A complete three-dose series of pentavalent rotavirus vaccine was 85 percent to 89 percent effective against rotavirus gastroenteritis severe enough to cause emergency room visits or hospital admission in children aged 15 days through 23 months, results of a recently published study indicate.
The study was published online Jan. 18 in the journal Pediatrics, from the American Academy of Pediatrics.
From February through June 2008, researchers from several U.S. sites evaluated the effectiveness of a complete three-dose or partial one- to two-dose immunization with RV5. Four hundred children who were taken to hospital emergency rooms or were admitted for inpatient care with either diarrhea, vomiting or both symptoms met study inclusion criteria; 90 children had confirmed rotavirus from fecal specimens.
Although vaccine effectiveness rates were lower than those demonstrated in pre-licensure trials (94 percent to 96 percent), the researchers noted that this might be because of higher levels of disease severity among pre-licensure study participants.
Study data also revealed positive results for partial immunization, with one dose conferring 69 percent protection and two doses conferring 81 percent protection. As the severity of disease increased, the level of protection also increased, the researchers noted.
“Importantly, our findings indicate that partial immunization with RV5 confers good protection against severe rotavirus disease,” the researchers noted. “Approximately 10 percent to 15 percent of severe rotavirus disease in U.S. children aged less than 5 years occurs before the age of 6 months, when a child can be fully immunized, and the benefits of partial immunization are key for the prevention of severe rotavirus acute gastroenteritis in young infants and children who do not complete their vaccination series.”
This study represented the first post-licensure examination of RV5’s performance in U.S. clinical practice. Although they acknowledged that further research is needed to confirm their findings, they concluded that RV5 was extremely effective in protecting against rotavirus acute gastroenteritis.
Determining the effectiveness of the monovalent rotavirus vaccine (Rotarix from GlaxoSmithKline) independent of, and in conjunction with RV5 is another priority, researchers said.