@snorris I’m sorry to be the bearer of bad news, but I really doubt your husband has any protection to the vaccine if he tested negative. That means his immune system didn’t react to the vaccination by making antibodies.
I’m a bone marrow transplant patient, still on a low dose of anti inflammatory meds and have only received one dose of Pfizer one month ago. I needed to be tested before proceeding with #2. Three days ago I had the antibody test run to see if I had a response at all to the first shot. I did and it was fairly high, however, I was told that it doesn’t necessarily translate into dependable protection until I get the second shot. And, we won’t know how long that will last.
So if your husband isn’t registering any antibodies at this time, from my experience with lab results, I’m sorry to say he probably has no immunity. Maybe double check with the physician who had the titer run for your husband. He/she might have more input for you.
It really is disappointing that some of us who want the vaccine and would greatly benefit from the protection aren’t able get the immune response we need because of our medications. So, we just remain vigilant with Masks On! I like to think of them as deflector shields. 😉.