It is unknown how the body will respond in this case, or if symptoms will develop. It is important to understand that it is not possible to get COVID-19 from the vaccine (shot) itself. If you tested positive, then you  got COVID-19 before or shortly after receiving the vaccine (shot) and should isolate (https://www.coronavirus.in.gov/files/20_Family%20isolation_COVID-19_8-10-20.pdf) as recommended by the CDC and Indiana Department of Health.

You also should continue wearing a mask and quarantining if you are in close contact of a positive case, even if you have gotten the vaccine (shot). Studies only looked at whether a person who got a shot developed COVID-19 (symptoms and positive test). They did not study whether receiving the vaccine (shot) decreased the chance that a person who got a shot could spread the virus.