Immunologic and Virologic Factors Associated With Hospitalization in Human Immunodeficiency Virus-Exposed, Uninfected Infants in the United States

Background. Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) infants experience higher rates of morbidity and mortality than HIV-unexposed, uninfected (HUU) infants. Few studies have examined whether particular infections and/or immune responses are associated with hospitalization among HEU infants born in the United States. Methods. We evaluated a subset of HEU infants enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group P1025 and/or Pediatric HIV/AIDS Cohort Study Surveillance Monitoring for ART Toxicities studies. We determined seroconversion to 6 respiratory viruses and measured antibody concentrations to 9 vaccine antigens using quantitative ELISA or electrochemiluminescence. Multivariable modified Poisson regression models were fit to evaluate associations of seroconversion to each respiratory virus/family and antibody concentrations to vaccine antigens with risk of hospitalization in the first year of life. Antibody concentrations to vaccine antigens were compared between HEU infants and HUU infants from a single site using multivariable linear regression models. Results. Among 556 HEU infants, seroconversion to respiratory syncytial virus (RSV) and parainfluenza was associated with hospitalization (adjusted risk ratio, 1.95 [95% CI, 1.21-3.15] and 2.30 [1.42-3.73], respectively). Antibody concentrations to tetanus toxoid, pertussis, and pneumococcal vaccine antigens were higher among 525 HEU compared with 100 HUU infants. No associations were observed between antibody concentrations with any vaccine and hospitalization among HEU infants. Conclusions. RSV and parainfluenza contribute to hospitalization among HEU infants in the first year of life. HEU infants demonstrate robust antibody responses to vaccine antigens; therefore, humoral immune defects likely do not explain the increased susceptibility to infection observed in this population.