My understanding is that the COVID boosters lose most of their efficacy after six months. I got my bivalent booster ten months ago. What happens if I just walk into Walgreens and ask for another? Will they give it to me?

The CDC page says "you only get one booster for the rest of your life", because when they wrote that page they never could have predicted that this would still be going on a year later.

Update: I read the misordered scribbles on my paper card wrong, I guess April was shot 4, and I got shot 5 in September (according to the QR code). Which does not explain why they wrote 6/30/2023 on the paper card...