-19 pandemic. Interrupted time series analysis (ITSA) was performed to assess whether major changes in outpatient attendance, malaria burden, and case management occurred after the onset of the COVID-19 epidemic in rural Uganda.

Methods

Individual level data from all outpatient visits collected from April 2017 to March 2021 at 17 facilities were analysed. Outcomes included total outpatient visits, malaria cases, non-malarial visits, proportion of patients with suspected malaria, proportion of patients tested using rapid diagnostic tests (RDTs), and proportion of malaria cases prescribed artemether-lumefantrine (AL). Poisson regression with generalized estimating equations and fractional regression was used to model count and proportion outcomes, respectively. Pre-COVID trends (April 2017-March 2020) were used to predict the’expected’ trend in the absence of COVID-19 introduction. Effects of COVID-19 were estimated over two six-month COVID-19 time periods (April 2020-September 2020 and October 2020–March 2021) by dividing observed values by expected values, and expressed as ratios.

Results

A total of 1,442,737 outpatient visits were recorded. Malaria was suspected in 55.3% of visits and 98.8% of these had a malaria diagnostic test performed. ITSA showed no differences between observed and expected total outpatient visits, malaria cases, non-malarial visits, or proportion of visits with suspected malaria after COVID-19 onset. However, in the second six months of the COVID-19 time period, there was a smaller mean proportion of patients tested with RDTs compared to expected (relative prevalence ratio (RPR) = 0.87, CI (0.78–0.97)) and a smaller mean proportion of malaria cases prescribed AL (RPR = 0.94, CI (0.90–0.99)).

Conclusions

In the first year after the COVID-19 pandemic arrived in Uganda, there were no major effects on malaria disease burden and indicators of case management at these 17 rural health facilities, except for a modest decrease in the proportion of RDTs used for malaria diagnosis and the mean proportion of malaria cases prescribed AL in the second half of the COVID-19 pandemic year. Continued surveillance will be essential to monitor for changes in trends in malaria indicators so that Uganda can quickly and flexibly respond to challenges imposed by COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04018-0.

Civilian-military malaria outbreak response in Thailand: an example of multi-stakeholder engagement for malaria elimination

BACKGROUND

In April 2017, the Thai Ministry of Public Health (MoPH) was alerted to a potential malaria outbreak among civilians and military personnel in Sisaket Province, a highly forested area bordering Cambodia. The objective of this study was to present findings from the joint civilian-military outbreak response.

METHODS

A mixed-methods approach was used to assess risk factors among cases reported during the 2017 Sisaket malaria outbreak. Routine malaria surveillance data from January 2013 to March 2018 obtained from public and military medical reporting systems and key informant interviews (KIIs) (n = 72) were used to develop hypotheses about potential factors contributing to the outbreak. Joint civilian-military response activities included entomological surveys, mass screen and treat (MSAT) and vector control campaigns, and scale-up of the "1-3-7" reactive case detection approach among civilians alongside a pilot "1-3-7" study conducted by the Royal Thai Army (RTA).

RESULTS

Between May-July 2017, the monthly number of MoPH-reported cases surpassed the epidemic threshold. Outbreak cases detected through the MoPH mainly consisted of Thai males (87%), working as rubber tappers (62%) or military/border police (15%), and Plasmodium vivax infections (73%). Compared to cases from the previous year (May-July 2016), outbreak cases were more likely to be rubber tappers (OR = 14.89 [95% CI: 5.79-38.29]; p < 0.001) and infected with P. vivax (OR=2.32 [1.27-4.22]; p = 0.006). Themes from KIIs were congruent with findings from routine surveillance data. Though limited risk factor information was available from military cases, findings from RTA's "1-3-7" study indicated transmission was likely occurring outside military bases. Data from entomological surveys and MSAT campaigns support this hypothesis, as vectors were mostly exophagic and parasite prevalence from MSAT campaigns was very low (range: 0-0.7% by PCR/microscopy).

CONCLUSIONS

In 2017, an outbreak of mainly P. vivax occurred in Sisaket Province, affecting mainly military and rubber tappers. Vector control use was limited to the home/military barracks, indicating that additional interventions were needed during high-risk forest travel periods. Importantly, this outbreak catalyzed joint civilian-military collaborations and integration of the RTA into the national malaria elimination strategy (NMES). The Sisaket outbreak response serves as an example of how civilian and military public health systems can collaborate to advance national malaria elimination goals in Southeast Asia and beyond.

Marked reduction in antibiotic usage following intensive malaria control in a cohort of Ugandan children

BACKGROUND

Intensive malaria control may have additional benefits beyond reducing the incidence of symptomatic malaria. We compared antibiotic treatment of children before and after the implementation of highly effective malaria control interventions in Tororo, a historically high transmission area of Uganda.

METHODS

Two successive cohorts of children, aged 0.5 to 10 years, were followed from September 2011 to October 2019 in a dedicated study clinic. Universal distribution of long-lasting insecticidal nets was conducted in 2013 and 2017. Sustained indoor residual spraying of insecticide (IRS) was initiated in December 2014. Generalized linear mixed-effects models were used to compare the incidence of antimalarial and antibiotic treatments before and after vector control measures were implemented.

RESULTS

Comparing the period prior to the implementation of IRS to the period after IRS had been sustained for 4-5 years, the adjusted incidence of malaria treatments decreased from 2.68 to 0.05 per person-year (incidence rate ratio [IRR] = 0.02, 95% CI 0.01-0.03, p < 0.001), and the adjusted incidence of antibiotic treatments decreased from 4.14 to 1.26 per person-year (IRR = 0.30, 95% CI 0.27-0.34, p < 0.001). The reduction in antibiotic usage was primarily associated with fewer episodes of symptomatic malaria and fewer episodes of fever with sub-microscopic parasitemia, both of which were frequently treated with antibiotics.

CONCLUSIONS

In a historically high transmission setting, the implementation of highly effective vector control interventions was followed by a marked reduction in antibiotic treatment of children. This added benefit of malaria control could have important implications for antibiotic prescribing practices, efforts to curtail antimicrobial resistance, and health system costs.

Qualitative assessment of anti-SARS-CoV-2 spike protein immunogenicity (QUASI) after COVID-19 vaccination in older people living with HIV

Objectives

Effective and safe COVID‐19 vaccines have been developed and have resulted in decreased incidence and severity of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and can decrease secondary transmission. However, there are concerns about dampened immune responses to COVID‐19 vaccination among immunocompromised patients, including people living with HIV (PLWH), which may blunt the vaccine's efficacy and durability of protection. This study aimed to assess the qualitative SARS‐CoV‐2 vaccine immunogenicity among PLWH after vaccination.

Methods

We conducted targeted COVID‐19 vaccination (all received BNT162b2 vaccine) of PLWH (aged ≥ 55 years per state guidelines) at Yale New Haven Health System and established a longitudinal survey to assess their qualitative antibody responses at 3 weeks after the first vaccination (and prior to receipt of the second dose of the COVID‐19 vaccine) (visit 1) and at 2–3 weeks after the second vaccination (visit 2) but excluded patients with prior COVID‐19 infection. Our goal was to assess vaccine‐induced immunity in the population we studied. Qualitative immunogenicity testing was performed using Healgen COVID‐19 anti‐Spike IgG/IgM rapid testing. Poisson regression with robust standard errors was used to determine factors associated with a positive IgG response.

Results

At visit 1, 45 of 78 subjects (57.7%) tested positive for SARS‐CoV‐2 anti‐Spike IgG after the first dose of COVID‐19 vaccine. Thirty‐nine subjects returned for visit 2. Of these, 38 had positive IgG (97.5%), including 20 of 21 subjects (95.2%) with an initial negative anti‐Spike IgG. Our bivariate analysis suggested that participants on an antiretroviral regimen containing integrase strand transfer inhibitors [relative risk (RR) = 1.81, 95% confidence interval (CI): 0.92–3.56, p = 0.085] were more likely to seroconvert after the first dose of the COVID‐19 vaccine, while those with a CD4 count < 500 cells/μL (RR = 0.59, 95% CI: 0.33–1.05, p = 0.071), and those diagnosed with cancer or another immunosuppressive condition (RR = 0.49, 95% CI: 0.18–1.28, p = 0.15) may have been less likely to seroconvert after the first dose of the COVID‐19 vaccine. The direction of these associations was similar in the multivariate model, although none of these findings reached statistical significance (RR_{integrase inhibitor} = 1.71, 95% CI: 0.90–3.25, p = 0.10; RR_{CD4 count} = 0.68, 95% CI: 0.39–1.19, p = 0.18; RR_{cancer or another immunosuppressive condition} = 0.50, 95% CI: 0.19–1.33, p = 0.16). With regard to immunogenicity, we were able to record very high rates of new seroconversion following the second dose of the COVID‐19 vaccine.

Conclusions

Our study suggests that completing a two‐dose series of BNT162b2 vaccine is critical for PLWH given suboptimal seroconversion rates after the first dose and subsequent improved seroconversion rates after the second dose.

Impact of COVID-19 on routine malaria indicators in Uganda: An interrupted time series analysis.. [PMID: 34426808 PMCID: PMC8382131 DOI: 10.21203/rs.3.rs-819495/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background

In March 2020, the government of Uganda implemented a strict lockdown policy in response to the COVID-19 pandemic. We performed an interrupted time series analysis (ITSA) to assess whether major changes in healthcare seeking behavior, malaria burden, and case management occurred after the onset of the COVID-19 epidemic.

Methods

Individual level data from all outpatient visits occurring from April 2017 through March 2021 at 17 facilities were analyzed. Outcomes included total outpatient visits, malaria cases, non-malarial visits, proportion of visits with suspected malaria, proportion of patients tested using rapid diagnostic tests (RDTs), and proportion of malaria cases prescribed artemether-lumefantrine (AL). Pre-COVID trends measured over a three-year period were extrapolated into the post-COVID period (April 2020- March 2021) using Poisson regression with generalized estimating equations or fractional regression. Effects of COVID-19 were estimated over the 12-month post-COVID period by dividing observed values by the predicted values and expressed as ratios.

Results

A total of 1,442,737 outpatient visits were recorded. Malaria was suspected in 55.3% of visits and 98.8% of these had a malaria diagnostic test performed. ITSA showed no differences in the observed versus predicted total outpatient visits, malaria cases, non-malarial visits, or proportion of visits with suspected malaria. However, in the second six months of the post-COVID period, there was a smaller mean proportion of patients tested with RDTs compared to predicted (Relative Prevalence Ratio (RPR) = 0.87, CI [0.78, 0.97]) and a smaller mean proportion of malaria cases prescribed AL (RPR = 0.94, CI [0.90, 0.99].

Conclusions

There was evidence for a modest decrease in the proportion of RDTs used for malaria diagnosis and the proportion of patients prescribed AL in the second half of the post-COVID year, while other malaria indicators remained stable. Continued surveillance will be essential to monitor for changes in trends in malaria indicators so that Uganda can quickly and flexibly respond to challenges imposed by COVID-19.

Persistence of mRNA indicative of Plasmodium falciparum ring-stage parasites 42 days after artemisinin and non-artemisinin combination therapy in naturally infected Malians

Background

Malaria control in sub-Saharan Africa relies upon prompt case management with artemisinin-based combination therapy (ACT). Ring-stage parasite mRNA, measured by sbp1 quantitative reverse-transcriptase PCR (qRT-PCR), was previously reported to persist after ACT treatment and hypothesized to reflect temporary arrest of the growth of ring-stage parasites (dormancy) following exposure to artemisinins. Here, the persistence of ring-stage parasitaemia following ACT and non-ACT treatment was examined.

Methods

Samples were used from naturally infected Malian gametocyte carriers who received dihydroartemisinin–piperaquine (DP) or sulfadoxine–pyrimethamine (SP–AQ) with or without gametocytocidal drugs. Gametocytes and ring-stage parasites were quantified by qRT-PCR during 42 days of follow-up.

Results

At baseline, 89% (64/73) of participants had measurable ring-stage parasite mRNA. Following treatment, the proportion of ring-stage parasite-positive individuals and estimated densities declined for all four treatment groups. Ring-stage parasite prevalence and density was generally lower in arms that received DP compared to SP–AQ. This finding was most apparent days 1, 2, and 42 of follow-up (p < 0.01). Gametocytocidal drugs did not influence ring-stage parasite persistence. Ring-stage parasite density estimates on days 14 and 28 after initiation of treatment were higher among individuals who subsequently experienced recurrent parasitaemia compared to those who remained free of parasites until day 42 after initiation of treatment (p_{day 14} = 0.011 and p_{day 28} = 0.068). No association of ring-stage persistence with gametocyte carriage was observed.

Conclusions

The current findings of lower ring-stage persistence after ACT without an effect of gametocytocidal partner drugs affirms the use of sbp1 as ring-stage marker. Lower persistence of ring-stage mRNA after ACT treatment suggests the marker may not reflect dormant parasites whilst it was predictive of re-appearance of parasitaemia.

Infant sex modifies associations between placental malaria and risk of malaria in infancy

Background

Placental malaria (PM) has been associated with a higher risk of malaria during infancy. However, it is unclear whether this association is causal, and is modified by infant sex, and whether intermittent preventive treatment in pregnancy (IPTp) can reduce infant malaria by preventing PM.

Methods

Data from a birth cohort of 656 infants born to HIV-uninfected mothers randomised to IPTp with dihydroartemisinin–piperaquine (DP) or Sulfadoxine–pyrimethamine (SP) was analysed. PM was categorized as no PM, active PM (presence of parasites), mild-moderate past PM (> 0–20% high powered fields [HPFs] with pigment), or severe past PM (> 20% HPFs with pigment). The association between PM and incidence of malaria in infants stratified by infant sex was examined. Causal mediation analysis was used to test whether IPTp can impact infant malaria incidence via preventing PM.

Results

There were 1088 malaria episodes diagnosed among infants during 596.6 person years of follow-up. Compared to infants born to mothers with no PM, the incidence of malaria was higher among infants born to mothers with active PM (adjusted incidence rate ratio [aIRR] 1.30, 95% CI 1.00–1.71, p = 0.05) and those born to mothers with severe past PM (aIRR 1.28, 95% CI 0.89–1.83, p = 0.18), but the differences were not statistically significant. However, when stratifying by infant sex, compared to no PM, severe past PM was associated a higher malaria incidence in male (aIRR 2.17, 95% CI 1.45–3.25, p < 0.001), but not female infants (aIRR 0.74, 95% CI 0.46–1.20, p = 0.22). There were no significant associations between active PM or mild-moderate past PM and malaria incidence in male or female infants. Male infants born to mothers given IPTp with DP had significantly less malaria in infancy than males born to mothers given SP, and 89.7% of this effect was mediated through prevention of PM.

Conclusion

PM may have more severe consequences for male infants, and interventions which reduce PM could mitigate these sex-specific adverse outcomes. More research is needed to better understand this sex-bias between PM and infant malaria risk.

Trial registration ClinicalTrials.gov, NCT02793622. Registered 8 June 2016, https://clinicaltrials.gov/ct2/show/NCT02793622

Efficacy of Single-Dose Primaquine With Artemisinin Combination Therapy on Plasmodium falciparum Gametocytes and Transmission: An Individual Patient Meta-Analysis

BACKGROUND

Since the World Health Organization recommended single low-dose (0.25 mg/kg) primaquine (PQ) in combination with artemisinin-based combination therapies (ACTs) in areas of low transmission or artemisinin-resistant Plasmodium falciparum, several single-site studies have been conducted to assess efficacy.

METHODS

An individual patient meta-analysis to assess gametocytocidal and transmission-blocking efficacy of PQ in combination with different ACTs was conducted. Random effects logistic regression was used to quantify PQ effect on (1) gametocyte carriage in the first 2 weeks post treatment; and (2) the probability of infecting at least 1 mosquito or of a mosquito becoming infected.

RESULTS

In 2574 participants from 14 studies, PQ reduced PCR-determined gametocyte carriage on days 7 and 14, most apparently in patients presenting with gametocytemia on day 0 (odds ratio [OR], 0.22; 95% confidence interval [CI], .17-.28 and OR, 0.12; 95% CI, .08-.16, respectively). Rate of decline in gametocyte carriage was faster when PQ was combined with artemether-lumefantrine (AL) compared to dihydroartemisinin-piperaquine (DP) (P = .010 for day 7). Addition of 0.25 mg/kg PQ was associated with near complete prevention of transmission to mosquitoes.

CONCLUSIONS

Transmission blocking is achieved with 0.25 mg/kg PQ. Gametocyte persistence and infectivity are lower when PQ is combined with AL compared to DP.

High Genetic Diversity of Plasmodium falciparum in the Low-Transmission Setting of the Kingdom of Eswatini

BACKGROUND

To better understand transmission dynamics, we characterized Plasmodium falciparum genetic diversity in Eswatini, where transmission is low and sustained by importation.

METHODS

Twenty-six P. falciparum microsatellites were genotyped in 66% of confirmed cases (2014-2016; N = 582). Population and within-host diversity were used to characterize differences between imported and locally acquired infections. Logistic regression was used to assess the added value of diversity metrics to classify imported and local infections beyond epidemiology data alone.

RESULTS

Parasite population in Eswatini was highly diverse (expected heterozygosity [HE] = 0.75) and complex: 67% polyclonal infections, mean multiplicity of infection (MOI) 2.2, and mean within-host infection fixation index (FWS) 0.84. Imported cases had comparable diversity to local cases but exhibited higher MOI (2.4 vs 2.0; P = .004) and lower mean FWS (0.82 vs 0.85; P = .03). Addition of MOI and FWS to multivariate analyses did not increase discrimination between imported and local infections.

CONCLUSIONS

In contrast to the common perception that P. falciparum diversity declines with decreasing transmission intensity, Eswatini isolates exhibited high parasite diversity consistent with high rates of malaria importation and limited local transmission. Estimates of malaria transmission intensity from genetic data need to consider the effect of importation, especially as countries near elimination.

Quantification of glucose-6-phosphate dehydrogenase activity by spectrophotometry: A systematic review and meta-analysis

BACKGROUND

The radical cure of Plasmodium vivax and P. ovale requires treatment with primaquine or tafenoquine to clear dormant liver stages. Either drug can induce haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, necessitating screening. The reference diagnostic method for G6PD activity is ultraviolet (UV) spectrophotometry; however, a universal G6PD activity threshold above which these drugs can be safely administered is not yet defined. Our study aimed to quantify assay-based variation in G6PD spectrophotometry and to explore the diagnostic implications of applying a universal threshold.

METHODS AND FINDINGS

Individual-level data were pooled from studies that used G6PD spectrophotometry. Studies were identified via PubMed search (25 April 2018) and unpublished contributions from contacted authors (PROSPERO: CRD42019121414). Studies were excluded if they assessed only individuals with known haematological conditions, were family studies, or had insufficient details. Studies of malaria patients were included but analysed separately. Included studies were assessed for risk of bias using an adapted form of the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Repeatability and intra- and interlaboratory variability in G6PD activity measurements were compared between studies and pooled across the dataset. A universal threshold for G6PD deficiency was derived, and its diagnostic performance was compared to site-specific thresholds. Study participants (n = 15,811) were aged between 0 and 86 years, and 44.4% (7,083) were women. Median (range) activity of G6PD normal (G6PDn) control samples was 10.0 U/g Hb (6.3-14.0) for the Trinity assay and 8.3 U/g Hb (6.8-15.6) for the Randox assay. G6PD activity distributions varied significantly between studies. For the 13 studies that used the Trinity assay, the adjusted male median (AMM; a standardised metric of 100% G6PD activity) varied from 5.7 to 12.6 U/g Hb (p < 0.001). Assay precision varied between laboratories, as assessed by variance in control measurements (from 0.1 to 1.5 U/g Hb; p < 0.001) and study-wise mean coefficient of variation (CV) of replicate measures (from 1.6% to 14.9%; p < 0.001). A universal threshold of 100% G6PD activity was defined as 9.4 U/g Hb, yielding diagnostic thresholds of 6.6 U/g Hb (70% activity) and 2.8 U/g Hb (30% activity). These thresholds diagnosed individuals with less than 30% G6PD activity with study-wise sensitivity from 89% (95% CI: 81%-94%) to 100% (95% CI: 96%-100%) and specificity from 96% (95% CI: 89%-99%) to 100% (100%-100%). However, when considering intermediate deficiency (<70% G6PD activity), sensitivity fell to a minimum of 64% (95% CI: 52%-75%) and specificity to 35% (95% CI: 24%-46%). Our ability to identify underlying factors associated with study-level heterogeneity was limited by the lack of availability of covariate data and diverse study contexts and methodologies.

CONCLUSIONS

Our findings indicate that there is substantial variation in G6PD measurements by spectrophotometry between sites. This is likely due to variability in laboratory methods, with possible contribution of unmeasured population factors. While an assay-specific, universal quantitative threshold offers robust diagnosis at the 30% level, inter-study variability impedes performance of universal thresholds at the 70% level. Caution is advised in comparing findings based on absolute G6PD activity measurements across studies. Novel handheld quantitative G6PD diagnostics may allow greater standardisation in the future.

Safety of Single-Dose Primaquine in G6PD-Deficient and G6PD-Normal Males in Mali Without Malaria: An Open-Label, Phase 1, Dose-Adjustment Trial

Background

The World Health Organization recommendation on the use of a single low dose of primaquine (SLD-PQ) to reduce Plasmodium falciparum malaria transmission requires more safety data.

Methods

We conducted an open-label, nonrandomized, dose-adjustment trial of the safety of 3 single doses of primaquine in glucose-6-phosphate dehydrogenase (G6PD)-deficient adult males in Mali, followed by an assessment of safety in G6PD-deficient boys aged 11–17 years and those aged 5–10 years, including G6PD-normal control groups. The primary outcome was the greatest within-person percentage drop in hemoglobin concentration within 10 days after treatment.

Results

Fifty-one participants were included in analysis. G6PD-deficient adult males received 0.40, 0.45, or 0.50 mg/kg of SLD-PQ. G6PD-deficient boys received 0.40 mg/kg of SLD-PQ. There was no evidence of symptomatic hemolysis, and adverse events considered related to study drug (n = 4) were mild. The mean largest within-person percentage change in hemoglobin level between days 0 and 10 was −9.7% (95% confidence interval [CI], −13.5% to −5.90%) in G6PD-deficient adults receiving 0.50 mg/kg of SLD-PQ, −11.5% (95% CI, −16.1% to −6.96%) in G6PD-deficient boys aged 11–17 years, and −9.61% (95% CI, −7.59% to −13.9%) in G6PD-deficient boys aged 5–10 years. The lowest hemoglobin concentration at any point during the study was 92 g/L.

Conclusion

SLD-PQ doses between 0.40 and 0.50 mg/kg were well tolerated in G6PD-deficient males in Mali.

Clinical Trials Registration

NCT02535767.

Protective Effect of Indoor Residual Spraying of Insecticide on Preterm Birth Among Pregnant Women With HIV Infection in Uganda: A Secondary Data Analysis

Background

Recent evidence demonstrated improved birth outcomes among human immunodeficiency virus (HIV)-uninfected pregnant women protected by indoor residual spraying of insecticide (IRS). Evidence regarding its impact on HIV-infected pregnant women is lacking.

Methods

Data were pooled from 2 studies conducted before and after an IRS campaign in Tororo, Uganda, among HIV-infected pregnant women who received bed nets, daily trimethoprim-sulfamethoxazole, and combination antiretroviral therapy at enrollment. Exposure was the proportion of pregnancy protected by IRS. Adverse birth outcomes included preterm birth, low birth weight, and fetal or neonatal death. Multivariate Poisson regression with robust standard errors was used to estimate risk ratios.

Results

Of 565 women in our analysis, 380 (67%), 88 (16%), and 97 (17%) women were protected by IRS for 0%, >0% to 90%, and >90% of their pregnancy, respectively. Any IRS protection significantly reduced malaria incidence during pregnancy and placental malaria risk. Compared with no IRS protection, >90% IRS protection reduced preterm birth risk (risk ratio, 0.35; 95% confidence interval, .15-.84), with nonsignificant decreases in the risk of low birth weight (0.68; .29-1.57) and fetal or neonatal death (0.24; .04-1.52).

Discussion

Our exploratory analyses support the hypothesis that IRS may significantly reduce malaria and preterm birth risk among pregnant women with HIV receiving bed nets, daily trimethoprim-sulfamethoxazole, and combination antiretroviral therapy.

Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial

BACKGROUND

Primaquine and methylene blue are gametocytocidal compounds that could prevent Plasmodium falciparum transmission to mosquitoes. We aimed to assess the efficacy and safety of primaquine and methylene blue in preventing human to mosquito transmission of P falciparum among glucose-6-phosphate dehydrogenase (G6PD)-normal, gametocytaemic male participants.

METHODS

This was a phase 2, single-blind, randomised controlled trial done at the Clinical Research Centre of the Malaria Research and Training Centre (MRTC) of the University of Bamako (Bamako, Mali). We enrolled male participants aged 5-50 years with asymptomatic P falciparum malaria. G6PD-normal participants with gametocytes detected by blood smear were randomised 1:1:1:1 in block sizes of eight, using a sealed-envelope design, to receive either sulfadoxine-pyrimethamine and amodiaquine, sulfadoxine-pyrimethamine and amodiaquine plus a single dose of 0·25 mg/kg primaquine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus 15 mg/kg per day methylene blue for 3 days. Laboratory staff, investigators, and insectary technicians were masked to the treatment group and gametocyte density of study participants. The study pharmacist and treating physician were not masked. Participants could request unmasking. The primary efficacy endpoint, analysed in all infected patients with at least one infectivity measure before and after treatment, was median within-person percentage change in mosquito infectivity 2 and 7 days after treatment, assessed by membrane feeding. This study is registered with ClinicalTrials.gov, number NCT02831023.

FINDINGS

Between June 27, 2016, and Nov 1, 2016, 80 participants were enrolled and assigned to the sulfadoxine-pyrimethamine and amodiaquine (n=20), sulfadoxine-pyrimethamine and amodiaquine plus primaquine (n=20), dihydroartemisinin-piperaquine (n=20), or dihydroartemisinin-piperaquine plus methylene blue (n=20) groups. Among participants infectious at baseline (54 [68%] of 80), those in the sulfadoxine-pyrimethamine and amodiaquine plus primaquine group (n=19) had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with sulfadoxine-pyrimethamine and amodiaquine alone (n=12; -10·2%, IQR -143·9 to 56·6; p<0·0001). The dihydroartemisinin-piperaquine plus methylene blue (n=11) group had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with dihydroartemisinin-piperaquine alone (n=12; -6·0%, IQR -126·1 to 86·9; p<0·0001). Haemoglobin changes were similar between gametocytocidal arms and their respective controls. After exclusion of blue urine, adverse events were similar across all groups (59 [74%] of 80 participants had 162 adverse events overall, 145 [90%] of which were mild).

INTERPRETATION

Adding a single dose of 0·25 mg/kg primaquine to sulfadoxine-pyrimethamine and amodiaquine or 3 days of 15 mg/kg per day methylene blue to dihydroartemisinin-piperaquine was highly efficacious for preventing P falciparum transmission. Both primaquine and methylene blue were well tolerated.

FUNDING

Bill & Melinda Gates Foundation, European Research Council.

Asymptomatic Plasmodium Infections in Children in Low Malaria Transmission Setting, Southwestern Uganda(1)

A survey of asymptomatic children in Uganda showed Plasmodium malariae and P. falciparum parasites in 45% and 55% of microscopy-positive samples, respectively. Although 36% of microscopy-positive samples were negative by rapid diagnostic test, 75% showed P. malariae or P. ovale parasites by PCR, indicating that routine diagnostic testing misses many non-P. falciparum malarial infections.

Evaluation of the Deki Reader™, an automated RDT reader and data management device, in a household survey setting in low malaria endemic southwestern Uganda

Background

Early diagnosis of suspected malaria cases with a rapid diagnostic test (RDT) has been shown to be an effective malaria control tool used in many resource-constrained settings. However, poor quality control and quality assurance hinder the accurate reporting of malaria diagnoses. Recent use of a portable, battery operated RDT reader (Deki Reader™, Fio Corporation) has shown to have high agreement with visual inspection across diverse health centre settings, however evidence of its feasibility and usability during cross sectional surveys are limited. This study aimed to evaluate the performance of the Deki Reader™ in a cross-sectional survey of children from southwestern Uganda.

Methods

A two-stage, stratified cluster sampling survey was conducted between July and October 2014 in three districts of southwestern Uganda, with varying malaria transmission intensities. A total of 566 children aged 6–59 months were included in the analysis. Blood samples were collected and tested for malaria using: the SD Bioline Malaria Ag Pf/Pan RDT and microscopy. Results were compared between visual inspection of the RDT and by the Deki Reader™. Diagnostic performance of both methods were compared to gold-standard microscopy.

Results

The sensitivity and specificity of the Deki Reader™ was 94.1% (95% CI 69.2–99.6%) and 95.6% (95% CI 93.4–97.1%), respectively. The overall percent agreement between the Deki Reader™ and visual RDT inspection was 98.9% (95% CI 93.2–99.8), with kappa statistic of 0.92 (95% CI 0.85–0.98).

Conclusions

The findings from this study suggest that the Deki Reader™ is comparable to visual inspection and performs well in detecting microscopy-positive Plasmodium falciparum cases in a household survey setting. However, the reader’s performance was highly dependent on ensuring adequate battery life and a work environment free of dirt particles.

Screening for Glucose-6-Phosphate Dehydrogenase Deficiency Using Three Detection Methods: A Cross-Sectional Survey in Southwestern Uganda

Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech^® G-6-PDH kit), a qualitative point-of-care test (CareStart^™ G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A- G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart^™ G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region.