Background: Rotavirus is the main cause of severe gastroenteritis and diarrhea in infants and young children less than 5 years of age. Potential impact of breast-feeding on the efficacy and immunogenicity of human rotavirus G1P vaccine was examined in this exploratory analysis.
Methods: Healthy infants (N = 3994) aged 6–14 weeks who received 2 doses of human rotavirus vaccine/placebo according to a 0–1 or 0–2 month schedule were followed for rotavirus gastroenteritis during 2 epidemic seasons. Rotavirus IgA seroconversion rate (anti-IgA antibody concentration ≥20 mIU/mL) and geometric mean concentrations were measured prevaccination and 1–2 months post-dose 2. Vaccine efficacy against any and severe rotavirus gastroenteritis was analyzed according to the infants being breast-fed or exclusively formula-fed at the time of vaccination.
Results: Antirotavirus IgA seroconversion rate was 85.5% (95% confidence interval [CI]: 82.4–88.3) in breast-fed and 89.2% (95% CI: 84.2–93) in exclusively formula-fed infants; geometric mean concentrations in the respective groups were 185.8 U/mL (95% CI: 161.4–213.9) and 231.5 U/mL (95% CI: 185.9–288.2). Vaccine efficacy was equally high in breast-fed and exclusively formula-fed children in the first season but fell in breast-fed infants in the second rotavirus season. During the combined 2-year efficacy follow-up period, vaccine efficacy against any rotavirus gastroenteritis was 76.2% (95% CI: 68.7–82.1) and 89.8% (95% CI: 77.6–95.9) and against severe rotavirus gastroenteritis 88.4% (95% CI: 81.6–93) and 98.1% (95% CI: 88.2–100) in the breast-fed and exclusively formula-fed infants, respectively.
Conclusions: The difference in immunogenicity of human rotavirus vaccine in breast-fed and exclusively formula-fed infants was small. Vaccine efficacy was equally high in breast-fed and exclusively formula-fed children in the first season. Breast-feeding seemed to reduce slightly the efficacy in the second season.
*Vaccine Research Center, Medical School, University of Tampere, Tampere, Finland
†Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
‡Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany
§Hospital de Móstoles, Madrid, Spain
¶Medical Facility, St Maur des Fossés, France
║Sanofi Pasteur, Swiftwater, PA
**GlaxoSmithKline Biologicals, Rixensart, Belgium
Accepted for publication December 28, 2011.
This study was funded by GlaxoSmithKline Biologicals.
V.S. received investigator fees from GlaxoSmithKline. T.V. is on the advisory boards of GlaxoSmithKline, Sanofi-Pasteur-MSD, Novartis and MedImmune and has received consultation and lecture fees from the same. R.P. is a consultant and member of the advisory boards of GlaxoSmithKline and MSD, honoraria. J.C.T. received investigator fees from GlaxoSmithKline. R.C. received payment for lectures and was part of speaker’s bureau for GlaxoSmithKline, Wyeth-Pfizer, Sanofi-Pasteur-MSD and Novartis. A.B. was an employee of GlaxoSmithKline Biologicals at the time of the study and is now an employee of Sanofi Pasteur. S.D. is an employee of GlaxoSmithKline. H.H.H. is an employee of GlaxoSmithKline and own shares in GlaxoSmithKline. Rotarix is the trademark of GlaxoSmithKline group of companies. RotaClone is the trademark of Meridian Bioscience group of companies. The authors have no other funding or conflicts of interest to disclose.
Address for correspondence: Timo Vesikari, MD, PhD, Vaccine Research Center, University of Tampere Medical School, FIN-33014 Tampere, Finland. E-mail: email@example.com.