A clinical case of malaria is detected, treated, and reported on relatively few Amazonian newborns before their first birthday. This may be because Amazonian infants are rarely exposed to an infection or because, once infected, they typically show no symptoms of the disease. In this study, researchers investigated the prevalence of Plasmodium vivax infection and malaria in children under the age of 2 years old in the primary malaria transmission hotspot in the Amazonian region of Brazil. At the 1- and 2-year follow-up assessments of 435 individuals in a population-based birth cohort, they assessed IgG antibodies to 3 blood-stage P. vivax antigens. These participants were all born in the same year. The electronic database maintained by the Ministry of Health was searched to retrieve notifications of malaria cases in children. During the first 2 years of a person’s existence, they utilized various Poisson regression models in order to uncover predictors of serologically proved P. vivax infection as well as clinical vivax malaria. In total, 23 (5.3%) of the children, with a 95% CI ranging from 3.5–7.8%, exhibited antibodies to more than or equal to 2 antigens that were found during at least 1 follow-up evaluation, which is consistent with a previous infection with P. vivax (s). During the first 2 years of life, clinical vivax episodes were reported in 15 children (3.4%; 95% CI: 2.1–5.6%); 7 of these infants had negative serologies. According to the best estimates, approximately half of the illnesses went unreported. Those children who were breastfed for more than 12 months had a decreased risk of being P. vivax-seropositive, which researchers take as evidence of blood-stage P. vivax infection during the first 2 years of life. This risk was reduced by 79.8% (95% CI: 69.3–86.7%). Children born to mothers who had P. vivax infection during pregnancy were more likely to be infected and develop clinical vivax malaria. P. vivax infections in early childhood are underreported in the Amazon, are related with anemia at 2 years of age, and appear to be partially avoided by prolonged breastfeeding for infants and young children in the Amazon.

Source: journals.lww.com/pidj/Abstract/2022/10000/Prolonged_Breastfeeding_and_the_Risk_of_Plasmodium.2.aspx