In the past, vaccines against rotavirus, an infection causing severe diarrhea, have been linked with serious bowel problems and blockages in infants, but a large-scale study of over three-quarters of a million doses should clear concerns about currently available products.
The vaccines had been linked with a condition known as intussusception, in which part of the bowel slides into itself, causing a blockage. The study looked at babies who had received Merck's ($MRK) RotaTeq vaccine between 2006 and 2010 and were enrolled in the Vaccine Safety Datalink--786,725 doses in total. The researchers saw the children receiving it were no more likely to be diagnosed with the condition than those who had not had the shot.
"We can't rule out that a low-level risk could exist," Harvard Medical School's Irene Shui told Reuters Health, particularly in a bigger sample. However, she added, "our results do add to the message that even if there was a low-level risk of intussusception, the benefits of the vaccine far outweigh those risks."
Back in 2007, the FDA sent out warnings that Merck's rotavirus vaccine, RotaTeq, could cause bowel problems in children, and even further back, in 1999, Wyeth's RotaShield vaccine was withdrawn for its links with the same problem. Rotavirus infection is the leading cause of diarrhea in children and babies and can lead to hospitalization and death. "I think it's important for both parents and physicians to realize that vaccines like the rotavirus vaccine have had a tremendous public health benefit, but every treatment or vaccine has some risk," Shui concluded.