Sunday, August 16, 2020

CDC finally revealed how long coronavirus immunity lasts – and it looks like bad news

A man wears a coronavirus face mask while taking public transportation and looking out a train window. Image source: Maria Sbytova/Adobe

By Chris Smith

How long does novel coronavirus immunity last? That’s a question health officials can’t answer for certain since COVID-19 hasn’t existed for long enough to tell. But it’s an answer we need not just for vaccine development, but also for the next stages of pandemic management. How long is a COVID-19 survivor protected for? How bad would a second COVID-19 bout be for people who already had it?

Scientists initially said that coronavirus immunity might match the immunity we get from the other human coronaviruses that cause common colds. That’s anywhere from six to 12 months, and that’s how long we expect vaccines to last as well. Recent data showed that neutralizing antibodies may disappear from the bloodstream within three months, but the immune system also has backup T cells that can kill the virus upon reinfection by kickstarting the production of antibodies. Those cells live longer than antibodies, though it’s unclear how long their lifespan is. It’s also believed that exposure to human coronaviruses that cause common colds provides some protection against the virus.

Health authorities have not actually offered a clearly defined period for coronavirus immunity, because there’s not enough scientific data to back any of it up. That recently changed though, when the CDC quietly updated one of its main guidelines with information that explicitly mentions a COVID-19 immunity timeframe.  Read more >>