How many doses of the vaccine are there? When do I get the second dose?

To be fully protected you must get 2 doses of the Pfizer vaccine. The second dose should be at least 21 days (3 weeks) after the first dose. You may not be fully protected until 7 days after the second dose.
Whilst it is best to take the second dose 3 weeks after the first, if for some reason you can’t do this, it is still OK to take it later.