After recovering from a long bout of COVID-19-like symptoms, my girlfriend, Mary, tested positive for antibodies. But when she underwent a second antibody test a month or so later, she tested negative.
What do you think this means? Is it possible she initially had antibodies, but now they’ve faded? I’ve read and heard a lot of accounts of coronavirus antibodies rapidly disappearing — and leaving people prone to reinfection.
Dr. Prescott Prescribes
The most likely explanation is that Mary’s first antibody test was inaccurate. Antibody testing has been plagued by false positives, which is why the Food and Drug Administration has made a list of more than 80 antibody tests (technically known as serology tests) that should no longer be used. I believe the test that Mary first took is on that list.
It’s also possible that the first positive test was correct and the second negative one was wrong. However, false negatives (when you have antibodies, but the test says you don’t) have proven rare.
It is true that research studies have recently reported that antibody levels declined two to three months following infection. But a drop in antibodies is perfectly normal after an acute infection subsides.
It’s important to understand that antibodies don’t serve as the only form of protection against pathogens like viruses. The immune system also has other components — most notably, T and B cells — that provide long-term defenses against future infection.
The news has carried multiple accounts of patients who believe they’ve been reinfected after recovering from initial bouts of the virus. However, to date, researchers have not been able to document any such cases.
Obviously, we’re still learning about the coronavirus, but if it behaves like other viruses, it’s quite possible these patients remained infected even when they’d believed they’d recovered. Thus, the “reinfection” may, in actuality, have been the continuation of an infection that never truly went away. This theory is buttressed by the fact that we now know the virus can linger in our bodies for periods of up to several months.
Like all of us, Mary should remain vigilant. That means — yup, I’m going to say it again — mask-wearing, physical distancing and hand-washing.