My mother is immune-compromised. She is fully vaccinated. She (and her doctor) is curious about what level of protection she now has.
She took a COVID antibody test. It was negative. Moreover, she and her doctor later learned that there IS no accepted test for checking post-vaccination COVID antibodies.
OK. Fair enough. Sources like this and this point out that the antibody tests are actually sort of new, also operate under Emergency Use Authorizations, and may not detect the antibodies produced by vaccines (instead, they may only find antibodies produced by an infection).
So why and how are researchers using these very tests to check for antibodies post-vaccination? Not only the primary studies of vaccine effectiveness/longevity, but also ones like this about vaccinated mothers passing antibodies on to their newborns.
So … are these tests useful for looking at antibodies post-vaccination, or not?
Antibody tests are done using antigens, the things antibodies react with. A viral infection typically produces multiple antibodies, that react to multiple antigen sites on the virus.
A mRNA vaccination produces antibodies only to (a) the spike protein, if its a ‘spike protein’ mRNA vaccine, or (b) the subunit, if it’s Receptor Binding Domain mRNA vaccine.
An antibody test may test using several specific antigens. If they aren’t the specific antigens reactive to antibodies produced in reaction to the vaccine, the test will show nothing.
Antibody research may test using any antigens, or may have some other method of detecting antibodies, or may be research using antibodies to test for antigens – which is the opposite of an antibody test using antigens to test for antibodies.
I’m confused by your question. There are antibody tests that test for antibodies that you’d get if you were vaccinated. (Antibodies to the spike protein.) There are also antibody tests that test for antibodies that you’d get from recovering from covid but wouldn’t get from being vaccinated. (Antibodies to the shell of the virus.)
All of these are only approved under an EUA, but they work pretty well.
I think the confusion is because the CDC, in it’s infinite wisdom, is advising against the testing your mom did. That’s not because the tests don’t detect antibodies fairly reliably. It’s because the correlation between antibody levels and protection isn’t well understood.
That being said, honestly, I’d be worried for your mom.
The antibody tests aren’t useful… yet. With more information, they might be. And we get that more information by… using them in research.
There are antibody tests that test for antibodies that you’d get if you were vaccinated. (Antibodies to the spike protein.) There are also antibody tests that test for antibodies that you’d get from recovering from covid but wouldn’t get from being vaccinated. (Antibodies to the shell of the virus.)
Ah. I wasn’t aware that there were vaccine-antibody tests that the pharma researchers were using for their purposes that were different from the tests people were using to check for infection.
I remember @puzzlegal mentioning that they also test for both types of antibodies when you donate blood.
The Red Cross stopped doing that a couple of month ago. But yes, they did.
It was my understanding that the testing for antibodies in immunocompromised people is different than for others. I had asked my coordinator a few months ago about it and they were not offering them for us, and was told a “drug store kit” or even going to my PCP for a test would be a waste of money.
I was offered a place in a trial group for possible boosters; however, it was explicitly stated when boosters were allowed we would need to remain in the trial and go by their timeframe. I passed.