Although the research, published online in pre-print server bioRxiv, has not been peer-reviewed nor published in a scientific journal, the New York Times refers to it as "the most comprehensive and long-ranging study of immune memory to the coronavirus to date".
In this study, the team of researchers at the La Jolla Institute of Immunology in California, and the Icahn School of Medicine at Mount Sinai in NY, investigated multiple compartments of circulating immune memory to SARS-CoV-2 in 185 Covid-19 cases, including 41 cases more than six months post-infection.
While there are multiple vaccines against the coronavirus being studied, with two showing efficacy of preventing the virus of at least 90%, scientists have questioned how long the public would remain immune and if repeat vaccines would be necessary in order to keep the pandemic in check. Cases represented a range of asymptomatic, mild, moderate, and severe COVID-19 cases, including 41 cases at over 6 months post-infection. Other unknown areas include the roles and longevity of SARS-CoV-2-specific memory T cells; the location and function of tissue resident memory T cells; and whether preexisting immunity to SARS-CoV-2 via cross-reactive T cells helps protect against the virus or, rather, exacerbates harmful inflammation.More news: ⚡Check Out Few Instances When Lionel Messi Vented Anger in Public
Another recent study highlighted the importance of T cells response as they were detected in individuals who contracted SARS 17 years after the initial infection, according to the study.
But many immunologists have noted that it is natural for antibody levels to drop.
New research suggests that infectiousness peaks early in COVID-19 patients, highlighting the need to quickly identify and isolate cases before the virus spreads.
The virus could thus be "terminated fast enough that not only are you not experiencing any symptoms, but you are not infectious", added Dr Alessandro Sette, an immunologist and co-author of the study. "The spike IgG titers were durable, with modest declines in titers at six to eight months".More news: Gov. Gavin Newsom Issues New Stay-at-Home Order for Purple Tier Counties | KFI
Prof Lawrence Young, from the University of Warwick, said: "The significant take home message is that the immune response to the virus is more long-lived than previously thought".
Speaking on BBC Radio 4's Today programme, he said: "We're really looking globally, we want to be able to get to every corner of the world if indeed the vaccine is shown to work". The new study, she said, bolsters her belief that even small amounts of these memory cells could provide long-term immunity.
"I don't think it's an unreasonable prediction to think that these immune memory components would last for years", he said.
Scientists looked at immune cells in survivors of Covid-19, including those that store "memory" of the virus which can activate antibodies.More news: Tokyo reports record daily virus cases, outbreak locks down Australian state