What to Expect during and after Your Booster Shot Appointment
Bring your CDC COVID-19 Vaccination Record card to your booster shot appointment so your provider can fill in the information about your booster dose. If you did not receive a card at your first appointment, contact the vaccination site where you got your first shot or your state health department to find out how you can get a card.
You may experience side effects after getting a COVID-19 vaccine. These are normal signs that your body is building protection against COVID-19.
Use v-safe to tell CDC about any side effects. If you enter your booster shot in your v-safe account, the system will send you daily health check-ins.
If You Were Vaccinated Outside of the United States
If you completed a Pfizer-BioNTech, Moderna, or J&J/Janssen COVID-19 vaccine primary series outside of the United States you should follow the guidance above for booster shots. 

Otherwise, if you were vaccinated abroad with other COVID-19 vaccines you can get a booster shot if you are 16 years or older and you either: 

Received all the recommended doses of a World Health Organization emergency use listing (WHO-EUL) COVID-19 vaccineexternal icon, not approved or authorized by the U.S. Food and Drug Administration (FDA) 
Or completed a mix and match series composed of any combination of FDA-approved, FDA-authorized, or WHO-EUL COVID-19 vaccines 
If you meet the above requirements you can get a single booster shot of Pfizer-BioNTech COVID-19 vaccine at least 6 months after getting all recommended doses or completing a mix and match COVID-19 vaccine series.