Cases of clinical malaria (secondary case definition) averted during an 18-mo follow-up period in infants 6–12 wk of age at enrollment, by study site, ordered by increasing malaria incidence at each site (intention-to-treat population).

<p>Clinical malaria secondary case definition: illness in a child brought to a study facility with a measured temperature of ≥37.5°C or reported fever within the last 24 h and <i>P. falciparum</i> asexual parasitemia at a density of >0 parasites/mm³. This definition was used for this analysis because during routine clinical practice these children would normally receive a full course of anti-malarial treatment. Study sites are ordered from lowest (Kilifi) to highest (Siaya) incidence of clinical malaria, defined as a measured or reported fever within previous 24 h and parasite density >0 parasites/mm³ (i.e., clinical malaria secondary case definition), measured in control infants 6–12 wk of age at enrollment during 12 mo of follow-up.