A single booster dose of the COVID-19 vaccine by Pfizer-BioNTech (30 mcg in 0.3 mL) may be administered

to adults 18 years and older at least 5 months after completion of a non-FDA authorized primary vaccination as long as the primary vaccine has been issued Emergency Use Listing (EUL) by WHO. Since the AstraZeneca vaccine has been issued EUL, recipients 18 and older can receive a Pfizer-BioNTech booster if 5 months have passed since their completion of the AstraZeneca primary vaccination. Please see the list of vaccines that have received an EUL from WHO for more information.