Remember which vaccine you got because it's important!

 Why?

Because when you get a booster It MUST be compatible with whatever vaccine(s) you received.

Johnson and Johnson is a single shot.

Pfizer and Moderna are two shots. This might make it easier to remember which vaccine(s) you got.

I just learned that Astrazeneca is a two shot vaccine.

So, this must mean that Johnson and Johnson is the ONLY single shot vaccine.