Age at First Rotavirus Vaccination and Risk of Intussusception in Infants: A Public Health Modeling Analysis

Introduction The epidemiology of naturally occurring intussusception is known to increase significantly between the ages of 3 and 8 months. Post-licensure studies have reported a fivefold and twofold increase in intussusception in the first week after the first dose and second dose, respectively, of current rotavirus vaccines (RVs). Purpose We carried out a public health risk analysis to model the impact of age at first vaccination in relation to rotavirus vaccination and risk of intussusception in infants. Method We created a static model for a birth cohort followed until 1 year old to estimate the number of excess intussusception hospitalizations which could be caused by three different infant rotavirus vaccination schedules. A relative risk of 5.45 in the first 7 days after the first dose and 1.75 in the first 7 days after the second dose was used in the model. Result We estimated that the risk of intussusception would be the lowest at about 1 in 49,000 if both first and second dose RVs were given at < 3 months of age followed by 1 in 41,000 if first dose RVs were given at < 3 months and second dose RVs were given at 3-5 months. It would be highest at about 1 in 11,000 if infants received both doses when > 3 months old. Conclusion Our epidemiological example illustrates the importance of ensuring that the first two doses of RVs are administered in infants < 3 months old whenever possible to minimize the risk of intussusception as an adverse event following rotavirus vaccination.