Anti-group B Streptococcus Immunoglobulin Concentration in Maternal Breast Milk Following Vaccination During Pregnancy

Abstract

Group B Streptococcus (GBS) is a leading cause of neonatal morbidity and mortality. The aim of this study was to determine the concentration of Immunoglobulin A (IgA) and Immunoglobulin G (IgG) against the N-terminal domains of Alpha C, Rib, Alp 1 and Alp 2/3 and total Alp-N IgA and IgG of GBS in the breastmilk of women and compare these between women infected and uninfected with Human Immunodeficiency Virus (HIV), following vaccination with a novel anti-GBS vaccine in pregnancy. Maternal and perinatal outcomes in the first three months of life were investigated. Breastmilk samples were collected from 18 women at Chris Hani Baragwanath Academic Hospital and Rahima Moosa Mother and Child Hospital in Johannesburg, South Africa, within 48 hours, 28 days and 56 days of birth. Demographic and vaccination data were collected. Immunoglobulin concentrations were measured using Enzyme-Linked Immunosorbent Assay. Individual Alp-N IgA concentrations were higher in vaccine than placebo recipients. Concentrations for total Alp-N IgA, Alp 1-N, 2/3N and Alp C-N IgA and total protein were higher in women not infected with HIV than those infected. No difference was observed in total Alp-N IgG between HIV-infected and HIV-uninfected women. Two participants developed hypertension and one, mastitis. Sixteen neonates were born at term and two at post-term. No neonate required resuscitation at birth. There were three neonatal hospital admissions. There were no deaths. The results highlight varying immunogenic responses based on HIV status. Further research evaluating immune response to the vaccine across different populations is needed.