Impact of routine childhood immunization in reducing vaccine-preventable diseases in the US

Background and objectives: Current routine immunizations for children aged ≤10 years in the United States (US) in 2019 cover 14 vaccine-preventable diseases. We characterize the public-health impact of vaccination by providing updated estimates of disease incidence with and without universally recommended pediatric vaccines.

Methods: Pre-vaccine disease incidence was obtained from published data or calculated using annual case estimates from the pre-vaccine time periods and US population estimates during the same time period. Vaccine-era incidence was calculated as the average incidence over the most recent 5 years of available surveillance data or obtained from published estimates (if surveillance data were not available). We adjusted for underreporting and calculated the percent reduction in overall and age-specific incidence for each disease. We multiplied pre-vaccine and vaccine-era incidence rates by 2019 US population estimates to calculate annual number of cases averted by vaccination.

Results: Routine immunization reduced the incidence of all targeted diseases, leading to reductions in incidence ranging from 17% (influenza) to 100% (diphtheria, Haemophilus influenzae type b, measles, mumps, polio, and rubella). For the 2019 US population of 328 million people, these reductions equate to >24 million cases of vaccine-preventable disease averted. Vaccine-era disease incidence estimates remained highest for influenza (13,412/100,000) and Streptococcus pneumoniae-related acute otitis media (2,756/100,000).

Conclusions: Routine childhood immunization in the US continues to yield considerable sustained reductions in incidence across all targeted diseases. Efforts to maintain and improve vaccination coverage are necessary to continue experiencing low incidence levels of vaccine-preventable diseases.