Analysis of Anti-malarial Immunity Development in Early Life in a Prospective Birth Cohort in Agogo, Ghana

Malaria during pregnancy poses substantial risks for the mother and her foetus. Due to the risk of malaria during early childhood, the study addresses the high malaria morbidity and mortality in young children. Though recognised as a public health issue, it has still not been well understood how clinical immunity against malaria parasites develops, which parasite and host factors play a role in infection susceptibility, and why some infections proceed to develop severe complications while others resolve after a mild disease.

In order to identify interactions between parasite and host, a longitudinal study is performed starting with the recruitment of pregnant women. The study is conducted in Agogo in Ghana, an area with high malaria endemicity. The study design allows to analyse the neonatal immune status at birth, after potential in-utero exposure, and follows the development of immunity over the first 36 months of life. The current paradigm is that time points and frequency of infection as well as the type of variant surface antigen expressed have an impact on the cellular and humoral immune response to malaria, the development of clinical immunity, as well as the risk for future complications.

Starting point of the study is the antenatal care visit of mothers at Agogo Presbyterian Hospital (APH) during pregnancy. During recruitment, the mother will be asked to read and sign an informed consent form approved by the local ethical committee. After consent has been obtained from the mother, biological samples are taken, and a case report form is filled. An identification card with a unique code number is handed out. The first follow-up visit occurs at the birth of the child. At this time point, samples are taken from the mothers and the child. Mothers/primary caregivers are invited to observe the EPI visits offered at their nearest health post for further follow-ups. In the first year after birth, the EPI schedule includes visits at six weeks, ten weeks, 14 weeks, six months, and nine months. During these visits, questionnaires are completed and stool samples are taken. In the first six weeks after birth, the household is visited to complete a household questionnaire including housing characteristics and household assets. Additionally, a women's questionnaire is administered, which collects demographic and socioeconomic background characteristics as well as health and related behavioural data. At 12, 18, 24, and 36 months after birth, mothers/primary caregivers are encouraged to bring their children to the study hospital (APH) for a medical check-up. For the period of 36 months after birth, mothers/primary caregivers are strongly encouraged to visit the study hospital (APH) every time the child experiences a febrile illness or a history of fever in the last week during the observation period.