Host Immune Dynamics Following Seasonal Malaria Chemoprevention in African Children

The study aims to identify immune features linked to protection against malaria, examining variations by age and sex, and measuring changes in immune responses over time following seasonal malaria chemoprevention (SMC). The primary objectives are:

1. Thorough examination of antibody immune responses in individuals before and after one or more SMC rounds.
2. Thorough examination of both innate and adaptive cellular immune responses in people residing in areas with regular SMC use.

Participants will include children aged 3 to 59 months who have received at least two or three SMC rounds, as well as children aged 5 to 15 years with no prior SMC exposure.

Upon identifying participants, study details will be provided, and written informed consent obtained. Demographic and clinical information will be collected using standard case record forms, including previous SMC uptake and routine malaria control interventions. Information on SMC use will be obtained from SMC cards/existing medical records, detailing the number of cycles received, adherence, and general health condition, including previous diseases and EPI vaccine uptake.

Data Collection:

• Face-to-face interviews by trained research assistants.
• Clinical assessments, including temperature, weight, and mid-upper arm circumference (MUAC).
• Sickle cell status testing at enrolment via samples analyzed at the Molecular Research Laboratory (MOLAB).
• Hemoglobin measurement using a HemoCue analyzer.

Malaria Diagnosis:

• Blood samples collected for malaria diagnosis using rapid diagnostic tests (RDTs) and microscopy.
• RDTs, such as Paracheck Pf, will be performed according to manufacturer instructions, with results available within 15 minutes.
• Participants testing positive for malaria will receive a full course of antimalarial treatment and counselling to visit the nearest health facility if symptoms worsen.

Thick Blood Smears:

• New glass slides labelled with participant ID will be used for thick blood smears.
• Blood smears will be dried and stored in a cool, dust-free environment before transportation to central laboratories.
• Slides will be stained with 2% Giemsa for 30 minutes and evaluated for parasitemia and gametocytes, with densities calculated accordingly.

The study will help understand the immune responses to malaria and the efficacy of SMC in different age groups.