COVID-19 patients who have recovered still have significant immunity up to eight months after infection — a promising sign that there is lasting protection from the deadly illness, according to a new study.
The paper, published Wednesday in the journal Science, analyzed blood samples from 188 patients mostly from San Diego who had contracted the virus.
“There was a lot of concern originally that this virus might not induce much memory. Instead, the immune memory looks quite good,” co-author Shane Crotty, a researcher at the La Jolla Institute for Immunology, told MIT Technology Review.
Crotty and his team found that most patients had virus-specific antibodies in their bloodstream six months or more after infection.
But more importantly, they had robust levels of memory B cells, which create antibodies.
In some cases, they had more of these immune cells eight months after their infection than they did after only one.
If the person becomes infected again, the memory B cells could provide a blueprint on how to fight the virus even if they have low levels of antibodies.
The findings suggest that a person who has recovered may have immunity that lasts years.
Crotty said they will continue to track the participants in the study to see if they still have the same levels of B cell counts at 12 and 18 months after infection.
But despite the promising findings, Crotty reiterated that reinfection is still possible.
“Immunity varies from person to person, and uncommon individuals with weak immune memory still may be susceptible to reinfection,” he said.