It depends on the type, some (not quite a small number) of vaccines contain an attenuated version of the virus. Some are available in multiple forms, like Salk

It depends on the type, some (not quite a small number) of vaccines contain an attenuated version of the virus. Some are available in multiple forms, like Salk and Sabin polio vaccines. However, the risk of getting sick from the vaccine is small compared to the risk of getting sick without the vaccine. When the risk levels get close to equal, the vaccine type is changed to the less-risky but less-effective type. Attenuated virus vaccines are usually more effective than inactive virus ones.