The question of how long our bodies’ natural immunity against Covid-19 lasts after recovery has been puzzling scientists for quite some time. While many people claim to be “immune” to the disease because they’ve had it once, scientists have always maintained that this natural immunity can’t last forever – that’s just not how antibodies work. So, the question is – how long can it last?
The immune system is made up of different types of cells and molecules to fight disease. These include antibodies, T cells, and B cells. A recent study has found that Covid-19 antibodies as well as “memory” B cells and T cells can last as long as 6 to 8 months. This is two times better than previous estimates of the immunity lasting just 3 to 4 months.
The recent study involved a group of ~200 people who had recovered from Covid-19. Some had been infected up to eight months before the analysis. Other cases were more recent.
Of those that recovered, 95% still had immune system “memories” of the SARS-CoV-2 virus, which causes COVID-19.
The number and type of antibody proteins varied between the participants but nearly all of them were able to block the virus’s spike protein which allows it to infiltrate our cells. While the levels remained stable over time, they slightly decreased six to eight months after the infection.
“Several months ago, our studies showed that natural infection induced a strong response, and this study now shows that the responses last,” says Dr. Daniela Weiskopf at the La Jolla Institute for Immunology.
“We are hopeful that a similar pattern of responses lasting over time will also emerge for the vaccine-induced responses.”
What does this mean for us?
This is good news in the sense that this natural immunity can last for over half a year. On the other hand, it’s concerning that not all patients have such long-lasting immunity.
So, while the maximum possible longevity of the Covid-19 immunity is good news in and of itself, it’s not really something to go by as it’s not universal.
In addition, some Covid-19 strains such as the Brazilian P.1 virus can re-infect people by evading the body’s still-active natural immunities.
In light of all this news, the CDC’s general coronavirus guidelines for mask use, social distancing, and keeping good hygiene should probably still be maintained even by those who’ve recently recovered from the virus.