Monovalent rotavirus vaccine elevates intussusception risk

A comparison of the risk of intussusception after receipt of monovalent versus pentavalent rotavirus vaccine or versus historical background rates of intussusception found that the monovalent vaccine significantly increases that risk.

Investigators analyzed data for almost 208,000 doses, both first and second, of monovalent rotavirus vaccine and almost 2 million doses of pentavalent rotavirus vaccine during a roughly 5-year period. Among infants aged 4 to 34 weeks old who received monovalent vaccine, investigators identified 6 cases of intussusception within 7 days of administration of either the first or second dose, resulting in a significant relative risk of 8.4 compared with historical background rates.

For the pentavalent rotavirus vaccine, 8 intussusception cases were observed, a nonsignificant relative risk of 1.1. The relative risk of intussusception within 7 days after doses 1 and 2 of monovalent rotavirus vaccination, compared with this risk after doses 1 and 2 of the 3-dose pentavalent rotavirus vaccination series, was 9.4. Investigators estimated that 5.3 per 100,000 infants vaccinated with 2 doses of monovalent rotavirus vaccine were at risk of intussusception (Weintraub ES, et al. N Engl J Med. 2014;370[6]:513-519).

Commentary: This article was published simultaneously with a second, large postlicensure assessment of monovalent and pentavalent rotavirus vaccines in the United States. Together these articles suggest that not just the monovalent but the pentavalent rotavirus vaccine as well are linked to a slightly increased risk of intussusception (Yih WK, et al. N Engl J Med. 2014;370[6]:503-512). In an accompanying editorial, Glass and Parashar help to put this in perspective by reminding us what we get for that risk. They cite estimates that in an annual cohort of 4.5 million US infants, rotavirus vaccine might cause 45 to 213 cases of intussusception while preventing more than 50,000 hospitalizations and more than 150,000 emergency department visits (Glass RI, et al. N Engl J Med. 2014;370[6]:568-570). I suspect that any of us who remembers a deathly ill infant with rotavirus will be willing to take this risk. -Michael Burke, MD

Ms Freedman is a freelance medical editor and writer in New Jersey. Dr Burke, section editor for Journal Club, is chairman of the department of Pediatrics at Saint Agnes Hospital, Baltimore, Maryland. He is a physician contributing editor for Contemporary Pediatrics. The editors have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.