Thomson Reuters · Posted: Oct 27, 2020   
      
   Scientists find signs of waning antibody immunity to COVID-19 over time in   
   England   
      
      
   Antibodies against the novel coronavirus declined rapidly in the population in   
   England during the summer, according to a preprint posted on Tuesday,   
   suggesting protection after infection may not be long-lasting and raising the   
   prospect of waning immunity    
   in the community.   
      
   Scientists at Imperial College London have tracked antibody levels in the   
   population in England following the first wave of COVID-19 infections in March   
   and April.   
      
   Their study found that antibody prevalence fell by a quarter, from six per   
   cent of the population around the end of June to just 4.4 per cent in   
   September. That raises the prospect of decreasing population immunity ahead of   
   a second wave of infections in    
   recent weeks that has forced local lockdowns and restrictions.   
      
   Although immunity to the novel coronavirus is a complex and murky area, and   
   may be assisted by T cells as well as B cells, which can stimulate the quick   
   production of antibodies following re-exposure to the virus, the researchers   
   said the experience of    
   other coronaviruses suggested immunity might not be enduring.   
      
   "We can see the antibodies and we can see them declining and we know that   
   antibodies on their own are quite protective," Wendy Barclay, head of the   
   Department of Infectious Disease at Imperial College London, told reporters.   
      
   "On the balance of evidence I would say, with what we know for other   
   coronaviruses, it would look as if immunity declines away at the same rate as   
   antibodies decline away, and that this is an indication of waning immunity at   
   the population level."   
      
   Those for whom COVID-19 was confirmed with a gold standard PCR test had a less   
   pronounced decline in antibodies, compared to people who had been asymptomatic   
   and unaware of their original infection.   
      
   There was no change in the levels of antibodies seen in health-care workers,   
   possibly due to repeated exposure to the virus.   
      
      
   Vaccine may be more protective   
      
   The study, which has not yet been peer reviewed to flag flaws, backs up   
   findings from similar surveys in Germany. The German researchers found the   
   vast majority of people didn't have COVID-19 antibodies, even in hotspots for   
   the disease, and that    
   antibodies might fade in those who do.   
   - - -   
   "Acquiring this collective immunity just by letting the virus run through the   
   population is not really an option," he told a UN briefing in Geneva.   
      
   Imperial's study was based on a survey of 365,000 randomly selected adults.   
      
   The rapid waning of antibodies did not necessarily have implications for the   
   efficacy of vaccine candidates currently in clinical trials, Imperial's   
   Barclay said.   
      
   "A good vaccine may well be better than natural immunity," she said.   
      
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