As I recall, if you’re 65+ (I don’t think you are), the recommendation is to get a second booster after 5 months.

If you’re younger than 65 and have a healthy immune system, then most of your immunity will be gone after 6 months.

So in my partially informed opinion, I’d say that you have some immunity left.

As Brian posted. 5 to 6 months. So you are at about 5 and a half months. I would schedule it now since it may take a while.

The previous booster is not used up and gone from your system, rather it is no longer at a desirable strength.
Don’t stress on it, but do schedule another boost.

If you don’t test, then you don’t know.

I think you have to be 50 years of age or older to get the second booster. Or if you are immunocompromised.

Heard it was 6 months for 50 plus year olds like myself until I went to our State website and saw that it was 4 months.

Got my second booster just 5 days ago, 6 months after my first. Guess I had low protection for 2 months?

During that period, never had symptoms and the two self-tests I did came out negative.

Better ask your doctor or the pharmacist where you get your shots.