Recovered COVID-19 patients still have significant immunity for up to eight months after infection, a promising sign that there is lasting protection against deadly disease, 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.
“Originally, there was a lot of concern that this virus could not induce much memory. Instead, immune memory looks pretty good, ”co-author Shane Crotty, a researcher at the La Jolla Institute of Immunology, told the 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 infection than just one.
If the person becomes infected again, memory B cells can provide a plan 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 for years.
Crotty said they will continue to monitor study participants to see if they still have the same levels of B-cell counts at 12 and 18 months after infection.
But despite promising conclusions, Crotty reiterated that reinfection is still possible.
“Immunity varies from person to person, and uncommon people with weak immune memory may still be susceptible to reinfection,” he said.