Two papers in the New England Journal of Medicine have looked at the intussusception risk in US infants after rotavirus vaccination. Weintraub et al. report an estimated attributable risk of intussusception after two doses of monovalent vaccine of 5.3 per 100,000 infants vaccinated. Yih et al. reported that the first dose of pentavalent vaccine was associated with 1.5 excess cases of intussusception per 100,000 infants vaccinated. Secondary analysis suggested a potential risk with monovalent vaccine, but this part of the study was underpowered. Both groups stress the need to view the risk in light of the benefits of vaccination.