ROCKVILLE, Md. -- The FDA has notified physicians that the year since RotaTeq, an oral rotavirus vaccine, was approved, there have been 28 reported post-marketing cases of intussusception. It is not known whether the cases were causal or coincidental, the agency said.
ROCKVILLE, Md., Feb. 14 -- The FDA has notified physicians that in the year since RotaTeq, an oral rotavirus vaccine, was approved there have been 28 reported post-marketing cases of intussusception.
Reminding physicians that "intussusception is a potential complication of RotaTeq," the FDA said it is unknown whether the 28 cases "were caused by the vaccine or occurred by coincidence." There were no deaths due to intussusception.
The FDA said that 28 cases did not exceed the number expected based on background rates of 18 to 43 per 100,000 per year for an unvaccinated population of children ages six to 35 weeks (CDC, unpublished data).
But it issued the notice "to encourage reporting of any additional cases that may have occurred or occur in the future after administration of RotaTeq."
An earlier rotavirus vaccine -- RotaShield, made by Wyeth -- was withdrawn in 1999 after reports linked the vaccine to an increased risk of intussusception, the potentially life-threatening condition that occurs when a portion of the intestine telescopes into a nearby segment of intestine, forming a knot that blocks the intestine.
When RotaTeq was approved, the FDA required increased post-marketing studies as a condition of licensure. Merck, which markets RotaTeq, committed to conducting a post-licensure study of roughly 44,000 children, and the CDC said it would conduct a post-marketing study specifically designed to detect quickly any association between vaccine use and intussusception.
The FDA also required Merck to report cases of intussusception and "all serious adverse events" to the FDA within 15 days of receiving them.
Approximately 3.5 million doses of RotaTeq have been distributed in the United States through February 1, 2007, said the FDA, though not all doses have been administered. Since its licensure on Feb. 3, 2006 until Jan. 31, 2007, 28 cases of intussusception have been reported in the U.S. in infants who received RotaTeq.
These cases were reported to the Vaccine Adverse Event Reporting System (VAERS). The reported 28 cases occurred after dose 1, dose 2 and dose 3. Approximately half of the cases occurred 1 to 21 days after vaccination, with a range of 0 to 73 days.
Sixteen of the 28 infants with intussusception required hospitalization and surgery on their intestine. The remaining 12 infants had reduction of the intussusception by contrast or air enema.
The FDA advised parents to inform a doctor immediately if the child after receiving the vaccine has stomach pain, vomiting, diarrhea, blood in their stool or change in their bowel movements, as these may be signs of intussusception.
Moreover, the FDA said parents should inform the doctor even if symptoms occur several weeks after a vaccine dose.
When the FDA approved RotaTeq it said rotavirus, which causes severe diarrhea, and fever and dehydration in infants, resulted in an estimated 55,000 hospitalizations in the U.S. each year.