Infant-Diarrhea Vaccine: Removed From Use, but Was It Justified?
Oct. 11, 2001 -- A vaccine to treat one of the most common causes of diarrhea in infants was pulled from the market earlier this year, but some researchers are now saying that the vaccine may have gotten a bad rap.
Rotavirus causes diarrhea severe enough to put 50,000 infants in the hospital each year in the U.S., about 20 of whom die. And that's why scientists developed a vaccine in 1998 to combat the virus.
However, soon afterward -- after one and a half million infants had received the vaccine -- reports started surfacing about a serious bowel problem called "intussusception" that many felt might be due to the vaccine, called Rotashield.
These reports of intussusception -- where the bowel lining folds into itself like a telescope, causing obstruction and death of the colon tissue -- eventually led to the vaccine being removed from the market in March of this year.
But researchers led by Lone Simonsen at the National Institutes of Health are raising some doubt that the vaccine was actually causing this potentially deadly bowel problem.
In their study -- published in this week's issue of The Lancet -- Simonsen and colleagues looked at the number of infants under the age of 1 that went into the hospital with intussusception during the time that the vaccine was being used. But instead of finding that more babies were put into the hospital during this period with this bowel problem, they found just the opposite. Fewer infants had to be admitted to the hospital with the telescoping bowel problem than the year prior.
But, interestingly, they did find that infants 7 months and younger were, in fact, slightly more likely to have this problem during the time the vaccine was available.
The researchers suggest that the vaccine may make it more likely for certain susceptible infants to develop intussusception but that this may be offset by fewer cases later in infancy.
Simonsen and colleagues say that this issue warrants further attention since the benefits of Rotashield outweigh the reported risk associated with the vaccine.
They also admit that there are problems with their study, such as their inability to compare cases of intussusception with vaccine records. Thus, they were not able to prove whether the vaccine is or isn't likely to cause the problem.
Andrew J. Hall, who wrote an editorial accompanying the study, agrees that the findings are interesting but don't tell us what we need to know about the link between the vaccine and intussusception.
At this point, it is unlikely that the sole manufacturer of Rotashield, which actually still has a license for the vaccine but just removed it from the market due to safety concerns, will reintroduce the vaccine for general use.
Rotavirus continues to be a big health problem for infants -- and their parents -- and hopefully a vaccine that everyone is comfortable with will ease doctors' and parents' concerns over this very common cause of severe diarrhea.