The longitudinal study, published recently on Cell Reports Medicine, looked at 254 patients with mostly mild to moderate symptoms of SARS-CoV-2 infection over a period for more than eight months (250 days) and found that their immune response to the virus remained durable and strong.
In following the patients for months, researchers got a more nuanced view of how the immune system responds to COVID-19 infection. The picture that emerges indicates that the body’s defense shield not only produces an array of neutralizing antibodies but activates certain T and B cells to establish immune memory, offering more sustained defenses against reinfection.
“We saw that antibody responses, especially IgG antibodies, were not only durable in the vast majority of patients but decayed at a slower rate than previously estimated, which suggests that patients are generating longer-lived plasma cells that can neutralize the SARS-CoV-2 spike protein.”
Ahmed says investigators were surprised to see that convalescent participants also displayed increased immunity against common human coronaviruses as well as SARS-CoV-1, a close relative of the current coronavirus. The study suggests that patients who survived COVID-19 are likely to also possess protective immunity even against some SARS-CoV-2 variants.