Emerging evidence suggests that people infected with COVID-19 develop long-term immunity to the virus.
It turns out antibodies aren’t the only way to determine someone’s immune response to the virus. Scientists are now looking at memory T cells, a special type of white blood cell that identifies and destroys infected cells. And, as its name suggests, it “remembers” previous infections and can spur B cells to produce antibodies for a particular virus.
This means memory T cells’ response could prevent re-infection in people who’ve already had the virus.
Early studies were accurate in stating that antibodies fade within a few months of infection, but they assumed that fading antibodies meant a higher chance of reinfection. More recent studies reveal that the body’s immune response has more to its arsenal than previously thought.
One such study, “Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19,” was published in the medical journal Cell on August 14.
“Importantly, SARS-CoV-2-specific [COVID-19] T cells were detectable in antibody-seronegative exposed family members and convalescent individuals with a history of asymptomatic and mild COVID-19,” the authors write in their summary. “Our collective dataset shows that SARS-CoV-2 elicits robust, broad, and highly functional memory T cell responses, suggesting that natural exposure or infection may prevent recurrent episodes of severe COVID-19.”
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US, affirms that the study is indeed “good news” and that “there’s a lot of hot stuff going on right now [in T cell research].”
Equally exciting is evidence from a different study that people only exposed to—not infected with—COVID-19 can also produce T cells that recognize the virus.
As for exactly what “long-term” means in terms of immunity, the jury is still out. For T cells of SARS viruses, for example, memory T cells survive for decades.
In any case, a glimmer of hope for herd immunity is some good news we could all use right now.
Original Story appeared in Business Insider here.
Read the T cell study here.