What Do You Think? Answers!

True.  COVID-19 vaccine (Pfizer) is administered as a 2-dose series, separated by 21 days.
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The COVID-19 vaccine (Pfizer) schedule is 0, 21 days.  


False. The same vaccine product does not have to be used for both doses. Another COVID-19 vaccine product can be used to complete the series. 

A series started with COVID-19 vaccine (Pfizer) should be completed with the same product. There have been no trials testing the efficacy of a mixed-product series – that is, a series that includes 2 different COVID-19 vaccine products. 


False. Administer 0.5 mL of vaccine by intramuscular injection.

The correct dosage (amount) is 0.3 mL. Administer the vaccine by intramuscular (IM) injection in the deltoid muscle of the arm. 



Page last reviewed: August 26, 2021