The integrated phase III safety profile of the pentavalent human-bovine (WC3) reassortant rotavirus vaccine

Abstract

Background: Rotavirus gastroenteritis is a significant cause of morbidity and mortality.

Objective: To perform an integrated safety analysis of data from the Phase III studies of the pentavalent rotavirus vaccine (PRV).

Methods: Healthy 6- to 12-week-old infants received 3 doses of PRV or placebo at 4- to 10-week intervals in 3 Phase III, blinded, randomized, placebo-controlled trials. Active surveillance for serious adverse events (AE), including intussusception, was performed at 7, 14, and 42 days after each dose. Other AEs occurring within 42 days after each dose were documented on Vaccination Report Cards. Fecal shedding of vaccine-virus strains was evaluated by plaque assay and electropherotyping.

Results: Intussusception and other serious AEs were evaluated among 71,799 vaccinated subjects. Within 42 days after any dose, intussusception occurred among 6 PRV and 5 placebo recipients. All AEs were evaluated among 11 722 vaccinated subjects. Within the week following the first dose, the incidences of fever and irritability were similar among PRV and placebo recipients, although diarrhea and vomiting occurred more frequently among PRV recipients versus placebo recipients (10.4% vs. 9.1% and 6.7% vs. 5.4%, respectively). Fecal shedding of vaccine-virus strains occurred in 8.9% of 360 PRV recipients after the first dose.

Conclusions: Across the 3 Phase III clinical trials, PRV was well tolerated, with no increased clinical risk of intussusception. Fecal shedding of vaccine-virus strains occurred infrequently and in low amounts, suggesting the risk of transmission is unlikely.