Plasmodium falciparum infection and disease in infancy associated with increased risk of malaria and anaemia in childhood

Abstract

Abstract Background Infants under 6 months of age are often excluded from malaria surveillance and observational studies. The impact of malaria during early infancy on health later in childhood remains unknown. Methods Infants from two birth cohorts in Malawi were monitored at quarterly intervals and whenever they were ill from birth through 24 months for Plasmodium falciparum infections and clinical malaria. Poisson regression and linear mixed effects models measured the effect of exposure to malaria in infancy on subsequent malaria incidence, weight-for-age z-scores (WAZ), and haemoglobin concentrations after 6 months. Results Infants with at least one P. falciparum infection during their first 6 months had increased incidence ratio (IRR) of P. falciparum infection (IRR = 1.27, 95% CI, 1.06–1.52) and clinical malaria (IRR = 2.37, 95% CI, 2.02–2.80) compared to infants without infection. Infants with clinical malaria had increased risk of P. falciparum infection incidence between 6 and 24 months (IRR = 1.64, 95% CI, 1.38–1.94) and clinical malaria (IRR = 1.85, 95% CI, 1.48–2.32). Exposure to malaria was associated with lower WAZ over time (p = 0.02) and lower haemoglobin levels than unexposed infants at every time interval (p = 0.02). Conclusions Infants experiencing malaria infection or clinical malaria are at increased risk of subsequent infection and disease, have poorer growth, and lower haemoglobin concentrations.