Tourists passing through London’s Underground Tube train at Victoria Station on September 23, 2020 during the ‘Hour Hour’ in the evening in central London, wearing a face mask due to the Covid-19 epidemic or covering the Wing-19 epidemic.
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LONDON – Antibodies to coronavirus are declining as people recover from the disease, according to the findings of a large UK study, a potential blow to those pushing for so-called herd immunity.
Researchers at Imperial College College London examined over 365,000 people in three rounds in England between 20 June and 28 September.
An analysis of finger-prick tests conducted at home found that the number of people with antibodies that could fight Covid-19 decreased by about 26% over the course of the study, rather than building up the immune system over time.
The RAACT-2 study, which has not yet been peer-reviewed, found that 6% of those tested had antibodies to the virus when the UK lockdown measures were relaxed during the summer. However, by the start of the second wave of cases last month, the figure has dropped to 4.4%.
“This very large study has shown that the proportion of people with detectable antibodies decreases over time,” said Helen W. Ward, a professor at Imperial College London and one of the authors of the study.
“We don’t yet know if this will put these people at risk of re-infection with the virus that causes COVID-19, but it is important that everyone continues to follow the guidelines to reduce the risk to themselves and others.”
What does it mean for herd immunity?
The findings suggest that population immunity levels may decline in the months following the first wave of coronavirus epidemics, potentially dampening the hopes of those calling for a controversial herd immune response strategy.
According to the Mayo Clinic, population immunity occurs when a sufficient population is immune to a disease, making it more likely to spread to the rest of the community and its potential. It can be achieved by natural infection – when enough people are exposed to the disease and develop antibodies against it – and by vaccination.
Health experts estimate that about 70% of the population will need to be vaccinated or will have natural antibodies to achieve herd immunity.
A man wearing a protective face mask takes refuge in the rain under an umbrella as he passes Chanzari Lane underground station in London on October 21, 2020, as the government considers lockdown measures to deal with an increase in novel Corovirus Covid-19 cases. .
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Some epidemiologists have suggested that targeting herd immunity would be a better response to an epidemic than a lockdown measure. Many, however, have harshly criticized a strategy that may require vulnerable people to be rescued at home when the virus spreads to young and healthy people.
Earlier this month, the top U.S. infectious disease specialist, Dr. Anthony Fawcett described calls to allow the U.S. population to spread the virus as “nonsense” and “dangerous.”
To date, more than .543. million people worldwide have been infected with coronavirus, including 1.16 million related deaths, according to data compiled by Johns Hopkins University.
Effects for refraction
The results of the RAACAT-2 study showed the following trend of antibodies not in health curves, but in people of all age groups and in all areas of the UK. The decline was greatest for people aged 75 and over, the study said, while the lowest decline was for people aged 18 to 24.
Researchers have found that the depletion of prevalent antibodies may be faster in the early stages than in the early stages. They warned that data on the matter was now coming out.
Only antibodies were measured in the study. The authors said that it is not clear whether the loss of antibody positivity is consistent with a person’s increased risk of relapse because it is not clear what T cell immune and memory reactions play in the protective immune system during re-exposure.
T cells are part of the immune system that protects against the specific disease of foreign pathogens.
To combat the rise in coronavirus cases in England, Prime Minister Boris Johnson announced that pubs and restrooms would be under curfew from 10 a.m. on Thursday.
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“Our study shows that the proportion of people who test positive for antibodies is declining over time,” said Professor Paul Elliott, director of real-time assessment of the community transmission program at Imperial and one of the authors of the study.
“A positive test for antibodies does not mean that you are immune to COVID-19. It is not clear what level of immunity antibodies provide, or how long this immunity lasts,” he added.
“If someone tests positive for antibodies, they need to follow national guidelines, including social distance measures. If there are symptoms, they have to take a swab test and wear a face mask where necessary.”
– CNBC Noah Higgins-Dunn Contributed to this report.
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