There appears to be quite a bit of confusion about what immunity means for the COVID-19 vaccines that are in use in the U.S. and Europe. These are the 2 mRNA-based vaccines and the DNA-based vaccine. 

Without getting into the science behind my comments, for these vaccines immunity means that the person who has been vaccinated with both doses will be protected against getting severe COVID-19, the kind that causes hospitalization and the need for artificial ventilation and possibly results in death.

The question is: Can I get infected with the SARS-CoV2 coronavirus after getting the vaccine?

The answer is: YES!

Vaccinated people can still get infected with the virus that causes COVID-19, but their immune system will react in such a way that severe disease symptoms are prevented. 

Because a vaccinated person can still get infected with the virus, he or she can still infect a nonvaccinated person who could be someone that gets severe COVID-19 and winds up in the hospital or even dies. [UPDATE 7 April 2021: The vaccines reduce transmission. So, this is less worrisome than previously thought. See Vaccine Effectiveness Against Severe COVID-19 and Transmission ]

This means that vaccinated people need to keep wearing their masks when in public. The vaccinated person still need to protect other unvaccinated people from the possibility of contracting the virus.

The only potentially safe time to not wear a mask in the presence of others is if all of the people present have received both doses of a vaccine against SARS-CoV2, the virus that causes COVID-19. Even then, if one of the vaccinated people present is infected with the virus, this person could infect the other vaccinated people present. Some of whom will get sick, they are just not likely to get severely ill from COVID-19. Critically, the exposure of vaccinated individuals to other vaccinated individuals who are infectious with the virus could lead to the infection of not only the vaccinated person but others who have not been vaccinated and who come into close contact with the vaccinated and now infected person.

So, even if you have received both doses of the vaccine, keep wearing your mask to protect the unvaccinated from you. You could still transmit the virus to someone else. You could be just like the asymptomatic people who go on to infect someone who then develops severe COVID-19.

The vaccines protect against getting severe COVID-19, not against getting infected with SARS-CoV2.

Get vaccinated as soon as you are eligible but keep wearing a mask to protect others. Just because you got the vaccine and now won’t get sick with COVID-19 doesn’t mean that you can’t get someone you come into contact with seriously ill with COVID-19. [Update 7 April 2021: The data show that you are much less likely to transmit the virus if you do have asymptomatic COVID-19 after being vaccinated.]