Adults 18 years and older who have completed their primary vaccination series.
Although COVID-19 vaccination remains effective in preventing severe disease, recent suggest vaccination becomes less effective over time, especially in people aged 65 years and older and at preventing infection or milder illness with symptoms.
According to the CDC: For Pfizer-BioNTech and Moderna, you should get your booster at least 6 months after completing your primary COVID-19 vaccination series. For Johnson & Johnson's Janssen vaccine, you should get the booster at least two months after completing your primary COVID-19 vaccination.
So far, reactions reported after getting a booster shot were similar to those of the two-shot or single-dose primary series. Fever, headache, fatigue and pain at the injection site were the most commonly reported side effects, and overall, most side effects were mild to moderate. However, as with the two-shot or single-dose primary series, serious side effects are rare, but may occur.