Short-term malaria reduction by single-dose azithromycin during mass drug administration for trachoma, Tanzania

Targeting malaria parasites with novel derivatives of azithromycin

Introduction

The spread of artemisinin resistant Plasmodium falciparum parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a macrolide antibiotic used clinically against malaria, kills parasites via two mechanisms: 'delayed death' by inhibiting the bacterium-like ribosomes of the apicoplast, and 'quick-killing' that kills rapidly across the entire blood stage development.

Methods

Here, 22 azithromycin analogues were explored for delayed death and quick-killing activities against P. falciparum (the most virulent human malaria) and P. knowlesi (a monkey parasite that frequently infects humans).

Results

Seventeen analogues showed improved quick-killing against both Plasmodium species, with up to 38 to 20-fold higher potency over azithromycin after less than 48 or 28 hours of treatment for P. falciparum and P. knowlesi, respectively. Quick-killing analogues maintained activity throughout the blood stage lifecycle, including ring stages of P. falciparum parasites (<12 hrs treatment) and were >5-fold more selective against P. falciparum than human cells. Isopentenyl pyrophosphate supplemented parasites that lacked an apicoplast were equally sensitive to quick-killing analogues, confirming that the quick killing activity of these drugs was not directed at the apicoplast. Further, activity against the related apicoplast containing parasite Toxoplasma gondii and the gram-positive bacterium Streptococcus pneumoniae did not show improvement over azithromycin, highlighting the specific improvement in antimalarial quick-killing activity. Metabolomic profiling of parasites subjected to the most potent compound showed a build-up of non-haemoglobin derived peptides that was similar to chloroquine, while also exhibiting accumulation of haemoglobin-derived peptides that was absent for chloroquine treatment.

Discussion

The azithromycin analogues characterised in this study expand the structural diversity over previously reported quick-killing compounds and provide new starting points to develop azithromycin analogues with quick-killing antimalarial activity.

Secondary Effects from Mass Azithromycin Administration: A Systematic Review and Meta-analysis

The effects of azithromycin mass drug administration (MDA) on trachoma and yaws have been addressed. However, the secondary effects of azithromycin MDA remain unclear. This study aimed to explore the secondary effects of azithromycin MDA. PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov were searched from conception to January 5, 2022. Studies on secondary effects of azithromycin MDA were included. A total of 34 studies were included. Six of them reported on child mortality, 10 on malaria, and 20 on general morbidity and condition. Azithromycin MDA reduced child mortality, and quarterly MDA may be most beneficial for reducing child mortality. The effect of azithromycin MDA on malaria was weak. No association was observed between azithromycin MDA and malaria parasitemia (rate ratio: 0.71, 95% confidence interval: 0.43-1.15). Azithromycin MDA was associated with a lower risk of respiratory tract infections and diarrhea. Additionally, it was associated with a lower risk of fever, vomiting, and headache. The carriage of pathogenic organisms such as Streptococcus pneumoniae and gut Campylobacter species was reduced. However, these secondary effects of azithromycin MDA appeared to last only a few weeks. Moreover, no association was observed between azithromycin MDA and nutritional improvement in children. In conclusion, azithromycin MDA had favorable secondary effects on child mortality and morbidity. However, the effects were short term.

Mass drug administration of antibacterials: weighing the evidence regarding benefits and risks

Background

Mass drug administration (MDA) is a strategy to improve health at the population level through widespread delivery of medicine in a community. We surveyed the literature to summarize the benefits and potential risks associated with MDA of antibacterials, focusing predominantly on azithromycin as it has the greatest evidence base.

Main body

High-quality evidence from randomized controlled trials (RCTs) indicate that MDA-azithromycin is effective in reducing the prevalence of infection due to yaws and trachoma. In addition, RCTs suggest that MDA-azithromycin reduces under-five mortality in certain low-resource settings that have high childhood mortality rates at baseline. This reduction in mortality appears to be sustained over time with twice-yearly MDA-azithromycin, with the greatest effect observed in children < 1 year of age. In addition, observational data suggest that infections such as skin and soft tissue infections, rheumatic heart disease, acute respiratory illness, diarrheal illness, and malaria may all be treated by azithromycin and thus incidentally impacted by MDA-azithromycin. However, the mechanism by which MDA-azithromycin reduces childhood mortality remains unclear. Verbal autopsies performed in MDA-azithromycin childhood mortality studies have produced conflicting data and are underpowered to answer this question. In addition to benefits, there are several important risks associated with MDA-azithromycin. Direct adverse effects potentially resulting from MDA-azithromycin include gastrointestinal side effects, idiopathic hypertrophic pyloric stenosis, cardiovascular side effects, and increase in chronic diseases such as asthma and obesity. Antibacterial resistance is also a risk associated with MDA-azithromycin and has been reported for both gram-positive and enteric organisms. Further, there is the risk for cross-resistance with other antibacterial agents, especially clindamycin.

Conclusions

Evidence shows that MDA-azithromycin programs may be beneficial for reducing trachoma, yaws, and mortality in children < 5 years of age in certain under-resourced settings. However, there are significant potential risks that need to be considered when deciding how, when, and where to implement these programs. Robust systems to monitor benefits as well as adverse effects and antibacterial resistance are warranted in communities where MDA-azithromycin programs are implemented.

Graphical Abstract

Trachoma

Trachoma is a neglected tropical disease caused by infection with conjunctival strains of Chlamydia trachomatis. It can result in blindness. Pathophysiologically, trachoma is a disease complex composed of two linked chronic processes: a recurrent, generally subclinical infectious-inflammatory disease that mostly affects children, and a non-communicable, cicatricial and, owing to trichiasis, eventually blinding disease that supervenes in some individuals later in life. At least 150 infection episodes over an individual's lifetime are needed to precipitate trichiasis; thus, opportunity exists for a just global health system to intervene to prevent trachomatous blindness. Trachoma is found at highest prevalence in the poorest communities of low-income countries, particularly in sub-Saharan Africa; in June 2021, 1.8 million people worldwide were going blind from the disease. Blindness attributable to trachoma can appear in communities many years after conjunctival C. trachomatis transmission has waned or ceased; therefore, the two linked disease processes require distinct clinical and public health responses. Surgery is offered to individuals with trichiasis and antibiotic mass drug administration and interventions to stimulate facial cleanliness and environmental improvement are designed to reduce infection prevalence and transmission. Together, these interventions comprise the SAFE strategy, which is achieving considerable success. Although much work remains, a continuing public health problem from trachoma in the year 2030 will be difficult for the world to excuse.

Malaria positivity following a single oral dose of azithromycin among children in Burkina Faso: a randomized controlled trial

Background

Azithromycin is a broad-spectrum antibiotic that has moderate antimalarial activity and has been shown to reduce all-cause mortality when biannually administered to children under five in high mortality settings in sub-Saharan Africa. One potential mechanism for this observed reduction in mortality is via a reduction in malaria transmission.

Methods

We evaluated whether a single oral dose of azithromycin reduces malaria positivity by rapid diagnostic test (RDT). We conducted an individually randomized placebo-controlled trial in Burkina Faso during the high malaria transmission season in August 2020. Children aged 8 days to 59 months old were randomized to a single oral dose of azithromycin (20 mg/kg) or matching placebo. At baseline and 14 days following treatment, we administered a rapid diagnostic test (RDT) to detect Plasmodium falciparum and measured tympanic temperature for all children. Caregiver-reported adverse events and clinic visits were recorded at the day 14 visit.

Results

We enrolled 449 children with 221 randomized to azithromycin and 228 to placebo. The median age was 32 months and 48% were female. A total of 8% of children had a positive RDT for malaria at baseline and 11% had a fever (tympanic temperature ≥ 37.5 °C). In the azithromycin arm, 8% of children had a positive RDT for malaria at 14 days compared to 7% in the placebo arm (P = 0.65). Fifteen percent of children in the azithromycin arm had a fever ≥ 37.5 °C compared to 21% in the placebo arm (P = 0.12). Caregivers of children in the azithromycin group had lower odds of reporting fever as an adverse event compared to children in the placebo group (OR 0.41, 95% CI 0.18–0.96, P = 0.04). Caregiver-reported clinic visits were uncommon, and there were no observed differences between arms (P = 0.32).

Conclusions

We did not find evidence that a single oral dose of azithromycin reduced malaria positivity during the high transmission season. Caregiver-reported fever occurred less often in children receiving azithromycin compared to placebo, indicating that azithromycin may have some effect on non-malarial infections.

Trial registration Clinicaltrials.gov NCT04315272, registered 19/03/2020

MolData, a molecular benchmark for disease and target based machine learning

Deep learning’s automatic feature extraction has been a revolutionary addition to computational drug discovery, infusing both the capabilities of learning abstract features and discovering complex molecular patterns via learning from molecular data. Since biological and chemical knowledge are necessary for overcoming the challenges of data curation, balancing, training, and evaluation, it is important for databases to contain information regarding the exact target and disease of each bioassay. The existing depositories such as PubChem or ChEMBL offer the screening data for millions of molecules against a variety of cells and targets, however, their bioassays contain complex biological descriptions which can hinder their usage by the machine learning community. In this work, a comprehensive disease and target-based dataset is collected from PubChem in order to facilitate and accelerate molecular machine learning for better drug discovery. MolData is one the largest efforts to date for democratizing the molecular machine learning, with roughly 170 million drug screening results from 1.4 million unique molecules assigned to specific diseases and targets. It also provides 30 unique categories of targets and diseases. Correlation analysis of the MolData bioassays unveils valuable information for drug repurposing for multiple diseases including cancer, metabolic disorders, and infectious diseases. Finally, we provide a benchmark of more than 30 models trained on each category using multitask learning. MolData aims to pave the way for computational drug discovery and accelerate the advancement of molecular artificial intelligence in a practical manner. The MolData benchmark data is available at https://GitHub.com/Transilico/MolData as well as within the additional files.

Impact of azithromycin mass drug administration on the antibiotic-resistant gut microbiome in children: a randomized, controlled trial

BACKGROUND

Mass drug administration (MDA) with azithromycin is the primary strategy for global trachoma control efforts. Numerous studies have reported secondary effects of MDA with azithromycin, including reductions in childhood mortality, diarrhoeal disease and malaria. Most recently, the MORDOR clinical trial demonstrated that MDA led to an overall reduction in all-cause childhood mortality in targeted communities. There is however concern about the potential of increased antimicrobial resistance in treated communities. This study evaluated the impact of azithromycin MDA on the prevalence of gastrointestinal carriage of macrolide-resistant bacteria in communities within the MORDOR Malawi study, additionally profiling changes in the gut microbiome after treatment. For faecal metagenomics, 60 children were sampled prior to treatment and 122 children after four rounds of MDA, half receiving azithromycin and half placebo.

RESULTS

The proportion of bacteria carrying macrolide resistance increased after azithromycin treatment. Diversity and global community structure of the gut was minimally impacted by treatment, however abundance of several species was altered by treatment. Notably, the putative human enteropathogen Escherichia albertii was more abundant after treatment.

CONCLUSIONS

MDA with azithromycin increased carriage of macrolide-resistant bacteria, but had limited impact on clinically relevant bacteria. However, increased abundance of enteropathogenic Escherichia species after treatment requires further, higher resolution investigation. Future studies should focus on the number of treatments and administration schedule to ensure clinical benefits continue to outweigh costs in antimicrobial resistance carriage. Trial registration ClinicalTrial.gov, NCT02047981. Registered January 29th 2014, https://clinicaltrials.gov/ct2/show/NCT02047981.

Morbidity in a Longitudinal Cohort of Children Residing in Villages Randomized to Biannual Treatment With Azithromycin Versus Placebo

BACKGROUND

The mechanisms underlying the finding of reduced child mortality in communities with biannual treatment with azithromycin remain unclear. We determined if there was a difference in morbidity in a cohort of children aged 1-36 months, residing in communities randomized to biannual treatment of preschool-aged children with azithromycin or placebo.

METHODS

Thirty villages in Kilosa, Tanzania, were randomly assigned to receive biannual treatment of all children aged 1-59 months with either azithromycin (20/mg/kg single dose) or placebo. Children who were aged 1-36 months and participated in the baseline survey were enrolled in this cohort study and followed prospectively for 2 years. Children were monitored every 6 months for signs and symptoms of diarrheal disease, acute respiratory illness, and anemia. Mixed-effects models that include age, time, treatment arm, and the interaction of treatment arm and time as independent predictors were used to evaluate differences between children by treatment assignment over time.

RESULTS

There was no difference in rates of diarrhea, fever, or anemia by treatment arm at baseline and at all phases of follow-up. The decline over time in reported cough was statistically significant in the children residing in the azithromycin communities, but not in the placebo communities. Once adjusting for clustering and age, the difference in decline between the 2 treatment arms was not significant (P = .09).

CONCLUSIONS

A beneficial effect of azithromycin treatment on morbidity outcomes was not evident at biannual surveys.

CLINICAL TRIALS REGISTRATION

NCT02048007.

Malaria Parasitemia and Nutritional Status during the Low Transmission Season in the Presence of Azithromycin Distribution among Preschool Children in Niger

The relationship between malaria and malnutrition is complicated, and existence of one may predispose or exacerbate the other. We evaluated the relationship between malaria parasitemia and nutritional status in children living in communities participating in a cluster-randomized trial of biannual azithromycin compared with placebo for prevention of childhood mortality. Data were collected during the low malaria transmission and low food insecurity season. Parasitemia was not associated with weight-for-height Z-score (24 months: P = 0.11 azithromycin communities, P = 0.75 placebo communities), weight-for-age Z-score (24 months: P = 0.83 azithromycin, P = 0.78 placebo), height-for-age Z-score (24 months: P = 0.30 azithromycin, P = 0.87 placebo), or mid-upper arm circumference (24 months: P = 0.12 azithromycin, P = 0.56 placebo). There was no statistically significant evidence of a difference in the relationship in communities receiving azithromycin or placebo. During the low transmission season, there was no evidence that malaria parasitemia and impaired nutritional status co-occur in children.

Effect of Mass Treatment with Azithromycin on Causes of Death in Children in Malawi: Secondary Analysis from the MORDOR Trial

Recent evidence indicates mass drug administration with azithromycin may reduce child mortality. This study uses verbal autopsy (VA) to investigate the causes of individual deaths during the Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial in Malawi. Cluster randomization was performed as part of MORDOR. Biannual household visits were conducted to distribute azithromycin or placebo to children aged 1–59 months and update the census to identify deaths for VA. MORDOR was not powered to investigate mortality effects at individual sites, but the available evidence is presented here for hypothesis generation regarding the mechanism through which azithromycin may reduce child mortality. Automated VA analysis was performed to infer the likely cause of death using two major analysis programs, InterVA and SmartVA. A total of 334 communities were randomized to azithromycin or placebo, with more than 130,000 person-years of follow-up. During the study, there were 1,184 deaths, of which 1,131 were followed up with VA. Mortality was 9% lower in azithromycin-treated communities than in placebo communities (rate ratio 0.91 [95% CI: 0.79–1.05]; P = 0.20). The intention-to-treat analysis by cause using InterVA suggested fewer HIV/AIDS deaths in azithromycin-treated communities (rate ratio 0.70 [95% CI: 0.50–0.97]; P = 0.03) and fewer pneumonia deaths (rate ratio 0.82 [95% CI: 0.60–1.12]; P = 0.22). The use of the SmartVA algorithm suggested fewer diarrhea deaths (rate ratio 0.71 [95% CI: 0.51–1.00]; P = 0.05) and fewer pneumonia deaths (rate ratio 0.58 [95% CI: 0.33–1.00]; P = 0.05). Although this study is not able to provide strong evidence, the data suggest that the mortality reduction during MORDOR in Malawi may have been due to effects on pneumonia and diarrhea or HIV/AIDS mortality.

Genomics of Ocular Chlamydia trachomatis after 5 years of SAFE interventions for trachoma in Amhara, Ethiopia

To eliminate trachoma as a public health problem, the WHO recommends the SAFE (Surgery, Antibiotics, Facial cleanliness, and Environmental improvement) strategy. As part of the SAFE strategy in the Amhara Region, Ethiopia, the Trachoma Control Program distributed over 124 million doses of antibiotic between 2007 and 2015. Despite this, trachoma remained hyperendemic in many districts and a considerable level of Chlamydia trachomatis (Ct) infection was evident. We utilised residual material from Abbott m2000 Ct diagnostic tests to sequence 99 ocular Ct samples from Amhara and investigated the role of Ct genomic variation in continued transmission of Ct. Sequences were typical of ocular Ct, at the whole-genome level and in tissue tropism-associated genes. There was no evidence of macrolide-resistance in this population. Polymorphism around ompA gene was associated with village-level trachomatous inflammation-follicular prevalence. Greater ompA diversity at the district-level was associated with increased Ct infection prevalence. We found no evidence for Ct genomic variation contributing to continued transmission of Ct after treatment, adding to evidence that azithromycin does not drive acquisition of macrolide resistance in Ct. Increased Ct infection in areas with more ompA variants requires longitudinal investigation to understand what impact this may have on treatment success and host immunity.

Retargeting azithromycin analogues to have dual-modality antimalarial activity

BACKGROUND

Resistance to front-line antimalarials (artemisinin combination therapies) is spreading, and development of new drug treatment strategies to rapidly kill Plasmodium spp. malaria parasites is urgently needed. Azithromycin is a clinically used macrolide antibiotic proposed as a partner drug for combination therapy in malaria, which has also been tested as monotherapy. However, its slow-killing 'delayed-death' activity against the parasite's apicoplast organelle and suboptimal activity as monotherapy limit its application as a potential malaria treatment. Here, we explore a panel of azithromycin analogues and demonstrate that chemical modifications can be used to greatly improve the speed and potency of antimalarial action.

RESULTS

Investigation of 84 azithromycin analogues revealed nanomolar quick-killing potency directed against the very earliest stage of parasite development within red blood cells. Indeed, the best analogue exhibited 1600-fold higher potency than azithromycin with less than 48 hrs treatment in vitro. Analogues were effective against zoonotic Plasmodium knowlesi malaria parasites and against both multi-drug and artemisinin-resistant Plasmodium falciparum lines. Metabolomic profiles of azithromycin analogue-treated parasites suggested activity in the parasite food vacuole and mitochondria were disrupted. Moreover, unlike the food vacuole-targeting drug chloroquine, azithromycin and analogues were active across blood-stage development, including merozoite invasion, suggesting that these macrolides have a multi-factorial mechanism of quick-killing activity. The positioning of functional groups added to azithromycin and its quick-killing analogues altered their activity against bacterial-like ribosomes but had minimal change on 'quick-killing' activity. Apicoplast minus parasites remained susceptible to both azithromycin and its analogues, further demonstrating that quick-killing is independent of apicoplast-targeting, delayed-death activity.

CONCLUSION

We show that azithromycin and analogues can rapidly kill malaria parasite asexual blood stages via a fast action mechanism. Development of azithromycin and analogues as antimalarials offers the possibility of targeting parasites through both a quick-killing and delayed-death mechanism of action in a single, multifactorial chemotype.

Mass Oral Azithromycin for Childhood Mortality: Timing of Death After Distribution in the MORDOR Trial

In a large community-randomized trial, biannual azithromycin distributions significantly reduced postneonatal childhood mortality in sub-Saharan African sites. Here, we present a prespecified secondary analysis showing that much of the protective effect was in the first 3 months postdistribution. Distributing more frequently than biannually could be considered if logistically feasible.

Clinical Trials Registration. NCT02047981.

Repurposing Drugs to Fight Hepatic Malaria Parasites

Malaria remains one of the most prevalent infectious diseases worldwide, primarily affecting some of the most vulnerable populations around the globe. Despite achievements in the treatment of this devastating disease, there is still an urgent need for the discovery of new drugs that tackle infection by Plasmodium parasites. However, de novo drug development is a costly and time-consuming process. An alternative strategy is to evaluate the anti-plasmodial activity of compounds that are already approved for other purposes, an approach known as drug repurposing. Here, we will review efforts to assess the anti-plasmodial activity of existing drugs, with an emphasis on the obligatory and clinically silent liver stage of infection. We will also review the current knowledge on the classes of compounds that might be therapeutically relevant against Plasmodium in the context of other communicable diseases that are prevalent in regions where malaria is endemic. Repositioning existing compounds may constitute a faster solution to the current gap of prophylactic and therapeutic drugs that act on Plasmodium parasites, overall contributing to the global effort of malaria eradication.

Effects of Biannual Azithromycin Mass Drug Administration on Malaria in Malawian Children: A Cluster-Randomized Trial

Reductions in malaria morbidity have been reported following azithromycin mass drug administration (MDA) for trachoma. The recent Macrolides Oraux pour Reduire les Deces avec un Oeil sur la Resistance (MORDOR) trial reported a reduction in child mortality following biannual azithromycin MDA. Here, we investigate the effects of azithromycin MDA on malaria at the MORDOR-Malawi study site. A cluster-randomized double-blind placebo-controlled trial, with 15 clusters per arm, was conducted. House-to-house census was updated biannually, and azithromycin or placebo syrup was distributed to children aged 1–59 months for a total of four biannual distributions. At baseline, 12-month, and 24-month follow-up visits, a random sample of 1,200 children was assessed for malaria with thick and thin blood smears and hemoglobin measurement. In the community-level analysis, there was no difference in the prevalence of parasitemia (1.0% lower in azithromycin-treated communities; 95% CI: −8.2 to 6.1), gametocytemia (0.7% lower in azithromycin-treated communities; 95% CI: −2.8 to 1.5), or anemia (1.7% lower in azithromycin-treated communities; 95% CI: −8.1 to 4.6) between placebo and azithromycin communities. Further interrogation of the data at the individual level, both per-protocol (including only those who received treatment 6 months previously) and by intention-to-treat, did not identify differences in parasitemia between treatment arms. In contrast to several previous reports, this study did not show an effect of azithromycin MDA on malaria parasitemia at the community or individual levels.

Cost-Effectiveness of Mass Treatment with Azithromycin for Reducing Child Mortality in Malawi: Secondary Analysis from the MORDOR Trial

The recent Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial reported a reduction in child mortality following biannual azithromycin mass drug administration (MDA). Here, we investigate the financial costs and cost-effectiveness from the health provider perspective of azithromycin MDA at the MORDOR-Malawi study site. During MORDOR, a cluster-randomized trial involving biannual azithromycin MDA or placebo to children aged 1–59 months, fieldwork-related costs were collected, including personnel, transport, consumables, overheads, training, and supervision. Mortality rates in azithromycin- and placebo-treated clusters were calculated overall and for the five health zones of Mangochi district. These were used to estimate the number needed to treat to avert one death and the costs per death and disability-adjusted life year (DALY) averted. The cost per dose of MDA was $0.74 overall, varying between $0.63 and $0.94 in the five zones. Overall, the number needed to treat to avert one death was 1,213 children; the cost per death averted was $898.47, and the cost per DALY averted was $9.98. In the three zones where mortality was lower in azithromycin-treated clusters, the number needed to treat to avert one death, cost per death averted, and cost per DALY averted, respectively, were as follows: 3,070, $2,899.24, and $32.31 in Monkey Bay zone; 1,530, $1,214.42, and $13.49 in Chilipa zone; and 344, $217.98, and $2.42 in Namwera zone. This study is a preliminary cost-effectiveness analysis that indicates azithromycin MDA for reducing child mortality has the potential to be highly cost-effective in some settings in Malawi, but the reasons for geographical variation in effectiveness require further investigation.

Mass Azithromycin Distribution to Prevent Childhood Mortality: A Pooled Analysis of Cluster-Randomized Trials

Mass drug administration (MDA) with azithromycin may reduce under-5 child mortality (U5M) in sub-Saharan Africa. Here, we conducted a pooled analysis of all published cluster-randomized trials evaluating the effect of azithromycin MDA on child mortality. We pooled data from cluster-randomized trials randomizing communities to azithromycin MDA versus control. We calculated mortality rates in the azithromycin and control arms in each study, and by country for multisite studies including multiple countries. We conducted a two-stage individual community data meta-analysis to estimate the effect of azithromycin for prevention of child mortality. Three randomized controlled trials in four countries (Ethiopia, Malawi, Niger, and Tanzania) were identified. The overall pooled mortality rate was 15.9 per 1,000 person-years (95% confidence interval [CI]: 15.5–16.3). The pooled mortality rate was lower in azithromycin-treated communities than in placebo-treated communities (14.7 deaths per 1,000 person-years, 95% CI: 14.2–15.3 versus 17.2 deaths per 1,000 person-years, 95% CI: 16.5–17.8). There was a 14.4% reduction in all-cause child mortality in communities receiving azithromycin MDA (95% CI: 6.3–21.7% reduction, P = 0.0007). All-cause U5M was lower in communities receiving azithromycin MDA than in control communities, suggesting that azithromycin MDA could be a new tool to reduce child mortality in sub-Saharan Africa. However, heterogeneity in effect estimates suggests that the magnitude of the effect may vary in time and space and is currently not predictable.

Biannual versus annual mass azithromycin distribution and malaria seroepidemiology among preschool children in Niger: a sub-study of a cluster randomized trial

Background

Biannual mass azithromycin administration to preschool children reduces all-cause mortality, but the mechanism for the effect is not understood. Azithromycin has activity against malaria parasites, and malaria is a leading cause of child mortality in the Sahel. The effect of biannual versus annual azithromycin distribution for trachoma control on serological response to merozoite surface protein 1 (MSP-1₁₉), a surrogate for malaria incidence, was evaluated among children in Niger.

Methods

Markers of malaria exposure were measured in two arms of a factorial randomized controlled trial designed to evaluate targeted biannual azithromycin distribution to children under 12 years of age compared to annual azithromycin to the entire community for trachoma control (N = 12 communities per arm). Communities were treated for 36 months (6 versus 3 distributions). Dried blood spots were collected at 36 months among children ages 1–5 years, and MSP-1₁₉ antibody levels were assessed using a bead-based multiplex assay to measure malaria seroprevalence.

Results

Antibody results were available for 991 children. MSP-1₁₉ seropositivity was 62.7% in the biannual distribution arm compared to 68.7% in the annual arm (prevalence ratio 0.91, 95% CI 0.83 to 1.00). Mean semi-quantitative antibody levels were lower in the biannual distribution arm compared to the annual arm (mean difference − 0.39, 95% CI − 0.05 to − 0.72).

Conclusions

Targeted biannual azithromycin distribution was associated with lower malaria seroprevalence compared to that in a population that received annual distribution.

Trial Registration Clinicaltrials.gov NCT00792922

Antibiotics for trachoma

BACKGROUND

Trachoma is the world's leading infectious cause of blindness. In 1996, WHO launched the Alliance for the Global Elimination of Trachoma by the year 2020, based on the 'SAFE' strategy (surgery, antibiotics, facial cleanliness, and environmental improvement).

OBJECTIVES

To assess the evidence supporting the antibiotic arm of the SAFE strategy by assessing the effects of antibiotics on both active trachoma (primary objective), Chlamydia trachomatis infection of the conjunctiva, antibiotic resistance, and adverse effects (secondary objectives).

SEARCH METHODS

We searched relevant electronic databases and trials registers. The date of the last search was 4 January 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that satisfied either of two criteria: (a) trials in which topical or oral administration of an antibiotic was compared to placebo or no treatment in people or communities with trachoma, (b) trials in which a topical antibiotic was compared with an oral antibiotic in people or communities with trachoma. We also included studies addressing different dosing strategies in the population.  DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We identified 14 studies where individuals with trachoma were randomised and 12 cluster-randomised studies. Any antibiotic versus control (individuals)Nine studies (1961 participants) randomised individuals with trachoma to antibiotic or control (no treatment or placebo). All of these studies enrolled children and young people with active trachoma. The antibiotics used in these studies included topical (oxy)tetracycline (5 studies), doxycycline (2 studies), and sulfonamides (4 studies). Four studies had more than two study arms. In general these studies were poorly reported, and it was difficult to judge risk of bias.These studies provided low-certainty evidence that people with active trachoma treated with antibiotics experienced a reduction in active trachoma at three months (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.69 to 0.89; 1961 people; 9 RCTs; I² = 73%) and 12 months (RR 0.74, 95% CI 0.55 to 1.00; 1035 people; 4 RCTs; I² = 90%). Low-certainty evidence was available for ocular infection at three months (RR 0.81, 95% CI 0.63 to 1.04; 297 people; 4 RCTs; I² = 0%) and 12 months (RR 0.25, 95% CI 0.08 to 0.78; 129 people; 1 RCT). None of these studies assessed antimicrobial resistance. In those studies that reported harms, no serious adverse effects were reported (low-certainty evidence).Oral versus topical antibiotics (individuals)Eight studies (1583 participants) compared oral and topical antibiotics. Only one study included people older than 21 years of age. Oral antibiotics included azithromycin (5 studies), sulfonamides (2 studies), and doxycycline (1 study). Topical antibiotics included (oxy)tetracycline (6 studies), azithromycin (1 study), and sulfonamide (1 study). These studies were poorly reported, and it was difficult to judge risk of bias.There was low-certainty evidence of little or no difference in effect between oral and topical antibiotics on active trachoma at three months (RR 0.97, 95% CI 0.81 to 1.16; 953 people; 6 RCTs; I² = 63%) and 12 months (RR 0.93, 95% CI 0.75 to 1.15; 886 people; 5 RCTs; I² = 56%). There was very low-certainty evidence for ocular infection at three or 12 months. Antimicrobial resistance was not assessed. In those studies that reported adverse effects, no serious adverse effects were reported; one study reported abdominal pain with azithromycin; one study reported a couple of cases of nausea with azithromycin; and one study reported three cases of reaction to sulfonamides (low-certainty evidence).Oral azithromycin versus control (communities)Four cluster-randomised studies compared antibiotic with no or delayed treatment. Data were available on active trachoma at 12 months from two studies but could not be pooled because of reporting differences. One study at low risk of bias found a reduced prevalence of active trachoma 12 months after a single dose of azithromycin in communities with a high prevalence of infection (RR 0.58, 95% CI 0.52 to 0.65; 1247 people). The other, lower quality, study in low-prevalence communities reported similar median prevalences of infection at 12 months: 9.3% in communities treated with azithromycin and 8.2% in untreated communities. We judged this moderate-certainty evidence for a reduction in active trachoma with treatment, downgrading one level for inconsistency between the two studies. Two studies reported ocular infection at 12 months and data could be pooled. There was a reduction in ocular infection (RR 0.36, 0.31 to 0.43; 2139 people) 12 months after mass treatment with a single dose compared with no treatment (moderate-certainty evidence). There was high-certainty evidence of an increased risk of resistance of Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli to azithromycin, tetracycline, and clindamycin in communities treated with azithromycin, with approximately 5-fold risk ratios at 12 months. The evidence did not support increased resistance to penicillin or trimethoprim-sulfamethoxazole. None of the studies measured resistance to C trachomatis. No serious adverse events were reported. The main adverse effect noted for azithromycin (˜10%) was abdominal pain, vomiting, and nausea.Oral azithromycin versus topical tetracycline (communities)Three cluster-randomised studies compared oral azithromycin with topical tetracycline. The evidence was inconsistent for active trachoma and ocular infection at three and 12 months (low-certainty evidence) and was not pooled due to considerable heterogeneity. Antimicrobial resistance and adverse effects were not reported.Different dosing strategiesSix studies compared different strategies for dosing. There were: mass treatment at different dosing intervals; applying cessation or stopping rules to mass treatment; strategies to increase mass treatment coverage. There was no strong evidence to support any variation in the recommended annual mass treatment.

AUTHORS' CONCLUSIONS

Antibiotic treatment may reduce the risk of active trachoma and ocular infection in people infected with C trachomatis, compared to no treatment/placebo, but the size of the treatment effect in individuals is uncertain. Mass antibiotic treatment with single dose oral azithromycin reduces the prevalence of active trachoma and ocular infection in communities. There is no strong evidence to support any variation in the recommended periodicity of annual mass treatment. There is evidence of an increased risk of antibiotic resistance at 12 months in communities treated with antibiotics.

The impact on malaria of biannual treatment with azithromycin in children age less than 5 years: a prospective study

Background

The MORDOR study, a cluster randomized clinical trial, showed that single-dose azithromycin (20 mg/kg) administered biannually for 2 years to preschool children reduced mortality; a study was conducted to determine its effect on clinical symptomatic episodes of malaria as a potential mechanism for mortality benefit.

Methods

A randomized control trial (RCT) was conducted, whereby 30 randomly selected communities in Kilosa District, Tanzania were randomized to receive 6-monthly treatment of children ages 1–59 months with single-dose azithromycin (20 mg/kg) vs. placebo. A prospective cohort study was nested within the RCT: children, aged 1 to 35 months at baseline, were randomly selected in each community and evaluated at 6-monthly intervals for 2 years. At each visit, the children were assessed for recent or ongoing fever and anti-malarial treatment; a rapid diagnostic test (RDT) for malaria was performed. The two major outcomes of interest were prevalence of RDT positivity and clinical malaria. The latter was defined as RDT-positivity with fever at time of evaluation and/or reported fever in the 3 days prior to evaluation. Methods that account for correlations at community level and within individuals over time were used to evaluate associations.

Results

At baseline, the prevalence rates in the children in the azithromycin and placebo arms were 17.6% vs. 15.5% for RDT positivity (p = 0.76) and 6.1% vs. 4.3% (p = 0.56) for clinical malaria. There was a decline in both RDT-positivity and clinical malaria over time in both arms. The difference by treatment assignment was not significant for clinical malaria; it was significant for RDT-positivity with greater odds of decline in the placebo arm (p = 0.01).

Conclusions

Lack of evidence for a significant difference in the prevalence of clinical malaria in children at any visit following treatment suggests that the effect of single-dose azithromycin on malaria is at best transient and limited in scope. Chance overrepresentation of non-seasonal transmission in the communities in the azithromycin arm may account for higher rates of RDT-positivity and less decline over time.

Trial registration Clinicaltrials.gov NCT02047981

Ocular Chlamydia trachomatis infection: elimination with mass drug administration

INTRODUCTION

Ocular Chlamydia trachomatis infection, the causative agent for trachoma, is responsible for 1.9 million cases of visual loss worldwide. Mass Drug Administration (MDA) with azithromycin to entire trachoma-endemic districts is part of the World Health Organization's public health strategy for trachoma elimination. Areas covered: Background on C. trachomatis and the epidemiology of trachoma are presented, followed by a review of the antibiotics for treatment and the need for a public health approach to trachoma elimination. The effectiveness of mass drug administration is presented, concluding with challenges to trachoma elimination in the future. Expert opinion: MDA using azithromycin is a key component of the public health strategy for trachoma elimination. With high coverage in children, there is good evidence that MDA drops the community pool of infection. There are challenges to trachoma elimination by the year 2020, and the drug donation program for country MDAs will be integral to ongoing efforts.

Dose and formulation of azithromycin in mass drug administration studies: a systematic review protocol

INTRODUCTION

Azithromycin has been given for tropical infectious diseases such as trachoma and yaws by mass drug administration (MDA). As well as controlling the infectious disease in question, MDA may have a beneficial effect in reducing mortality in young children. However, the dose, formulation, frequency and duration of azithromycin used in certain infectious diseases may vary in different studies, and these differences may have impacts on the effectiveness of azithromycin MDA. Furthermore, whether the dose, formulation, frequency and duration are associated with the effectiveness of azithromycin for reducing child mortality-if indeed this effect can be confirmed-remain unknown. In this study, we will investigate whether different strategies such as different dose, formulation, frequency and duration affect the effectiveness of azithromycin MDA on the prevalence of certain infectious diseases or child mortality.

METHODS AND ANALYSIS

A narrative systematic review will be conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov and WHO International Clinical Trials Registry Platform will be searched. No language restrictions will be applied. All randomised/quasi-controlled trials, observational studies (cross-sectional studies, cohort studies and case-control studies), case series and registered protocols will be considered. Dose, duration, frequency, rounds and formulations of azithromycin used in MDA will be collected and reviewed. The outcomes will be disease prevalence/control in children and child mortality. Data from the individual studies will not be pooled.

ETHICS AND DISSEMINATION

Formal ethical approval is not required since data will be collected from published studies. This systematic review will be published in a peer-reviewed journal and presented at conference meetings.

PROSPERO REGISTRATION NUMBER

CRD42018114902.

Antimicrobial resistance following mass azithromycin distribution for trachoma: a systematic review

Mass azithromycin distribution is a core component of trachoma control programmes and could reduce mortality in children younger than 5 years in some settings. In this systematic review we synthesise evidence on the emergence of antimicrobial resistance after mass azithromycin distribution. We searched electronic databases for publications up to June 14, 2018. We included studies of any type (excluding modelling studies, surveillance reports, and review articles) on community-wide distribution of oral azithromycin for the prevention and treatment of trachoma that assessed macrolide resistance, without restrictions to the type of organism. We extracted prevalence of resistance from published reports and requested unpublished data from authors of included studies. Of 213 identified studies, 19 met inclusion criteria (12 assessed Streptococcus pneumoniae) and were used for qualitative synthesis. Macrolide resistance after azithromycin distribution was reported in three of the five organisms studied. The lack of resistance in Chlamydia trachomatis suggests that azithromycin might remain effective for trachoma programmes, but evidence is scarce. As mass azithromycin distribution for trachoma continues and is considered for other indications, ongoing monitoring of antimicrobial resistance will be required.

Childhood Mortality After Mass Distribution of Azithromycin: A Secondary Analysis of the PRET Cluster-randomized Trial in Niger

BACKGROUND

Mass distributions of azithromycin for trachoma have been associated with secondary benefits, including reductions in child mortality.

METHODS

In the Partnership for the Rapid Elimination of Trachoma cluster-randomized trial in Niger, 24 communities were randomized to annual treatment of everyone and 24 communities were randomized to biannual treatment of children under 12 for 3 years (clinicaltrials.gov, NCT00792922). Treatment was a single dose of directly observed oral azithromycin (20 mg/kg up to 1 g in adults). Vital status was assessed during annual census and monitoring visits. In this prespecified secondary analysis, we compared the mortality rate among children 6 months to less than 5 years of age by treatment arm using negative binomial regression.

RESULTS

Among children 6 months to less than 5 years of age, 404 deaths occurred during the study period. The mortality rate was 35.6 deaths per 1000 person-years (231 deaths, 95% CI: 30.9-40.9) in the annual arm and 29.0 deaths per 1000 person-years (173 deaths, 95% CI: 24.8-33.8) in the biannual arm. The mortality rate ratio comparing children in the biannual arm to the annual arm was 0.81 (95% CI: 0.66-1.00, P = 0.07; primary outcome). The mortality rate ratio comparing children who died from infectious causes in the biannual arm to the annual arm was 0.73 (95% CI: 0.57-0.94; P = 0.02). No adverse events were reported.

CONCLUSIONS

This secondary analysis of a cluster-randomized trial found a nonsignificant 19% decrease in mortality among children 6 months to less than 5 years of age who received biannual azithromycin compared with children who received annual azithromycin. This study was conducted in a high mortality, trachoma-endemic area; thus, results may be specific to this environment only. In addition, the trial was neither designed nor powered to detect a mortality effect, and we cannot rule out the possibility that mortality differences resulted from bias.

Effect of Antibiotics on Short-Term Growth among Children in Burkina Faso: A Randomized Trial

Antibiotics improve both weight and height gain in randomized trials of preschool children with preexisting morbidity. Here, we assess the effect of a short course of three different antibiotics (amoxicillin, azithromycin, and cotrimoxazole) on short-term linear and ponderal growth in a population-based sample of preschool children in rural Burkina Faso. We randomized households with at least two children in the Nouna district, Burkina Faso, to a 5-day course of amoxicillin, azithromycin, cotrimoxazole, or placebo. Within each antibiotic-randomized household, one child was randomly assigned to receive the antibiotic and the other to receive the placebo. Weight and height measurements were taken at baseline and 30 days following the last study medication dose. Weight-for-height Z (WHZ), height-for-age Z (HAZ), and weight-for-age Z (WAZ) scoreswere calculated based on the 2006 World Health Organization standards. Of the 124 households and 248 children enrolled, 229 had anthropometry measurements at 1 month and were analyzed. Children randomized to amoxicillin gained significantly more weight compared with both the placebo household (mean difference 317 g, 95% confidence interval [CI]: 115-519 g) and placebo sibling (mean difference 315 g, 95% CI: 147-482 g) controls. Growth velocity in g/kg/day, and WHZ and WAZ scores were higher in amoxicillin-treated children compared with placebo households and siblings. There were no differences in weight gain in children randomized to azithromycin or cotrimoxazole compared with placebo households or placebo siblings. There were no differences in height gain or HAZ across any of the study arms. Amoxicillin may have short-term growth-promoting effects in healthy children.

Anthropometry and Malaria among Children in Niger: A Cross-Sectional Study

The complex relationship between malnutrition and malaria affects morbidity and mortality in children younger than 5 years, particularly in parts of sub-Saharan Africa where these conditions occur together seasonally. Previous research on this relationship has been inconclusive. Here, we examine the association between anthropometric indicators and malaria infection in a population-based sample of children younger than 5 years in Niger. This cross-sectional study is a secondary analysis of a cluster-randomized trial comparing treatment strategies for trachoma in Niger. We included children aged 6-60 months residing in the 48 communities enrolled in the trial who completed anthropometric and malaria infection assessments at the final study visit. We evaluated the association between anthropometric indicators, including height-for-age z-score (HAZ) and weight-for-age z-score (WAZ) and indicators of malaria infection, including malaria parasitemia and clinical malaria. In May 2013, we collected data from 1,649 children. Of these, 780 (47.3%) were positive for malaria parasitemia and 401 (24.3%) had clinical malaria. In models of malaria parasitemia, the adjusted odds ratio (aOR) was 1.05 (95% confidence interval [CI]: 1.00-1.10) for HAZ and 1.07 (95% CI: 0.99, 1.15) for WAZ. In models of clinical malaria, the aOR was 1.07 (95% CI: 1.02-1.11) for HAZ and 1.09 (95% CI: 1.01-1.19) for WAZ. Overall, we did not find evidence of an association between most anthropometric indicators and malaria infection. Greater height may be associated with an increased risk of clinical malaria.

Annual Versus Biannual Mass Azithromycin Distribution and Malaria Parasitemia During the Peak Transmission Season Among Children in Niger

BACKGROUND

Azithromycin has modest efficacy against malaria, and previous cluster randomized trials have suggested that mass azithromycin distribution for trachoma control may play a role in malaria control. We evaluated the effect of annual versus biannual mass azithromycin distribution over a 3-year period on malaria prevalence during the peak transmission season in a region with seasonal malaria transmission in Niger.

METHODS

Twenty-four communities in Matameye, Niger, were randomized to annual mass azithromycin distribution (3 distributions to the entire community during the peak transmission season) or biannual-targeted azithromycin distribution (6 distributions to children <12 years of age, including 3 in the peak transmission season and 3 in the low transmission season). Malaria indices were evaluated at 36 months during the high transmission season.

RESULTS

Parasitemia prevalence was 42.6% (95% confidence interval: 31.7%-53.6%) in the biannual distribution arm compared with 50.6% (95% confidence interval: 40.3%-60.8%) in the annual distribution arm (P = 0.29). There was no difference in parasite density or hemoglobin concentration in the 2 treatment arms.

CONCLUSIONS

Additional rounds of mass azithromycin distribution during low transmission may not have a significant impact on malaria parasitemia measured during the peak transmission season.

Azithromycin to Reduce Childhood Mortality in Sub-Saharan Africa

BACKGROUND

We hypothesized that mass distribution of a broad-spectrum antibiotic agent to preschool children would reduce mortality in areas of sub-Saharan Africa that are currently far from meeting the Sustainable Development Goals of the United Nations.

METHODS

In this cluster-randomized trial, we assigned communities in Malawi, Niger, and Tanzania to four twice-yearly mass distributions of either oral azithromycin (approximately 20 mg per kilogram of body weight) or placebo. Children 1 to 59 months of age were identified in twice-yearly censuses and were offered participation in the trial. Vital status was determined at subsequent censuses. The primary outcome was aggregate all-cause mortality; country-specific rates were assessed in prespecified subgroup analyses.

RESULTS

A total of 1533 communities underwent randomization, 190,238 children were identified in the census at baseline, and 323,302 person-years were monitored. The mean (±SD) azithromycin and placebo coverage over the four twice-yearly distributions was 90.4±10.4%. The overall annual mortality rate was 14.6 deaths per 1000 person-years in communities that received azithromycin (9.1 in Malawi, 22.5 in Niger, and 5.4 in Tanzania) and 16.5 deaths per 1000 person-years in communities that received placebo (9.6 in Malawi, 27.5 in Niger, and 5.5 in Tanzania). Mortality was 13.5% lower overall (95% confidence interval [CI], 6.7 to 19.8) in communities that received azithromycin than in communities that received placebo (P<0.001); the rate was 5.7% lower in Malawi (95% CI, -9.7 to 18.9), 18.1% lower in Niger (95% CI, 10.0 to 25.5), and 3.4% lower in Tanzania (95% CI, -21.2 to 23.0). Children in the age group of 1 to 5 months had the greatest effect from azithromycin (24.9% lower mortality than that with placebo; 95% CI, 10.6 to 37.0). Serious adverse events occurring within a week after administration of the trial drug or placebo were uncommon, and the rate did not differ significantly between the groups. Evaluation of selection for antibiotic resistance is ongoing.

CONCLUSIONS

Among postneonatal, preschool children in sub-Saharan Africa, childhood mortality was lower in communities randomly assigned to mass distribution of azithromycin than in those assigned to placebo, with the largest effect seen in Niger. Any implementation of a policy of mass distribution would need to strongly consider the potential effect of such a strategy on antibiotic resistance. (Funded by the Bill and Melinda Gates Foundation; MORDOR ClinicalTrials.gov number, NCT02047981 .).

Mass Azithromycin and Malaria Parasitemia in Niger: Results from a Community-Randomized Trial

Studies designed to determine the effects of mass administration of azithromycin on trachoma have suggested that mass azithromycin distributions may also reduce the prevalence of malaria. These studies have typically examined the impact of a small number of treatments over short durations. In this prespecified substudy of a cluster-randomized trial for trachoma, we compared malaria parasitemia prevalence in 24 communities in Niger randomized to receive either annual or biannual mass azithromycin distributions over 3 years. The 12 communities randomized to annual azithromycin received three treatments during the high-transmission season, and the 12 communities randomized to biannual azithromycin received a total of six treatments: three during the high-transmission season and three during the low-transmission season. Blood samples were taken to assess malariometric indices among children in all study communities at a single time point during the high-transmission season after 3 years of the intervention. No significant differences were identified in malaria parasitemia, parasite density, or hemoglobin concentration between the annual and biannual treatment arms. When compared with annual mass azithromycin alone, additional mass azithromycin distributions given during the low-transmission season did not significantly reduce the subsequent prevalence of malaria parasitemia or parasite density after 3 years, as measured during the high-transmission season.

Falciparum Malaria Incidentally Pretreated with Azithromycin

A 65-year-old man, who recently returned from Liberia, visited a clinic complaining of fever, and azithromycin was prescribed. The patient presented to a general hospital 5 days after the onset of symptoms, however, a blood smear examination failed to detect malaria. Contrary to the blood smear result, a rapid antigen test in our hospital was strongly-positive for falciparum malaria, indicating a high level of malarial antigen in the blood. Moreover, laboratory examinations on admission showed a tendency for improvement. We assumed that the administration of azithromycin partially treated malaria, thus complicating the blood smear diagnosis. We should be careful in prescribing azithromycin, which is widely used in clinics, to travelers returning from malaria-endemic countries.