Reader bemoans lack of precise post-vaccine testing

DEAR DR. ROACH >>

Can you comment on the lack of a test that truly demonstrates the effective level of immunity an individual has from receiving the COVID vaccine? My wife has lupus and rheumatoid arthritis, and had both doses of the Pfizer vaccine over a month ago. Now we learn that her immune system may not have created any antibodies against COVID-19! There is no test to give her peace of mind that she is protected. The one test mentioned (SARS-CoV-2 SemiQuantitative Total Antibody, Spike) shows only that you have some antibodies from the vaccine, but doesn’t reveal the true level of protection. It’s frustrating! — B.W.

I completely agree that the lack of a blood test that can reliably identify people who are at risk for developing COVID-19 — or alternatively, those who have reliable protection — is extremely frustrating. For many vaccines, we do have such a test for effectiveness. For measles or rubella, for example, a person can get the blood test, and if the antibody isn’t present at a high-enough level, we know they are at risk and recommend booster shots. Unfortunately, we do not have that test for COVID-19 at the time of this writing.

There are many different kinds of antibody tests a physician can order, but it is unknown whether the absence of antibodies indicates a person is at risk, nor whether their presence is reliable proof of immunity.

The Centers for Disease Control and Prevention notes: “none of the currently authorized tests have been authorized to assess individuals that have received a vaccine” and “antibody testing is not currently recommended to assess for immunity to COVID-19 following COVID-19 vaccination or to assess the need for vaccination in an unvaccinated person.” I sincerely hope that by the time this column is published or shortly thereafter, we will have a reliable test.

This would be very useful, especially for people such as your wife, who are at higher risk for complications of COVID-19 and who have a reduced response to the vaccine due to medications she might be taking for her lupus and rheumatoid arthritis.