Vesikari T et al. – 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.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.
- 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.