COVID-19 Vaccine booster shots are available for Pfizer-BioNTech vaccine recipients who completed their initial series at least 6 months ago and are at least 65 years of age or living in a residential community.  Also, adults aged 18–64 years who work or reside in certain settings (e.g., health care, schools, correctional facilities, homeless shelters) may be at increased risk of being exposed to COVID-19, which could be spreading where they work or reside. Since that risk can vary across settings and based on how much COVID-19 is spreading in a community, people aged 18–64 years who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting may get a booster shot after considering their individual risks and benefits. This recommendation may change in the future as more data become available. 

At this time, the Pfizer-BioNTech booster authorization only applies to people whose primary series was Pfizer-BioNTech vaccine. People in the recommended groups who got the Moderna or J&J/Janssen vaccine may need a booster shot. More data on the effectiveness and safety of Moderna and J&J/Janssen booster shots are expected soon. With those data in hand, CDC will keep the public informed with a timely plan for Moderna and J&J/Janssen booster shots.

Read more at the CDC