Prolonged Breastfeeding and the Risk of Plasmodium vivax Infection and Clinical Malaria in Early Childhood: A Birth Cohort Study

Abstract

Background: Relatively few Amazonian infants have clinical malaria diagnosed, treated and notified before their first birthday, either because they are little exposed to an infection or remain asymptomatic once infected. Here we measure the proportion of children who have experienced Plasmodium vivax infection and malaria by 2 years of age in the main transmission hotspot of Amazonian Brazil. Methods: We measured IgG antibodies to 3 blood-stage P. vivax antigens at the 1-and 2-year follow-up assessment of 435 participants in a population-based birth cohort. Children's malaria case notifications were retrieved from the electronic database of the Ministry of Health. We used multiple Poisson regression models to identify predictors of serologically proven P. vivax infection and clinical vivax malaria during the first 2 years of life. Results: Overall, 23 [5.3%; 95% confidence interval (CI): 3.5-7.8%) children had antibodies to ≥2 antigens detected during at least one follow-up assessment, consistent with past P. vivax infection(s). Fifteen (3.4%; 95% CI: 2.1-5.6%) children had clinical vivax episodes notified during the first 2 years of life; 7 of them were seronegative. We estimate that half of the infections remained unnotified. Children born to women who experienced P. vivax infection during pregnancy were more likely to be infected and develop clinical vivax malaria, while those breast-fed for ≥12 months had their risk of being P. vivax-seropositive (which we take as evidence of blood-stage P. vivax infection during the first 2 years of life) decreased by 79.8% (95% CI: 69.3-86.7%). Conclusion:P. vivax infections in early childhood are underreported in the Amazon, are associated with anemia at 2 years of age, and appear to be partially prevented by prolonged breastfeeding.

Prevalence and correlates of childhood anemia in the MINA-Brazil birth cohort study

“…Among children with persistent anemia from one to two years, our results reinforce the importance of promoting continued breastfeeding with nutritious complementary diets and adequate treatment of childhood infections such as malaria. In a previous analysis of the MINA-Brazil cohort, children exposed to gestational malaria and breastfed for at least 12 months had a decreased risk for malaria infection during the first two years of life 26 . Breastfeeding protects young children from infections with the passive transfer of immunoglobulins and other bioactive substances 26 , which could be one possible explanation for the association of prolonged breastfeeding and decreased risk for anemia at age five observed in this study.…”

“…Entre as crianças com anemia persistente entre o primeiro e o segundo ano de vida, nossos resultados reforçam a importância da promoção do aleitamento materno contínuo com dietas complementares nutritivas e tratamento adequado de infecções infantis, como a malária. Em uma análise anterior da coorte MINA-Brasil, crianças expostas à malária gestacional e amamentadas por pelo menos 12 meses tiveram um risco reduzido de infecção por malária durante os dois primeiros anos de vida 26 . O aleitamento materno protege as crianças pequenas de infecções por transferência passiva de imunoglobulinas e outras substâncias bioativas 26 , o que poderia ser uma possível explicação para a associação de aleitamento materno prolongado e diminuição do risco de anemia aos cinco anos de idade, observada neste estudo.…”

“…Em uma análise anterior da coorte MINA-Brasil, crianças expostas à malária gestacional e amamentadas por pelo menos 12 meses tiveram um risco reduzido de infecção por malária durante os dois primeiros anos de vida 26 . O aleitamento materno protege as crianças pequenas de infecções por transferência passiva de imunoglobulinas e outras substâncias bioativas 26 , o que poderia ser uma possível explicação para a associação de aleitamento materno prolongado e diminuição do risco de anemia aos cinco anos de idade, observada neste estudo.…”

Prevalence and predictors of breastfeeding in the MINA-Brazil cohort

“…The protective effect of breastfeeding against infectious diseases is well documented in the literature 2 . A previous study on the MINA-Brazil cohort showed that children who were born to women that had gestational malaria and were breastfed for at least 12 months presented a decreased risk for malaria infection during the first 2 years of life 21 . Respiratory and gastrointestinal illnesses have been reported in BF infants from low-income populations, which are exposed to precarious environments and have limited access to healthcare 8 , 22 .…”

“…O efeito protetor do aleitamento materno contra doenças infecciosas está bem documentado na literatura 2 . Um estudo anterior com dados da coorte MINA-Brasil mostrou que as crianças nascidas de mulheres com malária gestacional, amamentadas por pelo menos 12 meses, apresentaram risco reduzido de infecção por malária nos primeiros 2 anos de vida 21 . Doenças respiratórias e gastrointestinais têm sido relatadas em lactentes em AM em populações de baixa renda, expostos a ambientes precários e com acesso limitado aos cuidados de saúde 8 , 22 .…”