Mrrzy's right. The vaccines haven't been tested for ability to stop the spread. I probably don't have up-to-date information, but I know the most recent J&J one wasn't.

They still advise wearing masks, washing hands, and social distancing, even if you've had the vaccine.

BUT if you can reduce the severity of this virus to that of a bad cold, and know you won't die from it, it's worth getting the shot.