Q- How many COVID 19 vaccine doses are needed and why?
Pfizer and Moderna vaccines require two shots. The first shot starts building protection, but everyone has to come back a few weeks later for the second one to get the most protection the vaccine can offer.
The first shot primes the immune system, helping it recognize the virus, and the second shot strengthens the immune response.
Second Dose of COVID 19 Vaccine-
To get the most protection, Pfizer and Moderna COVID-19 mRNA vaccines will need 2 shots. The timing between your first and second shot depends on which vaccine you received. You should get your second shot:
Moderna- 1 month (or 28 days) after your first shot.
Pfizer-BioNTech- 3 weeks (or 21 days) after your first shot.You should get your second shot as close to the recommended 3-week or 1-month interval as possible. However, there is no maximum interval between the first and second doses for either vaccine. You should not get the second dose earlier than the recommended interval.
Get the second shot even if you have side effects after the first shot, unless a vaccination provider or your doctor tells you not to get a second shot.
Reference- 1. Answering Patients’ Questions about COVID-19 Vaccination | CDC. (2020, November 25). Www.cdc.gov. https://www.cdc.gov/vaccines/covid-19/hcp/answering-questions.html