evidence: Rockville (MD): Agency for Healthcare Research and Quality (US); 2021 May. [...] Centers for Disease Control and Prevention. Immunization Schedules: Table 1. Recommended Child and Adolescent Immunization Schedule for ages 18 years or younger, United States, 2021. https://www​.cdc.gov/vaccines​/schedules/hcp​/imz/child-adolescent.html. Accessed on February 16, 2021. Background 230. Centers for Disease Control and Prevention. Immunization Schedules: Table 1. Recommended Adult Immunization Schedule for ages 19 years or older, United States, 2021. https://www​.cdc.gov/vaccines​/schedules/hcp/imz/adult.html. Accessed on February 16, 2021. Background 231.