LONDON (UK) – A study conducted by healthcare workers in Britain has found that people who have had coronavirus are likely to have immunity to it for at least five months. However, there is evidence that those with antibodies may still be in a position to carry and spread the virus.
According to preliminary findings by scientists at Public Health England (PHE), a second round of infections in people who have COVID-19 antibodies from a previous infection is rare. Only as many as 44 cases were detected among 6,614 people who had the infection before, as per the study.
Scientists warned that the findings mean those who were infected in the first wave of the pandemic could be vulnerable now.
Experts also said those with so-called natural immunity, which is acquired through having had the infection, may still carry the virus in their nose and throat and could pass it on.
“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts,” said co-leader of the study Susan Hopkins, who is also the senior medical adviser at PHE, on Thursday.
“This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections. But there is still a risk you could acquire an infection and transmit (it) to others.”
Experts who are not directly linked to the study, which is known as the SIREN research, urged people to make a note of its main findings.
“These data reinforce the message that, for the time being, everyone is a potential source of infection for others and should behave accordingly,” said Eleanor Riley, a professor of immunology and infectious disease at Edinburgh University.
The research has “major implications for how we can get out of the current crisis”, said Simon Clarke, associate professor in cellular microbiology at Reading University.
“This means that the vast majority of the population will either need to have natural immunity or have been immunised for us to fully lift restrictions on our lives, unless we are prepared to see many more people being infected and dying from COVID-19,” he said.
The research has not been able to monitor antibody or other immune responses to the vaccines being rolled out in the country, said PHE in a statement, adding that effects of the shots would be studied in detail later this year.
The study involves tens of thousands of healthcare workers in the country who have been screened regularly since June.