Renewed attention to possible rotavirus vaccine link to intussusception

A fairly significant amount of alarm was raised by an FDA statement last week titled "Information on RotaTeq and Intussusception". The statement reports 28 cases of intussusception -- the significant intestinal complication that led to the removal of the first rotavirus vaccine, RotaShield, in 1998 -- in children following administration of RotaTeq.

But what may have seemed at first glance to be a major announcement about the vaccine's safety was clarified later in the statement...

"Intussusception can occur spontaneously in the absence of vaccination. Of the reported 28 cases of intussusception, the number that may have been caused by the vaccine, or occurred by coincidence, is unknown."

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"The number of intussusception cases reported to date after RotaTeq administration does not exceed the number expected based on background rates of 18-43 per 100,000 per year for an unvaccinated population of children ages 6 to 35 weeks (CDC, unpublished data)."

In other words, there's no reason to be alarmed about the number of cases reported to date, but the statement, not unsurprisingly, did just that. This AP story by Andrew Bridges originally did not include any information about the background rate, likely contributing to the Alliance for Human Research Protection (and others, no doubt) misinterpreting the FDA item. "Merck rotavirus vaccine linked to 28 reports of life-threatening effect," is how the AHRP item describes the announcement, not at all what the FDA said.

CDC promptly released a statement attempting to clear up confusion. Among the 'key facts' they list:

• "We are not surprised by the number of reported intussusception cases following RotaTeq vaccination."
• "Intussusception, a form of bowel obstruction, occurs spontaneously in the absence of vaccination."
  
• "This notice does not mean there is a problem with the RotaTeq vaccine."

There's been no detectable coverage of this topic in the media since the initial FDA statement last week. It will, however, be discussed at this week's meeting of the ACIP, the agenda for which can be viewed here.