So I got my 3rd shot last week. Wasn't planning on it, but was at a checkup, they asked, and I basically said "F it, go ahead". Arm hurt, no other symptoms, like the first 2 shots for me.

The doctor's office just called and said the dose they gave me had been left in their fridge too long and may not be as effective, so I need to come in for a booster on my booster (4th shot).

I really don't want to. Primarily since the vaccine cards are to be treated like a passport, and I don't want someone to mar the card by scratching out the 3rd dose and writing something else in. Seems like more of a headache to explain why something is crossed out on there in the future.

How do you otherwise gauge how "protected" you are. There's always some risk that can't be avoided or minimized. What's the the decrease in effectiveness of a dose that was left in a refrigerator too long?

If I'm fully vaccinated but only 75% boosted, what does that really mean?

What if it's only 30% boosted?

Is skipping this 4th shot really going be the difference between life and death, or even a relatively light bout of COVID vs hospitalization?