The CDC recommends that certain populations receive a booster shot of Pfizer-BioNTech’s COVID-19 Vaccine at least 6 months after completion of their 2-dose Pfizer-BioNTech vaccine series. See full details: https://bit.ly/3mrK4Z5
Data Supporting Need for a Booster Shot
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 COVID-19 vaccination for adults aged 65 years and older remains effective in preventing severe disease, recent data pdf icon[4.7 MB, 88 pages] suggest vaccination is less effective at preventing infection or milder illness with symptoms. Emerging evidence also shows that among healthcare and other frontline workers, vaccine effectiveness against COVID-19 infections is decreasing over time. 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.