Background: Malariometric information is needed to decide how to introduce malaria vaccines and evaluate their impact in sub-Saharan African countries. Methods: This cross-sectional study (NCT01954264) was conducted between October and November, 2013, corresponding to the high malaria transmission season, in four sites with Health and Demographic Surveillance Systems (DSS) [two sites with moderate-to-high malaria endemicity in Burkina Faso (Nouna and Sapone) and two sites with low malaria endemicity in Senegal (Keur Soce and Niakhar)]. Children (N = 2421) were randomly selected from the DSS lists of the study sites and were stratified into two age groups (6 months-4 years and 5-9 years). A blood sample was collected from each child to evalu...