Source: MSN/The Wall Street Journal
LONDONA large English study showed the number of people with Covid-19 antibodies declined significantly over the summer, suggesting that getting the virus may not confer long-lasting immunity from future infection.
The survey of 365,000 adults in England who tested themselves at home using a finger-prick test showed the proportion of people testing positive for Covid-19 antibodies declined by 26.5% between June 2012 weeks after the peak of infections in the countryand Sept. 28.
The results also suggested that people who didnt display symptoms were likely to lose detectable antibodies before those who had showed symptoms. The study, conducted by Imperial College London and the Ipsos Mori polling organization, was funded by the British government, which announced the results and published the study on Monday night. The results havent yet been reviewed by other experts.
Doctors dont yet know whether antibodies confer any effective immunity against reinfection by Covid-19. But even if they do and the results of this survey are confirmed, it suggests the prospect of widespread long-term herd immunity to the virus will be difficult to achieve. Herd immunity occurs when enough people in a population develop an immune response, either through previous infection or vaccination, so that the virus cant spread easily and even those who arent immune have protection.
Findings showed 18-24 year olds lost antibodies at a slower rate than persons aged 75 and over. The smallest decline of 14.9% was of people aged between 18 and 24 years, and the largest decline of 29% was of people aged 75 and over.
The study reflects earlier smaller trials and suggests that antibodies to the virus decline over 6-12 months after infection, as in other seasonal coronaviruses such as the common cold. The study doesnt indicate whether other types of immune responsessuch as that contributed by so-called T cellswould help protect against reinfection.
– Read Also: ‘Covid: Antibodies ‘fall rapidly after infection,’ BBC News, Oct. 26, 2020
– Y-shaped antibodies stick to the surface of viruses to stop them infecting the body’s cells.