Long-term immunity to COVID-19? Cells found in recovered patients offer clues
It’s too early to understand if infection from the new coronavirus guarantees immunity from the disease in the long term, but new research points the scientific community in a positive direction.
A study revealed that recovered COVID-19 patients, and even those who have not been infected, have specific virus-fighting cells called T cells that target SARS-CoV-2 — the pathogen behind the pandemic — and may help them recover.
The discovery can aid in vaccine development, offer insight into pandemic control measures and contribute to the many unanswered questions surrounding potential long-term immunity to the new coronavirus.
The peer-reviewed paper was published Thursday in the journal Cell.
“People were really worried that COVID-19 doesn’t induce immunity, and reports about people getting re-infected reinforced these concerns, but knowing now that the average person makes a solid immune response should largely put those concerns to rest,” Shane Crotty, study co-author and immunologist at the La Jolla Institute of Immunology in California, said in a Medical Express article.
The team collected immune cells from 20 recovered COVID-19 patients who had mild cases and exposed them to coronavirus proteins, according to the non-profit research organization.
The researchers found that all the participants carried “helper T cells” that recognized the coronavirus “spike” protein, which helps the pathogen enter human cells, the institute said in the article.
This recognition is what spurs antibody production that helps people fight off anything foreign in the body such as viruses.
A separate response was also discovered.
Almost all patients produced “killer” T cells, which target and then destroy other cells infected with the virus, according to the researchers.
“Our data show that the virus induces what you would expect from a typical, successful antiviral response,” Crotty said in the Medical Express article.
However, the researchers caution that their results do not prove recovered patients will be immune from the virus in the future.
What’s more, after studying blood samples collected between 2015 and 2018 — before the pandemic began — the team discovered these individuals’ cells showed the same immune response to the virus when exposed to it in the lab, the institute wrote.
The researchers say this is likely because they were exposed to at least three of the four existing coronaviruses that cause the common cold or other respiratory illnesses.
“Most people get infected with one or more of these viruses at some point in their lives,” the Centers for Disease Control and Prevention said.
But the new coronavirus has only been circulating in humans for about five to six months, so more time and research is needed to determine if COVID-19 infection provides prolonged immunity, an epidemiologist wrote in April in The New York Times.
“Immunity after any infection can range from lifelong and complete to nearly nonexistent,” said Marc Lipsitch, a professor in the departments of epidemiology and immunology and infectious diseases at the Harvard T.H. Chan School of Public Health.
“So far, however, only the first glimmers of data are available about immunity to SARS-CoV-2.”
This story was originally published May 15, 2020 at 6:23 PM with the headline "Long-term immunity to COVID-19? Cells found in recovered patients offer clues."
