Rotavirus live, oral, pentavalent vaccine

On February 3, 2006, the US Food and Drug Administration (FDA) approved a live, oral, pentavalent (G1-G4, P1[8]) human-bovine reassortant rotavirus vaccine for the prevention of rotavirus gastroenteritis (RVGE) in infants in the United States. The Advisory Committee of Immunization Practices of the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) recommended routine immunization of infants using 3 doses of the oral pentavalent rotavirus vaccine (PRV) at 8, 12, and 24 months of age, with the first dose administered between 6 and 12 weeks of age and subsequent doses administered at 4- to 10-week intervals.

This article reviews the composition, clinical efficacy, adverse events, and cost-effectiveness associated with its use.

Relevant literature was identified through searches of MEDLINE (1990-June 2007) and International Pharmaceutical Abstracts (1990-July 2007). Search terms included, but were not limited to, RotaTeq, PRV, intussusception, rotavirus infection, and cost-effectiveness. Further publications were selected from the reference lists of identified articles. Guidelines for use were identified from the Web sites of the CDC and the AAP.

Two published Phase III clinical trials involving the PRV were identified. The Rotavirus Efficacy and Safety Trial (REST) and the Concomitant Use Study, a subanalysis of REST, found that PRV was efficacious and well tolerated. The vaccine was associated with preventing RVGE of any severity in 74% of patients and severe RVGE in 98%. The combined prevalence of hospitalizations and emergency department (ED) visits was reduced by 94.5% (95% CI, 91.2%-96.6%), including a decrease in hospitalizations of 95.8% (95% CI, 90.5%-98.2%) and a decrease in ED visits 93.7% (95% CI, 88.8%-96.5%), with vaccine administration compared with placebo. There were also reductions in physician's office visits of 86% (95% CI, 73.9%-92.5%) and the number of workdays lost for parents (65 vs 487). There were no confirmed cases of intussusception due to the vaccine. The prevalences of fever, diarrhea, and vomiting were not significantly different between the vaccine and placebo groups. Overall, the vaccine was well tolerated. The second study, a multicenter, randomized, placebo-controlled trial, found that PRV was efficacious, well tolerated, and immunogenic at the end of the vaccine's shelf-life. The vaccine was associated with preventing RVGE of any severity in 72.5% of cases and severe RVGE in 100% of cases. No cases of intussusception were reported. The Concomitant Use Study found that PRV could be administered concomitantly with other routine vaccinations during the first 24 weeks of life. Recently, the FDA's Vaccine Adverse Event Reporting System (VAERS) received 28 reports of cases that occurred after the first, second, and third doses. Approximately 50% of cases occurred 1 to 21 days after vaccination. Sixteen of the infants required hospitalization, while the remaining 12 required contrast or air enema intervention to reduce the intussusception.

Based on the results from published studies, PRV appears effective in decreasing the prevalence of RVGE in the United States. Despite evidence from the large trial and no reported cases of intussusception, this event has been reported to VAERS. Continued postmarketing surveillance by the manufacturer, together with the VAERS and the CDC, will confirm whether use of the vaccine increases the risk for intussusception.