• The duration of chemoprophylaxis against malaria after treatment with artesunate-amodiaquine and artemether-lumefantrine and the effects of pfmdr1 86Y and pfcrt 76T: a meta-analysis of individual patient data

      Bretscher, M; Dahal, P; Griffin, J; Bassat, Q; Baudin, E; D'Alessandro, U; Djimde, AA; Dorsey, G; Espié, E; Fofana, B; et al. (BioMed Central, 2020-02-25)
      BACKGROUND: The majority of Plasmodium falciparum malaria cases in Africa are treated with the artemisinin combination therapies artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), with amodiaquine being also widely used as part of seasonal malaria chemoprevention programs combined with sulfadoxine-pyrimethamine. While artemisinin derivatives have a short half-life, lumefantrine and amodiaquine may give rise to differing durations of post-treatment prophylaxis, an important additional benefit to patients in higher transmission areas. METHODS: We analyzed individual patient data from 8 clinical trials of AL versus AS-AQ in 12 sites in Africa (n = 4214 individuals). The time to PCR-confirmed reinfection after treatment was used to estimate the duration of post-treatment protection, accounting for variation in transmission intensity between settings using hidden semi-Markov models. Accelerated failure-time models were used to identify potential effects of covariates on the time to reinfection. The estimated duration of chemoprophylaxis was then used in a mathematical model of malaria transmission to determine the potential public health impact of each drug when used for first-line treatment. RESULTS: We estimated a mean duration of post-treatment protection of 13.0 days (95% CI 10.7-15.7) for AL and 15.2 days (95% CI 12.8-18.4) for AS-AQ overall. However, the duration varied significantly between trial sites, from 8.7-18.6 days for AL and 10.2-18.7 days for AS-AQ. Significant predictors of time to reinfection in multivariable models were transmission intensity, age, drug, and parasite genotype. Where wild type pfmdr1 and pfcrt parasite genotypes predominated (<=20% 86Y and 76T mutants, respectively), AS-AQ provided ~ 2-fold longer protection than AL. Conversely, at a higher prevalence of 86Y and 76T mutant parasites (> 80%), AL provided up to 1.5-fold longer protection than AS-AQ. Our simulations found that these differences in the duration of protection could alter population-level clinical incidence of malaria by up to 14% in under-5-year-old children when the drugs were used as first-line treatments in areas with high, seasonal transmission. CONCLUSION: Choosing a first-line treatment which provides optimal post-treatment prophylaxis given the local prevalence of resistance-associated markers could make a significant contribution to reducing malaria morbidity.
    • Efficacy of Artemether-Lumefantrine in Relation to Drug Exposure in Children With and Without Severe Acute Malnutrition: an Open Comparative Intervention Study in Mali and Niger

      Denoeud-Ndam, L; Dicko, A; Baudin, E; Guindo, O; Grandesso, F; Diawara, H; Sissoko, S; Sanogo, K; Traoré, S; Keita, S; et al. (BioMed Central, 2016-10-24)
      Severe acute malnutrition (SAM) affects almost all organs and has been associated with reduced intestinal absorption of medicines. However, very limited information is available on the pharmacokinetic properties of antimalarial drugs in this vulnerable population. We assessed artemether-lumefantrine (AL) clinical efficacy in children with SAM compared to those without.
    • Impact and Lessons Learned from Mass Drug Administrations of Malaria Chemoprevention during the Ebola Outbreak in Monrovia, Liberia, 2014

      Kuehne, A; Tiffany, A; Lasry, E; Janssens, M; Besse, C; Okonta, C; Larbi, K; Pah, AC; Danis, K; Porten, K (Public Library of Science, 2016-08-31)
      In October 2014, during the Ebola outbreak in Liberia healthcare services were limited while malaria transmission continued. Médecins Sans Frontières (MSF) implemented a mass drug administration (MDA) of malaria chemoprevention (CP) in Monrovia to reduce malaria-associated morbidity. In order to inform future interventions, we described the scale of the MDA, evaluated its acceptance and estimated the effectiveness.
    • Intermittent Preventive Treatment for Malaria Among Children in a Refugee Camp in Northern Uganda: Lessons Learned

      Coldiron, M; Lasry, E; Bouhenia, M; Das, D; Okui, P; Nyehangane, D; Mwanga, J; Langendorf, C; Elder, G; Salumu, L; et al. (BioMed Central, 2017-05-23)
      Northern Uganda hosts a large population of refugees from South Sudan, and malaria is one of the major health problems in the area. In 2015, intermittent preventive treatment for malaria (IPTc) was implemented in two refugee camps among children aged 6 months to 14 years. Three distributions of dihydroartemisinin-piperaquine (DP) were conducted at 8-week intervals. The first dose was directly administered at IPTc distribution sites and the second and third doses were given to caregivers to administer at home. A multi-faceted evaluation was implemented, including coverage surveys, malaria prevalence surveys, reinforced surveillance, and pharmacovigilance. Programme coverage exceeded 90% during all three distributions with a total of 40,611 participants. Compared to same period during the previous year (only available data), the incidence of malaria in the target populations was reduced (IRR 0.73, 95% CI 0.69-0.77 among children under 5 years old; IRR 0.70, 95% CI 0.67-0.72 among children aged 5-14 years). Among those not targeted for intervention, the incidence between the 2 years increased (IRR 1.49, 95% CI 1.42-1.56). Cross-sectional surveys showed a prevalence of parasitaemia (microscopy or PCR) of 12.9-16.4% (95% CI 12.6-19.3) during the intervention, with the highest prevalence among children aged 5-14 years, but with a large increase 8 weeks after the final distribution. A total of 57 adverse events were reported during the intervention period, including one severe adverse event (death from varicella). Adverse events were of mild to moderate severity, and were mainly dermatologic and gastrointestinal. This is the first documentation of an IPTc programme in a refugee camp. The positive impact of DP on the incidence of malaria, together with its favourable safety profile, should lead to further use of IPTc in similar settings. Expanding coverage groups and decreasing intervals between distributions might provide more benefit, but would need to be balanced with the operational implications of a broader, more frequent distribution schedule.
    • Malaria in pregnancy: a call for a safe, efficient, and patient-centred approach to first-trimester treatment.

      Rao, VB; Jensen, TO; Jimenez, BC; Robays, J; Lasry, E; Sterk, E; de Smet, M (Elsevier, 2018-06-06)
    • Needs and Challenges in Modelling Malaria for Emergency Contexts

      Boëte, C; Guardiola, M; Lasry, E; Burza, S; Moriana, S; Robertson, W (Elsevier, 2020-05-29)
      While modelling is an essential component for an understanding of the epidemiology of malaria, and for designing better control measures, it rarely considers the particular contexts encountered in emergency settings. By linking these situations with the transmission parameters our aim is to correct this bias and call for a better collaboration between relief actors.
    • Seasonal Malaria Chemoprevention with Sulphadoxine-Pyrimethamine and Amodiaquine Selects Pfdhfr-dhps Quintuple Mutant Genotype in Mali

      Maiga, H; Lasry, E; Diarra, M; Sagara, I; Bamadio, A; Traore, A; Coumare, S; Bahonan, S; Sangare, B; Dicko, Y; et al. (Public Library of Science, 2016-09-23)
      Seasonal malaria chemoprevention (SMC) with sulphadoxine-pyrimethamine (SP) plus amodiaquine (AQ) is being scaled up in Sahelian countries of West Africa. However, the potential development of Plasmodium falciparum resistance to the respective component drugs is a major concern.
    • Single low-dose primaquine for blocking transmission of Plasmodium falciparum malaria - a proposed model-derived age-based regimen for sub-Saharan Africa

      Taylor, WR; Naw, HK; Maitland, K; Williams, TN; Kapulu, M; D'Alessandro, U; Berkley, JA; Bejon, P; Okebe, J; Achan, J; et al. (BioMed Central, 2018-01-18)
      In 2012, the World Health Organization recommended blocking the transmission of Plasmodium falciparum with single low-dose primaquine (SLDPQ, target dose 0.25 mg base/kg body weight), without testing for glucose-6-phosphate dehydrogenase deficiency (G6PDd), when treating patients with uncomplicated falciparum malaria. We sought to develop an age-based SLDPQ regimen that would be suitable for sub-Saharan Africa.
    • Two-Year Scale-Up of Seasonal Malaria Chemoprevention Reduced Malaria Morbidity among Children in the Health District of Koutiala, Mali.

      Maiga, H; Gaudart, J; Sagara, I; Diarra, M; Bamadio, A; Djimde, M; Coumare, S; Sangare, B; Dicko, Y; Tembely, A; et al. (MDPI, 2020-09-11)
      Background: Previous controlled studies demonstrated seasonal malaria chemoprevention (SMC) reduces malaria morbidity by >80% in children aged 3-59 months. Here, we assessed malaria morbidity after large-scale SMC implementation during a pilot campaign in the health district of Koutiala, Mali. Methods: Starting in August 2012, children received three rounds of SMC with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ). From July 2013 onward, children received four rounds of SMC. Prevalence of malaria infection, clinical malaria and anemia were assessed during two cross-sectional surveys conducted in August 2012 and June 2014. Investigations involved 20 randomly selected clusters in 2012 against 10 clusters in 2014. Results: Overall, 662 children were included in 2012, and 670 in 2014. Children in 2014 versus those surveyed in 2012 showed reduced proportions of malaria infection (12.4% in 2014 versus 28.7% in 2012 (p = 0.001)), clinical malaria (0.3% versus 4.2%, respectively (p < 0.001)), and anemia (50.1% versus 67.4%, respectively (p = 0.001)). A propensity score approach that accounts for environmental differences showed that SMC conveyed a significant protective effect against malaria infection (IR = 0.01, 95% CI (0.0001; 0.09), clinical malaria (OR = 0.25, 95% CI (0.06; 0.85)), and hemoglobin concentration (β = 1.3, 95% CI (0.69; 1.96)) in 2012 and 2014, respectively. Conclusion: SMC significantly reduced frequency of malaria infection, clinical malaria and anemia two years after SMC scale-up in Koutiala.