LONDON (Reuters) – People with COVID-19 are more likely to be immune to it for at least five months, but there is evidence that people with antibodies can still carry and spread the virus, a study in the UK by to health workers. has found.
Preliminary findings from Public Health England (PHE) scientists showed that reinfections in people who have COVID-19 antibodies from a past infection are rare, with only 44 cases found among 6,614 people previously infected in the study.
But experts warned that the findings mean that now people who contracted the disease during the first wave of the pandemic during the early months of 2020 could be vulnerable to catching it again.
They also warned that people with so-called “natural immunity,” acquired from having the infection, could still carry the SARS-CoV-2 coronavirus in their nose and throat and could inadvertently transmit it.
“We now know that most of those who have had the virus and developed antibodies are protected against reinfection, but that’s not total and we still don’t know how long the protection lasts,” said Susan Hopkins, senior PHE medical advisor and co- study leader, whose findings were released Thursday.
“This means that even if you think you already have the disease and are protected, you can be reassured that you are very unlikely to develop serious infections. But there is still the risk that he could acquire an infection and pass it on to others. “
A statement on the study said its results did not address antibodies or other immune responses to vaccines being deployed against COVID-19 or the effectiveness of vaccines. The response to vaccines will be considered later this year, he said.
The research, known as the SIREN study, involves tens of thousands of healthcare workers in Britain who have been tested regularly since June to detect new COVID-19 infections and the presence of antibodies.
Between June 18 and November 24, the scientists detected 44 possible reinfections, two “likely” and 42 “possible,” from 6,614 participants who had tested positive for antibodies. That said, this represents 83% protection against reinfection.
The researchers plan to continue monitoring and evaluating participants to see if this natural immunity can last more than five months in some. But they warned that early evidence from the next stage of the study already suggests that some people with immunity may carry high levels of the virus and transmit it to others.
“Therefore, it is crucial that everyone follows the rules and stays at home, even if they have previously had COVID-19,” they said in the statement about their findings.
Reports by Kate Kelland; Edited by Mark Heinrich