Utilizing IIS data to identify vaccination patterns during vaccine shortages

Since 2000, vaccine shortages have impacted vaccines used to prevent at least nine vaccine preventable diseases. Monitoring vaccine use during shortages can identify children not receiving vaccine as recommended and can support the development of educational messages and interventions to ensure all children are appropriately vaccinated. Data from the Immunization Information System (IIS) Sentinel Site Project, which includes eight IIS with high provider and child participation rates, were used to assess vaccine use and adherence to revised Advisory Committee for Immunization Practices (ACIP) recommendations during two recent vaccine shortages. In response to a 2006 shortage of meningococcal vaccine, ACIP recommended vaccine deferral among 11-12 year olds with continued vaccination of adolescents entering high school and college. IIS data showed decreased administration of meningococcal vaccine to adolescents aged 11-12 years during the shortage, followed by increased administration in this age group once the shortage ended. In response to a shortage of Haemophilus influenzae type B (Hib) vaccine in 2007, ACIP recommended deferral of the booster dose, typically administered between age 12-15 months. However, IIS data showed decreased administration of the 3rd dose of the Hib vaccine primary series, contrary to ACIP recommendations. This information enabled CDC to develop and distribute educational messages to clarify recommendations. Since IIS include timely, provider-verified immunization data and exist in all 50 states and 6 large cities, they serve as an excellent data sources to monitor vaccine use during shortages.