Question
Can I use an antibody test to check if the COVID vaccine worked?
19 April 2021. Related: All topics, COVID-19.
Hi. I had the Pfizer vaccine first shot 11 weeks ago and I just did a home test for COVID antibodies. This was the fingerpick test with a result in 20 minutes.
The result came back negative. Does that mean the vaccine hasn’t worked? Am I protected or not?
Answer
Hi
Antibody tests for diagnosis are different to antibody tests for vaccine response.
They test for different types of antibodies. So you can have full vaccine protection and still test negative on a diagnostic test.
Guidelines currently do not recommend testing for individual responses to the COVID vaccine. This is even in people who might be expected to have a lower response.
Even using the right test, scientists have not yet worked out a target level for immune responses to be protective.
They specifically advise not to used antibody tests as these are not likely to produce reliable results.
The negative result does not mean the vaccine did not work. The immune system is complex, and this test is not sensitive enough to show if you have protection.
This is one of more than 65 questions about COVID vaccines. It was produced by and for people living with HIV.
Q&A on COVID vaccines: are they safe and effective?
https://i-base.info/qa/16330
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