LONDON (Reuters) – A small but important UK study found that “cellular immunity” to the pandemic SARS-CoV-2 virus is present after six months in people who have mild or asymptomatic COVID-19. Was, suggesting that they may have some level of protection, at least for the time.
Scientists who presented findings from 100 non-hospitalized COVID-19 patients in the UK said they were “convinced”, but that did not mean that people could not be twice infected with the disease in rare cases.
“While our findings are cautiously optimistic about the strength and length of immunity generated after SARS-CoV-2 infection, this is just one piece of the puzzle,” said Paul Moss, a professor of hematology at the University of Birmingham, UK Which hinder co-study.
“We still have a lot to learn, before we know how COVID-19 works, we have a complete understanding of it.”
Experts not directly involved in the study said its findings were important and would add COVID-19 to a growing body of knowledge about potential protective immunity.
The study, which has not yet been peer-reviewed by other experts, but was published online on Biorevix, analyzed the blood of 100 patients six months later, as they had mild or asymptomatic COVID-19. It was found that while some patients’ antibody levels had fallen, their T-cell response – another important part of the immune system – remained strong.
“(Our) preliminary results suggest that T-cell responses may abolish the initial antibody response,” said Sharm Ladani, a consultant epidemiologist at Public Health England, who co-led the work.
The study also found that the size of the T-cell response varied, and was significantly higher in those with symptoms of COVID-19, who had no symptoms when infected.
Researchers said this can be interpreted in two ways: It is possible that high cellular immunity may provide better protection against re-infection in people who have had symptoms, or equally, asymptomatic patients may be better protected from the virus. Are able to fight which produce a large immune response without the need.
“These results provide assurance that, although SARS-CoV-2 antibody titrations may fall below detectable levels within a few months of infection, a degree of immunity to the virus can be maintained,” Charles Bangam, chair of immunology Imperial College London.
“It’s a long-term fix in terms of both vaccination and the possibility of long-term protection against re-infection,” said Eleanor Riley, an immunology and infectious disease specialist at Edinburgh University. However, he stressed that “we do not yet know whether the people in this study are safe from re-infection.”
While more than 46 million people worldwide are infected with COVID-19, confirmed cases of re-infection are very rare so far.
Reporting by Kate Kelland, edited by Steve Orlofsky and Nick McPhee