Are booster shot the same formulation as existing vaccines? 

Yes. COVID-19 booster shots are the same formulation as the current COVID-19 vaccines. However, in the case of the Moderna COVID-19 vaccine booster shot, it is half the dose of the vaccine people get for their initial series. 

If we need a booster shot are the vaccines working? 

 Yes. COVID-19 vaccines are working well to prevent severe illness, hospitalization, and death, even against the widely circulating Delta variant. However, public health experts are starting to see reduced protection, especially among certain populations, against mild and moderate disease. 

 What are the risks of getting a booster shot? 

So far, reactions reported after getting a booster shot were similar to that of the 2-shot or single-dose initial 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 2-shot or single-dose initial series, serious side effects are rare, but may occur. 

Am I still considered “fully vaccinated” if I don’t get a booster shot? 

Yes. Everyone is still considered fully vaccinated two weeks after their second dose in a 2-shot series, such as the Pfizer-BioNTech or Moderna vaccines, or two weeks after a single-dose vaccine, such as the J&J/Janssen vaccine. 

When can I get a COVID-19 booster shot if I am NOT in one of the recommended groups? 

Additional populations may be recommended to receive a booster shot as more data become available. The COVID-19 vaccines approved and authorized in the United States continue to be effective at reducing risk of severe disease, hospitalization, and death. Experts are looking at all available data to understand how well the vaccines are working for different populations. This includes looking at how new variants, like Delta, affect vaccine effectiveness. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html