title: Antibody responses to vaccination among South African HIV-exposed and unexposed uninfected infants during the first 2 years of life.
abstract: HIV-exposed but uninfected (HEU) infants born to HIV-infected mothers from areas in the world with a high burden of infectious disease suffer higher infectious morbidity and mortality than their HIV unexposed uninfected (HUU) peers. Vaccination provides protection from infection. The possibility exists that altered response to vaccination contributes to the higher rate of infection in HEU than in HUU infants. While short-term, cross-sectional studies support this notion, it is unclear whether or not HEU infants develop long-term protective immune responses following the WHO extended program on immunization (EPI). Vaccine-specific antibody responses were compared between HEU and HUU infants from 2 weeks until 2 years of age in a longitudinal South African cohort. Total IgG and antibodies specific for Bordetella pertussis, Haemophilus influenzae type b (Hib), tetanus toxoid, hepatitis B virus (HepB), and measles virus were measured at multiple time points throughout the first 2 years of life. Prevaccine antibodies (maternal antibodies passively acquired) specific for tetanus were lower in HEU than in HUU infants, while prevaccine antibodies to HepB were higher in HEU than in HUU infants. Both groups responded similarly to tetanus, Hib, and HepB vaccination. HEU demonstrated stronger pertussis vaccine responses, developing protective titers 1 year earlier than HUU patients, and maintained higher anti-tetanus titers at 24 months of age. Vaccine-induced antibodies to measles virus were similar in both groups at all time points. Our results suggest that the current EPI vaccination program as practiced in South Africa leads to the development of vaccine-specific antibody responses that are equivalent in HEU and HUU infants. However, our data also suggest that a large fraction of both HEU and HUU South African infants have antibody titers for several infectious threats that remain below the level of protection for much of their first 2 years of life.
authors.affiliation: Division of Infectious & Immunological Diseases and Centre for Understanding and Preventing Infections in Children, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Reikie
authors.forename: Shalena
authors.initials: S
authors.lastname: Naidoo
authors.forename: Candice E
authors.initials: CE
authors.lastname: Ruck
authors.forename: Amy L
authors.initials: AL
authors.lastname: Slogrove
authors.forename: Corena
authors.initials: C
authors.lastname: de Beer
authors.forename: Heleen
authors.initials: H
authors.lastname: la Grange
authors.forename: Rozanne C M
authors.initials: RC
authors.lastname: Adams
authors.forename: Kevin
authors.initials: K
authors.lastname: Ho
authors.forename: Kinga
authors.initials: K
authors.lastname: Smolen
authors.forename: David P
authors.initials: DP
authors.lastname: Speert
authors.forename: Mark F
authors.initials: MF
authors.lastname: Cotton
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Preiser
authors.forename: Monika
authors.initials: M
authors.lastname: Esser
authors.forename: Tobias R
authors.initials: TR
authors.lastname: Kollmann
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013019:South Africa; D014612:Vaccines / Q000008:administration & dosage* / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D007074:Immunoglobulin G; D014612:Vaccines