Epidemiology of Acute Lower Respiratory Tract Infection in HIV-Exposed Uninfected Infants

Abstract

BACKGROUND: Increased morbidity and mortality from lower respiratory tract infection (LRTI) has been suggested in HIV-exposed uninfected (HEU) children; however, the contribution of respiratory viruses is unclear. We studied the epidemiology of LRTI hospitalization in HIV-unexposed uninfected (HUU) and HEU infants aged <6 months in South Africa. METHODS: We prospectively enrolled hospitalized infants with LRTI from 4 provinces from 2010 to 2013. Using polymerase chain reaction, nasopharyngeal aspirates were tested for 10 viruses and blood for pneumococcal DNA. Incidence for 2010–2011 was estimated at 1 site with population denominators. RESULTS: We enrolled 3537 children aged <6 months. HIV infection and exposure status were determined for 2507 (71%), of whom 211 (8%) were HIV infected, 850 (34%) were HEU, and 1446 (58%) were HUU. The annual incidence of LRTI was elevated in HEU (incidence rate ratio [IRR] 1.4; 95% confidence interval [CI] 1.3–1.5) and HIV infected (IRR 3.8; 95% CI 3.3–4.5), compared with HUU infants. Relative incidence estimates were greater in HEU than HUU, for respiratory syncytial virus (RSV; IRR 1.4; 95% CI 1.3–1.6) and human metapneumovirus–associated (IRR 1.4; 95% CI 1.1–2.0) LRTI, with a similar trend observed for influenza (IRR 1.2; 95% CI 0.8–1.8). HEU infants overall, and those with RSV-associated LRTI had greater odds (odds ratio 2.1, 95% CI 1.1–3.8, and 12.2, 95% CI 1.7–infinity, respectively) of death than HUU. CONCLUSIONS: HEU infants were more likely to be hospitalized and to die in-hospital than HUU, including specifically due to RSV. This group should be considered a high-risk group for LRTI.