Study: Protective immunity against novel coronavirus may last for over 8 months
By: Team Ifairer | Posted: 08-01-2021
Heart It
COVID-19 survivors may have protective immunity against serious disease from the SARS-CoV-2 virus for months, or even years after the infection, a study suggests. The findings, based on analyses of blood samples from 188 COVID-19 patients, suggest that nearly all survivors of the disease have the immune cells necessary to fight re-infection. "Our data suggest that the immune response is there -- and it stays," Professor Alessandro Sette from La Jolla Institute for Immunology in the US.
The researchers measured antibodies, memory B cells, helper T cells and killer T cells - all four components of immune memory -- at the same time. The study, published in the journal Science, helps clarify some concerning data from other institutes, which showed a dramatic drop-off of COVID-fighting antibodies in the months following infection.
Some feared that this decline in antibodies meant that the body wouldn't be equipped to defend itself against reinfection. Sette explained that a decline in antibodies is very normal. "Of course, the immune response decreases over time to a certain extent, but that's normal," he noted. "That's what immune responses do. They have a first phase of ramping up, and after that fantastic expansion, eventually the immune response contracts somewhat and gets to a steady state," Sette added.
The researchers found that virus-specific antibodies do persist in the bloodstream months after infection. They said the body also has immune cells called memory B cells at the ready, adding that if a person encounters SARS-CoV-2 again, these cells could reactivate and produce antibodies to fight re-infection. The SARS-CoV-2 virus uses its "spike" protein to initiate infection of human cells, so the researchers looked for memory B cells specific for the SARS-CoV-2 spike.