(RxWiki News) The two forms of the rotavirus vaccine currently administered to children do not cause the same gastrointestinal problems as the previous version of the vaccine.
The original rotavirus vaccine, called Rotashield, was pulled from use in 1999, a year after it was introduced, because it was associated with an increase in the number of intussusception cases.
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Intussusception is a bowel obstruction where one part of the bowel slips into another part. The condition can be fatal, but the current versions of the vaccine, RotaTeq and Rotarix, don't appear to increase cases of the problem, according to a new study.
Joe Zickafoose, MD, of the Child Health Evaluation and Research Unit at the University of Michigan, led a study that sifted through data from a national database that contains a sample of the records from 80 percent of all children's hospital discharges.
They looked at the records of children under age one since the vaccine is given at two months, four months and six months, and they focused on the years before the new vaccine was re-introduced, from 1997 to 2006.
Although they anticipated finding 36 hospitalizations per 100,000 infants related to the bowel disorder, they actually only found 33.3, so it's improbable that the vaccine caused more intussusception cases.
According to Dr. Paul Offit, director of the Vaccine Education Center at the Children's Hospital of Philadelphia and the inventor of the RotaTeq vaccine, researchers were uncertain why the first vaccine appeared to cause intussusception in one of approximately 10,000 children who received it. So, they weren't sure whether the new vaccines would cause similar issues.
He said additional studies have since led researchers to believe that rotavirus itself can cause intussusception in rare cases, approximately 1 in 100,000.
"So, the question becomes, which is rarer - intussusception after natural infection or intussusception after vaccination," Offit told dailyRx. "There's an easy way to figure this out. If vaccine causes intussusception more commonly than the disease does, then the rate of intussusception will go up in a highly vaccinated population."
If, however, the infection causes the intussusception more often, then a vaccinated population will have fewer cases of the condition.
"The study by Zickfoose and coworkers suggests that both vaccine and natural infection induce intussusception at about the same rate," said Offit, who was not involved with the study. "So there was no change in the incidence of intussusception."
This means receiving the vaccine does not pose a higher risk than skipping it. He added that additional studies should be done to confirm these findings.
"We hope that our study provides information that will continue to reassure parents that the benefits of rotavirus vaccine outweigh the risks," Zickafoose said.
Over 70 percent of infants in the U.S. have been immunized against rotavirus, which causes diarrhea, vomiting and abdominal pain. It often requires hospitalization for children and is responsible for thousands of deaths in children overseas.
The study was funded by grants from the National Institute of Child Health and Human Development and from the Michigan Institute for Clinical and Health Research. It appears in this week's Archives of Pediatric Adolescent Medicine. The authors had no financial disclosures to report.