Efficacy of RIX4414 live attenuated human rotavirus vaccine in Finnish infants.
BACKGROUND
Rotavirus gastroenteritis, a major cause of mortality and morbidity worldwide, is a vaccine-preventable disease. New safe and effective candidate rotavirus vaccines are needed to replace the withdrawn rhesus rotavirus-based oral vaccine.


METHODS
We evaluated a monovalent human rotavirus vaccine, serotype G1, strain RIX4414, for efficacy, immunogenicity and safety in a randomized, double blind, placebo-controlled trial in Finland. We randomly allocated 405 healthy infants to receive 2 doses of vaccine or placebo (ratio 2:1) at approximately 2 and 4 months of age. The infants were followed during 2 rotavirus epidemic seasons (2000-2002) for acute gastroenteritis. Rotaviruses in diarrheal stool samples were primarily detected by enzyme-linked immunosorbent assay and confirmed and G-typed by reverse transciption-polymerase chain reaction.


RESULTS
The vaccine was well-tolerated. No vaccine-related serious adverse events were observed during the study period. Rotavirus IgA (enzyme-linked immunosorbent assay) seroconversion rate was 80% after 2 doses. Thirty-eight cases of rotavirus gastroenteritis were detected during the entire follow-up period; 35 of these were of the G1 type. RIX4414 vaccine significantly decreased the occurrence of any rotavirus compared with placebo. Efficacy during the first rotavirus epidemic season was 73% [95% confidence interval (95% CI), 27-91%] and 90% (95% CI 10-100%) against any and severe rotavirus gastroenteritis, respectively, and during the entire follow-up period 72% (95% CI 42-87%) against any and 85% (95% CI 42-97%) against severe rotavirus gastroenteritis (P < 0.05 for all comparisons).


CONCLUSIONS
RIX4414 strain of G1 human rotavirus vaccine was well-tolerated, immunogenic and efficacious in infants against rotavirus gastroenteritis during a 2-year period. To further increase vaccine "take" and efficacy, a higher dose of this vaccine may be considered for future efficacy trials.
Vesikari
Timo
T
Vaccine Research Center, University of Tampere Medical School, FIN-33014 Tampere, Finland. timo.vesikari@uta.fi
Karvonen
Aino
A
Puustinen
Leena
L
Zeng
Shang-Qin
SQ
Szakal
Evelyn Dora
ED
Delem
Andrée
A
De Vos
Beatrice
B
D000284:Administration, Oral; D004311:Double-Blind Method; D005260:Female; D005387:Finland / Q000453:epidemiology; D005759:Gastroenteritis / Q000517:prevention & control / Q000821:virology; D006801:Humans; D007223:Infant; D008297:Male; D012400:Rotavirus Infections / Q000276:immunology / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology
D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated