Two new studies in the United States (US) find no increased risk of intussusception following administration of rotavirus vaccines in infants. These studies add to the growing body of scientific evidence that the benefits of rotavirus vaccines to reduce deaths and hospitalizations from severe rotavirus disease far outweigh the possibility of a low-level intussusception risk.
Vaccination offers the best hope for preventing severe rotavirus disease and the deadly dehydrating diarrhea that it causes. More than 90% of rotavirus deaths are in low-income countries (the majority are GAVI-eligible) where vaccination is not in widespread use and access to urgent care for severe rotavirus diarrhea is limited or unavailable. Rotavirus vaccines are a safe, cost-effective intervention for countries to prioritize now.
“Risk of intussusception following administration of a pentavalent rotavirus vaccine in US infants,” published today in the Journal of the American Medical Association (JAMA), examined the rates of intussusception in US infants during the 1 to 7-day and 1 to 30-day windows following vaccination with RotaTeq® from the period of May 2006 to February 2010, and did not find an increased risk of intussusception in either risk window. Researchers compared rates of intussusception in infants who had received RotaTeq® with both those who received other non-rotavirus vaccines and with the expected number of intussusception-related healthcare visits based on 2001 to 2005 rates (prior to the US licensure of RotaTeq®). The researchers also note that rotavirus vaccines have made a tremendous public health impact in the US by contributing to large declines in severe rotavirus disease, to substantial reductions of rotavirus-related hospitalizations, and to dramatic decreases in health care utilization for diarrheal complications.
“Hospitalizations for intussusception before and after the reintroduction of rotavirus vaccine in the United States,” published last month in the Archives of Pediatric Adolescent Medicine examined hospital discharges for intussusception among US infants before and after the introduction of RotaTeq® and Rotarix® vaccines and found that there has not been an increase in the number of hospital discharges for intussusception among US infants following vaccine introduction.
Intussusception is when one portion of the bowel slides into the next, much like the pieces of a telescope. When this occurs, it creates a blockage in the bowel and can lead to bleeding and infection. In some cases, surgery is required. It is a rare occurrence and occurs naturally, primarily in infants between two and nine months of age. In most cases the cause is unknown.
Intussusception was found to be a rare but significant side effect with RotaShield®, the first-generation rotavirus vaccine originally available in the US that was voluntarily withdrawn from the US market by the manufacturer (Wyeth) in 1999. Because of the prior association, large pre-licensure clinical trials were conducted with the current rotavirus vaccines—RotaTeq® and Rotarix®—with no increased risk observed. However, recent international post-licensure evaluations conducted in Australia, Mexico, and Brazil suggest the possibility of a low-level elevated risk in infants during the first week after the first vaccination. The JAMA researchers were unable to explain why their findings differed from those in Latin America and Australia but noted that because intussusception is a rare event, and environmental and genetic factors may play a role in natural rates of intussusception, they cannot entirely exclude the possibility of a very low-level risk.
For more information on intussusception from the US Centers for Disease Control and Prevention, please click here. For more information on intussusception from the Government of Australia, please click here. To read more about the recent studies on rotavirus vaccines and their significant impact on hospitalizations in the US please click here.
