The level of risk from RotaTeq appears to be only about one-tenth of the risk from Rotashield, an earlier vaccine that was withdrawn from the market in 1999. The risk was found to be concentrated between the third and seventh day after vaccination. The study appears in New England Journal of Medicine on-line.
The study was funded by the FDA through its Mini-Sentinel Post-licensure Rapid Immunization Safety Monitoring (PRISM) project. RotaTeq was licensed in 2006, several years after the withdrawal of Rotashield, which carried a risk of intussusception of approximately 1-1.5 excess cases per 10,000 vaccine recipients. Studies in other countries had identified an increased risk of intussusception from second-generation rotavirus vaccines, including RotaTeq. The Harvard Pilgrim Institute researchers analyzed data for 1.3 million doses of RotaTeq given to infants in the U.S. from 2006 to 2011. The study found that RotaTeq vaccination led to about 1.5 excess cases of intussusception per 100,000 first-dose recipients, or about 1/10 of the risk found for the earlier vaccine. As a result of the study, the FDA approved a change to the RotaTeq product label, and the CDC revised its vaccine information statements for parents, guardians and providers about the risk of intussusception.
“The study team found a small increase in the risk of intussusception following vaccination with the first dose of RotaTeq," said Katherine Yih, PhD, MPH. “However, the benefits of the vaccine in reducing diarrheal disease and averting hospitalizations for severe diarrhea continue to outweigh the risks." she said. “This study demonstrates the value of FDA's Mini-Sentinel project, which has developed the capability to use electronic health data to assess important problems, while ensuring the confidentiality of patients' information,” Yih added.