When can I get a second dose of a vaccine?

You should not be scheduled to receive the second dose earlier than recommended (i.e., 3 weeks [Pfizer-BioNTech and Novavax] or 1 month [Moderna]). 

If you received the Pfizer-BioNTech or Novavax vaccine, you should receive your second dose 3 weeks (21 days) after your first dose. 

If you received the Moderna vaccine, you should receive your second dose 1 month (28 days) after your first dose.

However, second doses administered within a grace period of 4 days earlier than the recommended date for the second dose are still considered valid.

Visit the CDC website for more information.