Studies show that after getting vaccinated against COVID-19, protection against the virus may decrease over time and be less able to protect against the Delta variant.
Although the COVID-19 vaccination for adults aged 65 years and older remains effective in preventing severe disease, recent data shows that among healthcare and other frontline workers, vaccine effectiveness against COVID-19 infections can decrease over time.
Emerging evidence has shown that this lower effectiveness is likely due to the combination of decreasing protection as time passes since getting vaccinated (e.g., waning immunity) as well as the greater infectiousness of the Delta variant.
Data from a small clinical trial show that a Pfizer-BioNTech booster shot increased the immune response in trial participants who finished their primary series 6 months earlier. With an increased immune response, people should have improved protection against COVID-19, including the Delta variant.
Certain populations initially vaccinated with the Pfizer-BioNTech vaccine are now eligible to get a booster shot at this time. They include:
- People aged 65 years and older
- Adults 50–64 years with underlying medical conditions
- Residents or employees of long-term care facilities
- People aged 18–49 years with underlying medical conditions
- People aged 18–64 years at increased risk for COVID-19 exposure and transmission because of occupational or institutional settings such as:
- First responders (healthcare workers, firefighters, police, congregate care staff)
- Education staff (teachers, facilities staff, daycare workers)
- Food and agriculture workers
- Manufacturing workers (and manufacturing facilities workers)
- Corrections workers (custodial staff and maintenance workers)
- U.S. Postal Service workers
- Public transit workers (including custodial staff and maintenance workers)
- Grocery store workers
Adults who work in these industries or reside in certain settings (e.g., correctional facilities, homeless shelters) may be at an 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 are eligible to get a booster shot after considering their individual risks and benefits.
According to the CDC, these recommendations may change in the future as more data become available. Read more at on the CDC website.