Efficacy and immunogenicity of live-attenuated human rotavirus vaccine in breast-fed and formula-fed European infants.
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[8] 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. timo.vesikari@uta.fi
Timo
T
Vesikari
Roman
R
Prymula
Volker
V
Schuster
Juan-C
JC
Tejedor
Robert
R
Cohen
Alain
A
Bouckenooghe
Silvia
S
Damaso
Htay Htay
HH
Han
D000914:Antibodies, Viral / Q000097:blood*; D001942:Breast Feeding; D002675:Child, Preschool; D005060:Europe; D005260:Female; D005759:Gastroenteritis / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007223:Infant; D041943:Infant Formula / Q000008:administration & dosage*; D008297:Male; D012401:Rotavirus / Q000276:immunology*; D012400:Rotavirus Infections / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use; D012621:Seasons; D016896:Treatment Outcome; D014611:Vaccination
D000914:Antibodies, Viral; D007070:Immunoglobulin A; D022243:Rotavirus Vaccines