The Plus Project will assess the impact, operational feasibility, efficacy, effectiveness, and cost-effectiveness of PMC. Specifically, the impact evaluation will involve monitoring a passive cohort of all children in the study area reporting all doses of SP received and the number of confirmed cases of malaria and anaemia, as well as a prospective active cohort of children who will have seven home visits over an 18-month period. The total number of participants is expected to be approximately 2,080 children in the areas served by 35 health centres in Cameroon. The results of this study will allow direct evaluation of the protective efficacy of PMC on malaria incidence, severe anaemia, and malaria mortality.

Despite impressive progress in recent years, malaria continues to impose a heavy morbidity and mortality burden. Ninety-five percent of the estimated 247 million malaria cases and 619,000 deaths worldwide in 2021 occurred in the World Health Organization (WHO) Africa Region [1]. The expansion of SP-IPTi to include children up to two years of age and additional entry points, referred to now as PMC, offers the potential to increase the impact of the intervention by delivering more protective doses of SP to an age group with a higher malaria burden. However, to support the development of national policies and international guidelines on the adoption and implementation of PMC at scale, more evidence is needed on where, when, how and under what circumstances PMC can be effective, cost-effective, acceptable, equitable and feasible.

The aim of the impact evaluation is to inform decision-making by policy makers and programme managers involved in national malaria control programmes by evaluating the protective efficacy of PMC with eight doses versus five doses as standard of care in Cameroon. The design is a multi-site quantitative study of the implementation of PMC in Cameroon. The health districts of Soa and Mbankomo were identified as the intervention and control districts, respectively, based on population size, number of Extended Programme of Immunisation (EPI) facilities, malaria incidence, EPI coverage and availability of an appropriate control population receiving standard care.

All children up to 36 months of age with parental consent will be recruited into a passive cohort. The investigators will also extract data on malaria and anaemia cases among children receiving PMC from health facility records.

The investigators will form and follow an active arm of the cohort in which a randomly selected subset of children in the passive cohort will be visited every three months during the study period in their homes to obtain detailed information, including details of the household, malaria risk factors, history of malaria and anaemia, health-seeking behaviour, and past EPI vaccinations. Blood will be collected for microscopy measures of parasitaemia, anaemia diagnosis by haemoglobin levels, and retrospective analysis of malaria infection (not for clinical management) by polymerase chain reaction methods. Rapid diagnostic tests will be used amongst symptomatic children to identify cases. First line antimalarial treatment will be provided to all confirmed cases. Children will be screened for malnutrition by measuring their mid-upper arm circumference (MUAC). If they are determined to have either moderate (MAM) or severe acute malnutrition (SAM), treatment will consist of standard of care which can include referral to the nearest health facility with clinical management capacity or treatment on site.

Inclusion Criteria:

• Reside in Soa (intervention) or Mbankomo (control) health districts.
• Agree to take part in the census.
• Aged 6-9 months at the time of enrolment.

Exclusion Criteria:

• Parent/caregiver refused to participate in the cohort.
• Parent/caregiver did not give informed consent.

Children up to 9 months of age in Soa and Mbankomo health districts of Cameroon.