Two studies published last week offer insight into how long we might have immunity to COVID-19 after infection.
Most people who become infected with the coronavirus produce antibodies to fight it. But these new studies show many patients lose much of their long-term immunity from those antibodies within weeks or months after recovery.
One study, published on the preprint server medRxiv, found that 10 percent of COVID-positive patients registered undetectable antibody levels within weeks of first showing symptoms.
In the other study, published in the journal Nature Medicine, researchers found that asymptomatic individuals with COVID-19 reacted less strongly to infection. 40 percent had undetectable levels of protective antibodies two to three months after the infection.
While these results are thought-provoking, more research is needed, following large numbers of infected people over time to truly know how many people produce antibodies when infected with coronavirus, and for how long.
There have been many reports of recovered patients who never raised an antibody response at all, so it’s not yet clear how they cleared the virus. It’s possible that a larger percentage of the population than we realize might already be protected to some degree from the coronavirus. But, it’s also possible that almost everyone is still vulnerable and we just haven’t seen the virus run through most of the population yet.
It seems, based on this research, that each of us produce a different antibody response to this virus, complicating not only recommendations for current patients, but also developing a vaccine that works equally well for everyone.