Malarial Morbidity and Postnatal HIV Infection in Breastfeeding HIV-exposed Infants

Background: For at-risk HIV-negative individuals, whether malarial morbidity increases the likelihood of HIV infection when exposed is unknown. Hence, we investigate the malaria-associated risk of postnatal HIV infection in 1804 breastfeeding infants of HIV-positive women from Dar es Salaam, Tanzania.
Methods: Six-week-old HIV-negative infants were followed until breastfeeding cessation or postnatal HIV infection. HIV-1 status was determined by a DNA PCR test. Malarial morbidity was diagnosed by physicians using a combination of clinical symptoms and laboratory tests. For analytic purposes, malaria was distinguished by diagnostic specificity as: (1) clinical; (2) probable, where laboratory testing is requested for parasitemia; and (3) blood smear-confirmed. Hazard ratios (HR) and 95% confidence intervals (CI) for the risk of HIV infection were estimated from multivariate Cox regression models.
Results: Mean follow-up duration was 6.2 months (standard deviation=2.4 months), during which 91 new HIV infections developed and clinical malaria was diagnosed in 594(32.3%) children, including 283 (15.5%) probable and 80(4.4%) confirmed malaria episodes. Infants ever diagnosed with clinical and probable malaria were at 73% (95%CI:1.11 - 2.69) and 100% (95%CI:1.17-3.42) higher risk of postnatal HIV infection, respectively. This risk increased by 39% (95%CI: 1.08-1.80) and 59% (95%CI: 1.00-2.32), respectively, per episode increment in clinical and probable malarial; however, confirmed malaria was not significantly associated with HIV incidence (HR=2.09; 95%CI: 0.74 - 5.91).
Conclusion: We found positive associations between child malarial infection and postnatal HIV infection among breastfeeding HIV-negative children of HIV-positive women. These findings suggest that malaria prevention in such infants may decrease the risk of HIV mother-to-child-transmission. However, specific future studies using laboratory-confirmed malaria in HIV-negative but HIV at risk populations are needed to substantiate these findings.