Optimal mode for delivery of seasonal malaria chemoprevention in Ouelessebougou, Mali: A cluster randomized trial

Predictors of accessing seasonal malaria chemoprevention medicines through non-door-to-door distribution in Nigeria

BACKGROUND

In Nigeria, seasonal malaria chemoprevention (SMC) is typically administered door-to-door to children under five by community medicine distributors during high transmission seasons. While door-to-door distribution (DDD) is exclusively employed in Nigeria as part of standard operating procedures of SMC programmes, some households access SMC through non-DDD channels, such as fixed-point distributions, health facilities, and private purchase. However, analysis of access to SMC medicines through non-DDD has been limited, with little evidence of its outcomes on adherence to the three-day complete course of SMC medicines and caregiver actions in the event of adverse reactions to SMC medicines.

METHODS

Data were obtained from SMC end-of-round coverage surveys conducted in Nigeria in 2021 and 2022, including 25,278 households for the analysis. The proportion of households accessing SMC medicine through non-DDD and the distribution of various non-DDD sources of SMC medicines were described. Multivariate random-effects logistic regression models were performed to identify predictors of accessing SMC medicines through non-DDD. The associations between non-DDD, and caregiver-reporting of adherence to complete administration of SMC medicines and caregiver actions in the event of adverse reactions to SMC medicines were also assessed.

RESULTS

Less than 2% (314/24003) of households accessed SMC medicines through non-DDD in the states surveyed. Over 60% of non-DDD access was via health facility personnel and community medicine distributors from different locations. Variables associated with non-DDD access included heads of household being born in the local state (OR = 0.68, 95% CI 0.47 to 0.90), households residing in the study state since the first cycle of the SMC round (OR = 0.39, 95% CI 0.17 to 0.88), households with high wealth index (OR = 1.36, 95% CI 1.01 to 1.82), and caregivers hearing about date of SMC delivery in the previous cycle (OR = 0.18, 95%CI 0.14 to 0.24). Furthermore, non-DDD was associated with reduced SMC adherence and higher caregiver non-reporting of adverse reactions to SMC medicines in children compared with DDD.

CONCLUSION

This study provides evidence on the characteristics of households accessing SMC medicines through non-DDD and its potential negative outcomes on adherence to SMC medicine and adverse reaction reporting, underscoring potential implementation issues that may arise if non-DDD delivery models are adopted in SMC, particularly in places where DDD had been firstly used.

Contextual Factors to Improve Implementation of Malaria Chemoprevention in Children: A Systematic Review

Malaria remains a leading cause of childhood morbidity and mortality in sub-Saharan Africa, particularly among children under 5 years of age. To help address this challenge, the WHO recommends chemoprevention for certain populations. For children and infants, the WHO recommends seasonal malaria chemoprevention (SMC), perennial malaria chemoprevention (PMC; formerly intermittent preventive treatment in infants [IPTi]), and, more recently, intermittent preventive treatment in school children (IPTsc). This review describes the contextual factors, including feasibility, acceptability, health equity, financial considerations, and values and preferences, that impact implementation of these strategies. A systematic search was conducted on July 5, 2022, and repeated April 13, 2023, to identify relevant literature. Two reviewers independently screened titles for eligibility, extracted data from eligible articles, and identified and summarized themes. Of 6,295 unique titles identified, 65 were included. The most frequently evaluated strategy was SMC (n = 40), followed by IPTi (n = 18) and then IPTsc (n = 6). Overall, these strategies were highly acceptable, although with IPTsc, there were community concerns with providing drugs to girls of reproductive age and the use of nonmedical staff for drug distribution. For SMC, door-to-door delivery resulted in higher coverage, improved caregiver acceptance, and reduced cost. Lower adherence was noted when caregivers were charged with giving doses 2 and 3 unsupervised. For SMC and IPTi, travel distances and inclement weather limited accessibility. Sensitization and caregiver education efforts, retention of high-quality drug distributors, and improved transportation were key to improving coverage. Additional research is needed to understand the role of community values and preferences in chemoprevention implementation.

A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda

Background

The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SPAQ) for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist.

Objective

The study aims to test the effectiveness of SMC with Dihydroartemisinin-piperaquine (DP) or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal.

Methods

A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3-59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation.

Discussion

This study evaluates the effects of SPAQ-SMC versus DP-SMC on clinical malaria in vulnerable children in the context of high parasite SP resistance, whilst informing on the best implementation strategies.

Conclusion

This study will inform malaria policy in high-burden countries, specifically on utility of SMC outside the sahel, and contribute to progress in malaria control.

Comparison of door-to-door and fixed-point delivery of azithromycin distribution for child survival in Niger: A cluster-randomized trial

Recent evidence indicates mass azithromycin distribution reduces under-5 mortality. This intervention is being considered for child survival programs in high mortality sub-Saharan African settings. The delivery approach used in prior studies required a full-time census and distribution team, which is not feasible for most programs. To determine the optimal programmatic approach to delivery, this study aimed to compare treatment coverage, costs, and acceptability of different delivery approaches with existing community health workers (CHWs). This cluster-randomized trial included rural and peri-urban communities in Dosso, Niger (clinicaltrials.gov, NCT04774991). A random sample of 80 eligible communities was randomized 1:1 to biannual door-to-door or fixed-point delivery of oral azithromycin to children 1-59 months old over 1 year. Data analysts alone were masked given the nature of the intervention. The primary outcome was community-level treatment coverage defined as the number of children treated recorded by CHWs divided by the number of eligible children determined using a post-distribution census. Costs were monitored through routine administrative data collection and micro-costing. The census included survey questions on intervention acceptability among caregivers, community leaders, and CHWs. After randomization, 1 community was excluded due to inaccuracies in available administrative data, resulting in 39 communities receiving door-to-door delivery. At the second distribution, community-level mean treatment coverage was 105% (SD 44%) in the door-to-door arm and 92% (SD 20%) in the fixed-point arm (Mean difference 13%, 95% CI -2% to 28%, P-value = 0.08). The total cost per dose delivered was $1.91 in the door-to-door arm and $2.51 in the fixed-point arm. Indicators of acceptability were similar across stakeholder groups in both arms, with most respondents in each group indicating a preference for door-to-door. Overall, door-to-door delivery is the preferred approach to azithromycin distribution in this setting and might reach more children at a lower cost per dose delivered than fixed-point. Trial Registration: clinicaltrials.gov NCT04774991.

Seasonal malaria chemoprevention in Africa and China's upgraded role as a contributor: a scoping review

BACKGROUND

Children under five are the vulnerable population most at risk of being infected with Plasmodium parasites, especially in the Sahel region. Seasonal malaria chemoprevention (SMC) recommended by World Health Organization (WHO), has proven to be a highly effective intervention to prevent malaria. Given more deaths reported during the COVID-19 pandemic than in previous years due to the disruptions to essential medical services, it is, therefore, necessary to seek a more coordinated and integrated approach to increasing the pace, coverage and resilience of SMC. Towards this end, fully leverage the resources of major players in the global fight against malaria, such as China could accelerate the SMC process in Africa.

METHODS

We searched PubMed, MEDLINE, Web of Science, and Embase for research articles and the Institutional Repository for Information Sharing of WHO for reports on SMC. We used gap analysis to investigate the challenges and gaps of SMC since COVID-19. Through the above methods to explore China's prospective contribution to SMC.

RESULTS

A total of 68 research articles and reports were found. Through gap analysis, we found that despite the delays in the SMC campaign, 11.8 million children received SMC in 2020. However, there remained some challenges: (1) a shortage of fully covered monthly courses; (2) lack of adherence to the second and third doses of amodiaquine; (3) four courses of SMC are not sufficient to cover the entire malaria transmission season in areas where the peak transmission lasts longer; (4) additional interventions are needed to consolidate SMC efforts. China was certified malaria-free by WHO in 2021, and its experience and expertise in malaria elimination can be shared with high-burden countries. With the potential to join the multilateral cooperation in SMC, including the supply of quality-assured health commodities, know-how transfer and experience sharing, China is expected to contribute to the ongoing scale-up of SMC.

CONCLUSIONS

A combination of necessary preventive and curative activities may prove beneficial both for targeted populations and for health system strengthening in the long run. More actions are entailed to promote the partnership and China can be one of the main contributors with various roles.

Updates on Malaria Epidemiology and Prevention Strategies

Purpose of Review

The objective of this review was to provide an update on recent malaria epidemiology, both globally and in non-endemic areas, to identify the current distribution and repercussions of genetically diverse Plasmodium species and summarize recently implemented intervention and prevention tools.

Recent Findings

Notable changes in malaria epidemiology have occurred in recent years, with an increase in the number of total cases and deaths globally during 2020-2021, in part attributed to the COVID-19 pandemic. The emergence of artemisinin-resistant species in new areas and the expanding distribution of parasites harbouring deletions of the pfhrp2/3 genes have been concerning. New strategies to curb the burden of this infection, such as vaccination, have been implemented in certain endemic areas and their performance is currently being evaluated.

Summary

Inadequate control of malaria in endemic regions may have an effect on imported malaria and measures to prevent re-establishment of transmission in malaria-free areas are essential. Enhanced surveillance and investigation of Plasmodium spp. genetic variations will contribute to the successful diagnosis and treatment of malaria in future. Novel strategies for an integrated One Health approach to malaria control should also be strengthened.

Facilitators and barriers to seasonal malaria chemoprevention (SMC) uptake in Nigeria: a qualitative approach

BACKGROUND

SMC was adopted in Nigeria in 2014 and by 2021 was being implemented in 18 states, over four months between June and October by 143000 community drug distributors (CDDs) to a target population of 23million children. Further expansion of SMC is planned, extending to 21 states with four or five monthly cycles. In view of this massive scale-up, the National Malaria Elimination Programme undertook qualitative research in five states shortly after the 2021 campaign to understand community attitudes to SMC so that these perspectives inform future planning of SMC delivery in Nigeria.

METHODS

In 20 wards representing urban and rural areas with low and high SMC coverage in five states, focus group discussions were held with caregivers, and in-depth interviews conducted with community leaders and community drug distributors. Interviews were also held with local government area and State malaria focal persons and at national level with the NMEP coordinator, and representatives of partners working on SMC in Nigeria. Interviews were recorded and transcribed, those in local languages translated into English, and transcripts analysed using NVivo software.

RESULTS

In total, 84 focus groups and 106 interviews were completed. Malaria was seen as a major health concern, SMC was widely accepted as a key preventive measure, and community drug distributors (CDDs) were generally trusted. Caregivers preferred SMC delivered door-to-door to the fixed-point approach, because it allowed them to continue daily tasks, and allowed time for the CDD to answer questions. Barriers to SMC uptake included perceived side-effects of SMC drugs, a lack of understanding of the purpose of SMC, mistrust and suspicions that medicines provided free may be unsafe or ineffective, and local shortages of drugs.

CONCLUSIONS

Recommendations from this study were shared with all community drug distributors and others involved in SMC campaigns during cascade training in 2022, including the need to strengthen communication about the safety and effectiveness of SMC, recruiting distributors from the local community, greater involvement of state and national level pharmacovigilance coordinators, and stricter adherence to the planned medicine allocations to avoid local shortages. The findings reinforce the importance of retaining door-to-door delivery of SMC.

A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda

Background: The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist. Objective: The study aims to test the effectiveness of SMC with DP or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal. Methods: A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent  infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3–59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation. Discussion: This study evaluates the effects of a clinical intervention on relevant outcomes whilst collecting information on implementation. Conclusion: This study will inform malaria policy in high-burden countries and contribute to progress in malaria control.

Analysis of attitudes and practices influencing adherence to seasonal malaria chemoprevention in children under 5 years of age in the Dosso Region of Niger

BACKGROUND

Seasonal malaria chemoprevention (SMC) consists of the intermittent administration of a 3 day course of anti-malarial medications during the months of highest malaria risk in the Sahel region, where malaria transmission is highly seasonal. SMC is an effective intervention to reduce episodes of uncomplicated and severe malaria in children. However, morbidity cannot be lowered without adherence to medications. The objective of this study was to examine SMC medication adherence and to identify the attitudes and practices of caregivers during the 2020 SMC campaign in the Dosso region.

METHODS

This study was conducted based on data from independent monitoring using random cluster sampling. Adherence levels and the attitudes and practices of caregivers were evaluated using data from caregivers' self-reports and analysed according to Bernard Vrijens' taxonomy.

RESULTS

At the initiation of treatment phase, 99% of children (N = 2296) received their first administration of medication, with 90% of caregivers (N = 1436) knowing that the medications help prevent malaria. However, only 56% of caregivers (N = 1856) reported that treatment initiation took place under direct observation by the distributor. At the implementation of treatment phase, 90% of children (N = 2132) took their medication on the second day and 84% (N = 1068) took it the third day. "Forgetting," "not having time," and "the mother's absence" were the main reasons caregivers gave to explain discontinuation of the 3 day course of medication.

CONCLUSION

This simple, low-cost survey demonstrated that coverage of SMC and adherence by caregivers to completing the full 3 day medication course was high. The survey also showed that knowledge, attitudes, and practices of some caregivers regarding adherence to medications during the SMC campaign could be improved. Expanding distributors' training, developing and providing them with tools for interpersonal communication, and strengthening supervision could lead to even higher adherence.

Factors Influencing Second and Third Dose Observance during Seasonal Malaria Chemoprevention (SMC): A Quantitative Study in Burkina Faso, Mali and Niger

This study aims to evaluate the factors influencing the adherence to the 2nd and 3rd doses of Amodiaquine (AQ) during seasonal malaria chemoprevention (SMC) in Burkina Faso, Mali, and Niger. Overall, 3132 people were interviewed during surveys between 2019 and 2020 in 15 health districts. In Burkina Faso, Mali, and Niger, the proportions of non-adherence were 4.15%, 5.60%, and 13.30%, respectively, for the 2nd dose and 3.98%, 5.60% and 14.39% for the 3rd dose. The main cause of non-adherence to the 2nd and 3rd doses was other illnesses in 28.5% and 29.78%, respectively, in Burkina Faso, 5.35% and 5.35% in Mali and 1.6% and 0.75% in Niger. It was followed by vomiting in 12.24% and 10.63% for Burkina and 2.45% and 3.78% in Niger. The last cause was refusal in 6.12% and 4.25% in Burkina, 33.9% and 15.25% in Mali and 0.8% and 1.51% in Niger. Non-adherence of doses related to parents was primarily due to their absence in 28.5% and 27.65% in Burkina, 16.07% and 16.07% in Mali and 7.37% and 6.06% in Niger. Traveling was the second cause related to parents in 12.24% and 12.76% in Burkina, 19.64% and 19.64% in Mali and 0.81% and 0.75% in Niger. Non-adherence related to community distributors was mainly due to missing the doses in 4.08% and 4.25% in Burkina, 23.21% and 23.21% in Mali, 77.04% and 76.51% in Niger. Our study reported very small proportions of non-adherence to 2nd and 3rd doses of SMC and identified the main causes of non-adherence. These findings will provide helpful information for policymakers and public health authorities to improve adherence to SMC

Effect of three years' seasonal malaria chemoprevention on molecular markers of resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine and amodiaquine in Ouelessebougou, Mali

Background

In 2012, seasonal malaria chemoprevention (SMC) was recommended as policy for malaria control by the World Health Organization (WHO) in areas of highly seasonal malaria transmission across the Sahel sub-region in Africa along with monitoring of drug resistance. We assessed the long-term impact of SMC on Plasmodium falciparum resistance to sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) over a 3-year period of SMC implementation in the health district of Ouelessebougou, Mali.

Methods

In 8 randomly selected sub-districts of Ouelessebougou, Mali, children aged 0–5 years were randomly selected during cross-sectional surveys at baseline (August 2014) and 1, 2 and 3 years post-SMC, at the beginning and end of the malaria transmission season. Blood smears and blood spots on filter paper were obtained and frequencies of mutation in P. falciparum genes related to resistance to SP and AQ (Pfdhfr, Pfdhps, Pfmdr1, and Pfcrt) were assessed by PCR amplification on individual samples and PCR amplification followed by deep sequencing on pooled (by site and year) samples.

Results

At each survey, approximately 50–100 individual samples were analysed by PCR amplification and a total of 1,164 samples were analysed by deep sequencing with an average read depth of 18,018–36,918 after pooling by site and year. Most molecular markers of resistance did not increase in frequency over the period of study (2014–2016). After 3 years of SMC, the frequencies of Pfdhps 540E, Pfdhps 437G and Pfcrt K76T remained similar compared to baseline (4.0 vs 1.4%, p = 0.41; 74.5 vs 64.6%, p = 0.22; 71.3 vs 67.4%, p = 0.69). Nearly all samples tested carried Pfdhfr 59R, and this proportion remained similar 3 years after SMC implementation (98.8 vs 100%, p = 1). The frequency of Pfmdr1 N86Y increased significantly over time from 5.6% at baseline to 18.6% after 3 years of SMC (p = 0.016). Results of pooled analysis using deep sequencing were consistent with those by individual analysis with standard PCR, but also indicated for the first time the presence of mutations at the Pfdhps A581G allele at a frequency of 11.7% after 2 years of SMC, as well as the Pfdhps I431V allele at frequencies of 1.6–9.3% following 1 and 2 years of SMC, respectively.

Conclusion

Two and 3 years of SMC implementation were associated with increased frequency of the Pfmdr1 N86Y mutation but not Pfdhps 540E, Pfdhps 437G and Pfcrt K76T. The first-time detection of the Pfdhps haplotype bearing the I431V and A581G mutations in Mali, even at low frequency, warrants further long-term surveillance.

Estimating malaria chemoprevention and vector control coverage using program and campaign data: A scoping review of current practices and opportunities

Background

Accurate estimation of intervention coverage is a vital component of malaria program monitoring and evaluation, both for process evaluation (how well program targets are achieved), and impact evaluation (whether intervention coverage had an impact on malaria burden). There is growing interest in maximizing the utility of program data to generate interim estimates of intervention coverage in the periods between large-scale cross-sectional surveys (the gold standard). As such, this study aimed to identify relevant concepts and themes that may guide future optimization of intervention coverage estimation using routinely collected data, or data collected during and following intervention campaigns, with a particular focus on strategies to define the denominator.

Methods

We conducted a scoping review of current practices to estimate malaria intervention coverage for insecticide-treated nets (ITNs); indoor residual spray (IRS); intermittent preventive treatment in pregnancy (IPTp); mass drug administration (MDA); and seasonal malaria chemoprevention (SMC) interventions; case management was excluded. Multiple databases were searched for relevant articles published from January 1, 2015 to June 1, 2018. Additionally, we identified and included other guidance relevant to estimating population denominators, with a focus on innovative techniques.

Results

While program data have the potential to provide intervention coverage data, there are still substantial challenges in selecting appropriate denominators. The review identified a lack of consistency in how coverage was defined and reported for each intervention type, with denominator estimation methods not clearly or consistently reported, and denominator estimates rarely triangulated with other data sources to present the feasible range of denominator values and consequently the range of likely coverage estimates.

Conclusions

Though household survey-based estimates of intervention coverage remain the gold standard, efforts should be made to further standardize practices for generating interim measurements of intervention coverage from program data, and for estimating and reporting population denominators. This includes fully describing any projections or adjustments made to existing census or population data, exploring opportunities to validate available data by comparing with other sources, and explaining how the denominator has been restricted (or not) to reflect exclusion criteria.

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

Background

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

Methods

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

Results

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

Conclusion

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

A microplanning model to improve door-to-door health service delivery: the case of Seasonal Malaria Chemoprevention in Sub-Saharan African villages

Background

Malaria incidence has plateaued in Sub-Saharan Africa despite Seasonal Malaria Chemoprevention’s (SMC) introduction. Community health workers (CHW) use a door-to-door delivery strategy to treat children with SMC drugs, but for SMC to be as effective as in clinical trials, coverage must be high over successive seasons.

Methods

We developed and used a microplanning model that utilizes population raster to estimate population size, generates optimal households visit itinerary, and quantifies SMC coverage based on CHWs’ time investment for treatment and walking. CHWs’ performance under current SMC deployment mode was assessed using CHWs’ tracking data and compared to microplanning in villages with varying demographics and geographies.

Results

Estimates showed that microplanning significantly reduces CHWs’ walking distance by 25%, increases the number of visited households by 36% (p < 0.001) and increases SMC coverage by 21% from 37.3% under current SMC deployment mode up to 58.3% under microplanning (p < 0.001). Optimal visit itinerary alone increased SMC coverage up to 100% in small villages whereas in larger or hard-to-reach villages, filling the gap additionally needed an optimization of the CHW ratio.

Conclusion

We estimate that for a pair of CHWs, the daily optimal number of visited children (assuming 8.5mn spent per child) and walking distance should not exceed 45 (95% CI 27–62) and 5 km (95% CI 3.2–6.2) respectively. Our work contributes to extend SMC coverage by 21–63% and may have broader applicability for other community health programs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-020-05972-2.

Treatment and prevention of malaria in children

Malaria disproportionately affects children younger than 5 years. Falciparum malaria is responsible for more than 200 000 child deaths per year in Africa and vivax malaria is well documented as a cause of severe anaemia and excess mortality in children in Asia and Oceania. For the treatment of malaria in children, paediatric dosing recommendations for several agents, including parenteral artesunate and dihydroartemisinin-piperaquine, have belatedly been shown to be suboptimal. Worsening antimalarial resistance in Plasmodium falciparum in the Greater Mekong Subregion threatens to undermine global efforts to control malaria. Triple antimalarial combination therapies are being evaluated to try to impede this threat. The RTS,S/AS01 vaccine gives partial protection against falciparum malaria and is being evaluated in large, pilot studies in Ghana, Malawi, and Kenya as a complementary tool to other preventive measures. Seasonal malaria chemoprevention in west Africa has resulted in declines in malaria incidence and deaths and there is interest in scaling up efforts by expanding the age range of eligible recipients. Preventing relapse in Plasmodium vivax infection with primaquine is challenging because treating children who have G6PD deficiency with primaquine can cause acute haemolytic anaemia. The safety of escalating dose regimens for primaquine is being studied to mitigate this risk.

The program and policy change framework: A new tool to measure research use in low- and middle-income countries

Organizations that fund research to address global development challenges are increasingly interested in measuring the social and economic outcomes of research. However, traditional metrics for measuring research outputs are often insufficient for capturing the outcomes targeted by international assistance organizations. To address this, the Center for Development Research (CDR), part of the U.S. Global Development Lab at the United States Agency for International Development (USAID), has designed a new tool: the Program and Policy Change (PPC) framework for tracking and quantifying the influence of research on program and policy change in international development. The framework draws on existing conceptual frameworks of evidence uptake and the literature on policy change. This article describes the design of the PPC framework and presents the results of applying the framework to two USAID research programs. The benefits of the framework include applicability across research sectors, focus on evidence-informed policy at various levels of geographical influence, and inclusion of a numeric scoring system that enables quantification of outcomes.

Impacts of Seasonal Malaria Chemoprevention on Malaria Burden among under Five-Year-Old Children in Borno State, Nigeria

Malaria disproportionately affects all ages with a high burden among children below five years. Thus, control measures are deployed including Seasonal Malaria Chemoprevention (SMC). The present study assessed the impacts of SMC on malaria burden among subjects aged 3–59 months in Borno State, Nigeria. Twenty (20) clusters were randomly selected from accessible 16 Local Government Areas (LGAs) of Borno State, Nigeria, and SMC was deployed in 10 of the clusters by administering a full dose of amodiaquine plus sulfadoxine-pyrimethamine at monthly intervals for 4 months consecutively. Three hundred and ninety-nine children were enrolled in the study. A structured questionnaire was used to obtain demographic and malaria-related data. Thick blood smear, thin blood smear, and capillary sample were collected two weeks after the 4^th cycle of SMC. The prevalence of malaria and anaemia was determined among the subjects and for the clusters. The proportions of the female (46.4%; 185/399) and male (53.6%; 214/399) subjects were similar (p > 0.05) with subjects aged 24–47 months (35.8%; 143/399) accounting for the highest proportion (p < 0.05). Malaria prevalence was 10.3% (41/399) and was higher among non-SMC subjects (15.9%; 31/195) than among SMC subjects (4.9%; 10/204) (p < 0.05, df = 1, χ² = 10.8). Malaria prevalence was higher in non-SMC clusters (80.0%; 8/10) than in SMC clusters (30.0%; 3/10) (p < 0.05, df = 1, χ² = 40.5). The mean haematocrit of the 399 subjects was 34.0 ± 5.3% with an anaemia prevalence of 18.1% (72/399). The mean haematocrit was higher among SMC subjects (35.4 ± 5.0% vs. 33.1 ± 4.2%; p < 0.05) while anaemia prevalence was higher among non-SMC subjects (21.5% vs. 14.6%; p < 0.05, df = 1, χ² = 2.8). Of the SMC subjects, 4.9% reported adverse drug reactions. SMC is safe and significantly reduced malaria burden among children in Borno State, and thus, the measure could be deployed in the state for effective malaria control.

Effect of routine seasonal malaria chemoprevention on malaria trends in children under 5 years in Dangassa, Mali

BACKGROUND

Seasonal malaria chemoprevention (SMC) is a new strategy to prevent malaria in children under 5 years old. It has been recommended by the World Health Organization since 2012 in malaria-endemic areas with seasonal transmission. This study aimed to assess the changes in malaria indicators through two consecutive years of SMC routine implementation in children under 5 years old in Dangassa, where malaria is endemic with a long and high transmission season.

METHODS

From 2012 to 2016, a cohort study was conducted in Dangassa village. The study team based in the village followed all malaria clinical cases in children under 5 years old at the community health centre. During the study, SMC was routinely implemented in collaboration with the National Malaria Control Programme. The Cox regression model was used in order to compare malaria risk during the study.

RESULTS

The Cox regression model showed a significant reduction in malaria clinical incidence, both in 2015 (HR = 0.27 (0.18-0.40), 95% CI) and in 2016 (HR = 0.23 (0.15-0.35), 95% CI) of SMC implementation compared to October 2013. Gametocyte and fever prevalence was lower between September and October during SMC implementation (2015 and 2016) compared to the same period before SMC implementation (2013-2014). A slight increase of malaria incidence was observed in December at the end of SMC implementation.

CONCLUSION

SMC has significantly reduced both malaria incidence and gametocyte prevalence and improved haemoglobin levels in children under 5 years old after 2 years of routine implementation.

Malaria epidemiology in Kobeni department, southeastern Mauritania from 2015 to 2017

Background

Plasmodium falciparum malaria is endemic in the southern sahelian zone of Mauritania where intense internal and trans-border human and livestock movement occurs. The risk of importation and spread of drug-resistant parasites need to be regularly assessed in this region. The objective of the study was to assess the recent malaria situation near the Mauritania-Mali border.

Methods

Between February 2015 and December 2017, patients with fever or history of fever during the previous 48 h, presenting at the health centre of Kobeni city, were screened for malaria using a rapid diagnostic test (RDT) and microscopic examination of blood smears. The diagnosis was later confirmed by PCR. Cohen’s kappa statistics was used to estimate the degree of agreement between diagnostic methods. Fisher’s exact test was used to compare proportions. The odds ratio was calculated to measure the association between the use of bed nets and malaria infection.

Results

A total of 2326 febrile patients (mean age, 20.2 years) were screened for malaria. The presence of malaria parasites was detected by RDT and microscopy in 53.0% and 49.3% of febrile patients, respectively, and was confirmed by PCR in 59.7% (45 missing data). Of 1361 PCR-positive samples, 1205 (88.5%) were P. falciparum, 47 (3.5%) P. vivax, and 99 (7.3%) P. falciparum-P. vivax mixed infection. Malaria transmission occurred mostly during and shortly after the rainy season. The annual rainfall was relatively low in 2016 (267 mm) and 2017 (274 mm), compared to 2015 (448 mm), and coincided with a decline in malaria prevalence in 2016–2017. Although 71.8% of febrile patients reported to possess at least one bed net in the household in our questionnaire, its reported use was not protective against malaria infection (odds ratio: 1.1, 95% CI: 0.91–1.32).

Conclusions

Our study confirmed that P. falciparum is the dominant species in the sahelian zone and that malaria transmission is seasonal and associated with rainfall in this zone. The application of the current national policy based on rapid and reliable malaria diagnosis, case management with artemisinin-based combination therapy, intermittent preventive treatment for pregnant women, distribution and use of long-lasting insecticide impregnated bed nets, and the planned introduction of seasonal malaria chemoprevention for all children under 6 years old is expected to sustainably reduce malaria transmission in this zone.

A Roadmap for the Development of Ivermectin as a Complementary Malaria Vector Control Tool

In the context of stalling progress against malaria, resistance of mosquitoes to insecticides, and residual transmission, mass drug administration (MDA) of ivermectin, an endectocide used for neglected tropical diseases (NTDs), has emerged as a promising complementary vector control method. Ivermectin reduces the life span of Anopheles mosquitoes that feed on treated humans and/or livestock, potentially decreasing malaria parasite transmission when administered at the community level. Following the publication by WHO of the preferred product characteristics for endectocides as vector control tools, this roadmap provides a comprehensive view of processes needed to make ivermectin available as a vector control tool by 2024 with a completely novel mechanism of action. The roadmap covers various aspects, which include 1) the definition of optimal dosage/regimens for ivermectin MDA in both humans and livestock, 2) the risk of resistance to the drug and environmental impact, 3) ethical issues, 4) political and community engagement, 5) translation of evidence into policy, and 6) operational aspects of large-scale deployment of the drug, all in the context of a drug given as a prevention tool acting at the community level. The roadmap reflects the insights of a multidisciplinary group of global health experts who worked together to elucidate the path to inclusion of ivermectin in the toolbox against malaria, to address residual transmission, counteract insecticide resistance, and contribute to the end of this deadly disease.

"Spatial heterogeneity of environmental risk in randomized prevention trials: consequences and modeling"

Background

In the context of environmentally influenced communicable diseases, proximity to environmental sources results in spatial heterogeneity of risk, which is sometimes difficult to measure in the field. Most prevention trials use randomization to achieve comparability between groups, thus failing to account for heterogeneity.

This study aimed to determine under what conditions spatial heterogeneity biases the results of randomized prevention trials, and to compare different approaches to modeling this heterogeneity.

Methods

Using the example of a malaria prevention trial, simulations were performed to quantify the impact of spatial heterogeneity and to compare different models.

Simulated scenarios combined variation in baseline risk, a continuous protective factor (age), a non-related factor (sex), and a binary protective factor (preventive treatment). Simulated spatial heterogeneity scenarios combined variation in breeding site density and effect, location, and population density.

The performances of the following five statistical models were assessed: a non-spatial Cox Proportional Hazard (Cox-PH) model and four models accounting for spatial heterogeneity—i.e., a Data-Generating Model, a Generalized Additive Model (GAM), and two Stochastic Partial Differential Equation (SPDE) models, one modeling survival time and the other the number of events. Using a Bayesian approach, we estimated the SPDE models with an Integrated Nested Laplace Approximation algorithm.

For each factor (age, sex, treatment), model performances were assessed by quantifying parameter estimation biases, mean square errors, confidence interval coverage rates (CRs), and significance rates. The four models were applied to data from a malaria transmission blocking vaccine candidate.

Results

The level of baseline risk did not affect our estimates. However, with a high breeding site density and a strong breeding site effect, the Cox-PH and GAM models underestimated the age and treatment effects (but not the sex effect) with a low CR.

When population density was low, the Cox-SPDE model slightly overestimated the effect of related factors (age, treatment). The two SPDE models corrected the impact of spatial heterogeneity, thus providing the best estimates.

Conclusion

Our results show that when spatial heterogeneity is important but not measured, randomization alone cannot achieve comparability between groups. In such cases, prevention trials should model spatial heterogeneity with an adapted method.

Trial registration

The dataset used for the application example was extracted from Vaccine Trial #NCT02334462 (ClinicalTrials.gov registry).

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0759-z) contains supplementary material, which is available to authorized users.