Vivax Malaria: A Major Cause of Morbidity in Early Infancy

Background. In areas where malaria is endemic, infants aged <3 months appear to be relatively protected from symptomatic and severe Plasmodium falciparum malaria, but less is known about the effect of Plasmodium vivax infection in this age group. Methods. To define malaria morbidity in the first year of life in an area where both multidrug-resistant P. falciparum and P. vivax are highly prevalent, data were gathered on all infants attending a referral hospital in Papua, Indonesia, using systematic data forms and hospital computerized records. Additional clinical and laboratory data were prospectively collected from inpatients aged <3 months. Results. From April 2004 through April 2008, 4976 infants were admitted to the hospital, of whom 1560 (31%) had malaria, with infection equally attributable to P. falciparum and P. vivax. The case-fatality rate was similar for inpatients with P. falciparum malaria (13 [2.2%] of 599 inpatients died) and P. vivax malaria (6 [1.0%] of 603 died; P = .161), whereas severe malarial anemia was more prevalent among those with P. vivax malaria (193 [32%] of 605 vs. 144 [24%] of 601; P = .025). Of the 187 infants aged <3 months, 102 (56%) had P. vivax malaria, and 55 (30%) had P. falciparum malaria. In these young infants, infection with P. vivax was associated with a greater risk of severe anemia (odds ratio, 2.4; 95% confidence interval, 1.03-5.91; P = .041) and severe thrombocytopenia (odds ratio, 3.3; 95% confidence interval, 1.07-10.6; P = .36) compared with those who have P. falciparum infection. Conclusions. P. vivax malaria is a major cause of morbidity in early infancy. Preventive strategies, early diagnosis, and prompt treatment should be initiated in the perinatal period.