We actually don’t know yet whether or not immunity conferred from a vaccine makes it so you cannot transmit the virus to others who are not immune. It’s possible, but we don’t have data to support that yet. Continue to wear your mask and social distance even after your vaccine! https://twitter.com/jameshamblin/status/1352042600585424897

Basically, the vaccine makes a good systemic antibody response so you won’t get very sick with Covid if you’re infected, but it doesn’t stop you from getting infected and potentially replicating the virus in your nasal cavity, where you can then spread it to others

A good thread that goes deeper: https://twitter.com/katherineefoley/status/1349065200109035522