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

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

SUBMITTER: Cairns M

PROVIDER: S-EPMC3621394 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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

Cairns Matthew M Roca-Feltrer Arantxa A Garske Tini T Wilson Anne L AL Diallo Diadier D Milligan Paul J PJ Ghani Azra C AC Greenwood Brian M BM

Nature communications 20120606

Seasonal malaria chemoprevention, previously known as intermittent preventive treatment in children, is highly effective in areas with a short malaria transmission season. Here we assess seasonality in malaria incidence data and define a predictor of seasonality based on rainfall. We then use spatial rainfall, malaria endemicity and population data to identify areas likely to have highly seasonal malaria incidence, and estimate the population at risk and malaria burden in areas where seasonal ma ...[more]

PMID: 22673908

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Project description:BackgroundSeasonal malaria chemoprevention (SMC) is a new strategy recommended by WHO in areas of highly seasonal transmission in March 2012. Although randomized controlled trials (RCTs) have shown SMC to be highly effective, evidence and experience from routine implementation of SMC are limited.MethodsA non-randomized pragmatic trial with pre-post design was used, with one intervention district (Kita), where four rounds of SMC with sulfadoxine + amodiaquine (SP + AQ) took place in August-November 2014, and one comparison district (Bafoulabe). The primary aims were to evaluate SMC coverage and reductions in prevalence of malaria and anaemia when SMC is delivered through routine programmes using existing community health workers. Children aged 3-59 months from 15 selected localities per district, sampled with probability proportional to size, were surveyed and blood samples collected for malaria blood smears, haemoglobin (Hb) measurement, and molecular markers of drug resistance in two cross-sectional surveys, one before SMC (July 2014) and one after SMC (December 2014). Difference-in-differences regression models were used to assess and compare changes in malaria and anaemia in the intervention and comparison districts. Adherence and tolerability of SMC were assessed by cross-sectional surveys 4-7 days after each SMC round. Coverage of SMC was assessed in the post-SMC survey.ResultsDuring round 1, 84% of targeted children received at least the first SMC dose, but coverage declined to 67% by round 4. Across the four treatment rounds, 54% of children received four complete SMC courses. Prevalence of parasitaemia was similar in intervention and comparison districts prior to SMC (23.4 vs 29.5%, p = 0.34) as was the prevalence of malaria illness (2.4 vs 1.9%, p = 0.75). After SMC, parasitaemia prevalence fell to 18% in the intervention district and increased to 46% in the comparison district [difference-in-differences (DD) OR = 0.35; 95% CI 0.20-0.60]. Prevalence of malaria illness fell to a greater degree in the intervention district versus the comparison district (DD OR = 0.20; 95% CI 0.04-0.94) and the same for moderate anaemia (Hb < 8 g/dL) (DD OR = 0.26, 95% CI 0.11-0.65). The frequency of the quintuple mutation (dhfr N51I, C59R and S108N + dhps A437G and K540E) remained low (5%) before and after intervention in both districts.ConclusionsRoutine implementation of SMC in Mali substantially reduced malaria and anaemia, with reductions of similar magnitude to those seen in previous RCTs. Improving coverage could further strengthen SMC impact. Trial registration clinical trial registration number NCT02894294.

Project description:BACKGROUND:Seasonal malaria chemoprevention is widely implemented in Sahel and sub-Sahel countries in Africa. Few studies have assessed the impact of the SMC on hospital admission and death when it is implemented in the health system. This retrospective study assessed the impact of seasonal malaria chemoprevention (SMC) on hospitalizations and deaths of children under 5 years of age during the second year of implementation of SMC in the health district of Ouelessebougou in Mali. METHODS:In February 2017, a survey was conducted to assess hospital admissions and deaths in children under 5 years of age in two health sub-districts where SMC was implemented in 2015 and two health sub-districts where SMC was not implemented. The survey reviewed deaths and hospitalizations of children under 5, in the four health sub-districts. The crude and specific incidence rates of hospitalizations and deaths were determined in both groups and expressed per 1000 children per year. A negative binomial regression model and a Cox model were used to estimate the relative risks of hospitalization and death after adjusting for confounders. The R software was used for data analysis. RESULTS:A total of 6638 children under 5 years of age were surveyed, 2759 children in the SMC intervention areas and 3879 children in the control areas. All causes mortality rate per 1000 person-years was 8.29 in the control areas compared to 3.63 in the intervention areas; age and gender adjusted mortality rate ratio 0.44 (95% CI 0.22-0.91), p = 0.027. The incidence rate of all causes hospital admissions was 19.60 per 1000 person-years in the intervention group compared to 33.45 per 1000 person-years in the control group, giving an incidence rate ratio (IRR) adjusted for age and gender of 0.61 (95% CI 0.44-0.84), p = 0.003. CONCLUSION:The implementation of SMC was associated with a substantial reduction in hospital admissions and all-cause mortality. Trial registration ClinicalTrials.gov NCT02646410.

Project description:BackgroundMalaria and anemia remain major public health challenges in Tanzania. Household socioeconomic factors are known to influence these conditions. However, it is not clear how these factors influence malaria transmission and anemia in Masasi and Nanyumbu Districts. This study presents findings on malaria and anemia situation in under-five children and its influencing socioeconomic factors in Masasi and Nanyumbu Districts, surveyed as part of an ongoing seasonal malaria chemoprevention operational study.MethodsA community-based cross-sectional survey was conducted between August and September 2020. Finger-prick blood samples collected from children aged 3-59 months were used to test for malaria infection using malaria rapid diagnostic test (mRDT), thick smears for determination of asexual and sexual parasitemia, and thin smear for parasite speciation. Hemoglobin concentration was measured using a HemoCue spectrophotometer. A structured questionnaire was used to collect household socioeconomic information from parents/caregivers of screened children. The prevalence of malaria was the primary outcome. Chi-square tests, t-tests, and logistic regression models were used appropriately.ResultsOverall mRDT-based malaria prevalence was 15.9% (373/2340), and was significantly higher in Nanyumbu (23.7% (167/705) than Masasi District (12.6% (206/1635), p<0.001. Location (Nanyumbu), no formal education, household number of people, household number of under-fives, not having a bed net, thatched roof, open/partially open eave, sand/soil floor, and low socioeconomic status were major risks for malaria infection. Some 53.9% (1196/2218) children had anemia, and the majority were in Nanyumbu (63.5% (458/705), p<0.001. Location (Nanyumbu), mRDT positive, not owning a bed net, not sleeping under bed net, open/partially open eave, thatched window, sex of the child, and age of the child were major risk factors for anemia.ConclusionPrevalence of malaria and anemia was high and was strongly associated with household socioeconomic factors. Improving household socioeconomic status is expected to reduce the prevalence of the conditions in the area.

Project description:Seasonal Malaria Chemoprevention (SMC) is recommended for children under 5 in the Sahel and sub-Sahel. The burden in older children may justify extending the age range, as has been done effectively in Senegal. We examine costs of door-to-door SMC delivery to children up to 10?years by community health workers (CHWs). We analysed incremental financial and economic costs at district level and below from a health service perspective. We examined project accounts and prospectively collected data from 405 CHWs, 46 health posts, and 4 district headquarters by introducing questionnaires in advance and completing them after each monthly implementation round. Affordability was explored by comparing financial costs of SMC to relevant existing health expenditure levels. Costs were disaggregated by administration month and by health service level. We used linear regression models to identify factors associated with cost variation between health posts. The financial cost to administer SMC to 180?000 children over one malaria season, reaching ?93% of children with all three intended courses of SMC was $234?549 (constant 2010 USD) or $0.50 per monthly course administered. Excluding research-participation incentives, the financial cost was $0.32 per resident (all ages) in the catchment area, which is 1.2% of Senegal's general government expenditure on health per capita. Economic costs were 18.7% higher than financial costs at $278?922 or $0.59 per course administered and varied widely between health posts, from $0.38 to $2.74 per course administered. Substantial economies of scale across health posts were found, with the smallest health posts incurring highest average costs per monthly course administered. SMC for children up to 10 is likely to be affordable, particularly where it averts substantial curative care costs. Estimates of likely costs and cost-effectiveness of SMC in other contexts must account for variation in average costs across delivery months and health posts.

Project description:INTRODUCTION:Seasonal malaria chemoprevention (SMC), with sulphadoxine-pyrimethamine plus amodiaquine (SP+AQ) is effective but does not provide complete protection against clinical malaria. The RTS,S/AS01E malaria vaccine provides a high level of protection shortly after vaccination, but this wanes rapidly. Such a vaccine could be an alternative or additive to SMC. This trial aims to determine whether seasonal vaccination with RTS,S/AS01E vaccine could be an alternative to SMC and whether a combination of the two interventions would provide added benefits. METHODS AND ANALYSIS:This is an individually randomised, double-blind, placebo-controlled trial. 5920 children aged 5-17 months were enrolled in April 2017 in Mali and Burkina Faso. Children in group 1 received three priming doses of RTS,S/AS01E vaccine before the start of the 2017 malaria transmission season and a booster dose at the beginning of two subsequent transmission seasons. In addition, they received SMC SP+AQ placebo on four occasions each year. Children in group 2 received three doses of rabies vaccine in year 1 and hepatitis A vaccine in years 2 and 3 together with four cycles of SMC SP+AQ?each year. Children in group 3 received RTS,S/AS01E vaccine and four courses of SMC SP+AQ. Incidence of clinical malaria is determined by case detection at health facilities. Weekly active surveillance for malaria is undertaken in a randomly selected subset of children. The prevalence of malaria is measured in surveys at the end of each transmission season. The primary endpoint is the incidence of clinical malaria confirmed by a positive blood film with a minimum parasite density of 5000 /µL. Primary analysis will be by modified intention to treat defined as children who have received the first dose of the malaria or control vaccine. ETHICS AND DISSEMINATION:The protocol was approved by the national ethics committees of Mali and Burkina Faso and the London School of Hygiene and Tropical Medicine. The results will be presented to all stakeholders and published in open access journals. TRIAL REGISTRATION NUMBER:NCT03143218; Pre-results.

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

Publications

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

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