In 1999, a rotavirus vaccine (Rotashield) was withdrawn from the U.S. market because it was associated with intussusception, a common cause of acute intestinal obstruction in infants younger than one year. Therefore, the Centers for Disease Control and Prevention (CDC) determined whether another rotavirus vaccine, Rotateq, also was associated with bowel obstruction.

After the evaluation of a clinical trial involving 71,725 infants, the CDC determined that there was not a statistically significant risk of intussusception within 42 days after the administration of the vaccine. However, the CDC notes that postmarketing monitoring is necessary for intussusception because infants who routinely received the vaccine may have different characteristics than those in the trial.

The U.S. Food and Drug Administration and the CDC have monitored the postmarketing safety of Rotateq through the Vaccine Adverse Event Reporting System and the Vaccine Safety Datalink. Of the 28,000 infants who were given the vaccine, there were no reported cases of intussusception within 30 days of receiving the vaccine. Therefore, the data do not suggest that the vaccine is associated with intussusception. However, the possibility of an increased risk of intussusception or any other adverse event in the long term could be likely because it is possible that there were underreported data.