Study suggests Covid-19 protection after infection may not be long lasting
It seems immunity declines at the same rate as antibodies decline, and that this is an indication of waning immunity at the population level
Alistair SmoutPicture: 123RF/LIGHTWISELondon — Antibodies against the novel coronavirus declined rapidly in the British population during the northern hemisphere summer, a study found 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 British population following the first wave of Covid-19 infections in March and April.Their study found that antibody prevalence fell by a quarter, from 6% of the population around the end of June to just 4.4% 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 that 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 healthcare workers, possibly due to repeated exposure to the virus.
The study backs up findings from similar surveys in Germany which 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.World Health Organisation spokesperson Tarik Jasarevic said that uncertainty over how long immunity would last and the fact most people had never had antibodies against the coronavirus in the first place showed the need to break transmission chains.
“Acquiring this collective immunity just by letting virus run through the population is not really an option,” he told a UN briefing in GenevaImperial’s study, based on a survey of 365,000 randomly selected adults, was released as a pre-print paper, and has not yet been peer-reviewed.
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. Read more: Business Day »
Private security will be present at Brackenfell High School as EFF vows to protest
Education MEC Debbie Schäfer said with the EFF granted permission to protest again outside the school, arrangements were made to ensure the matrics writing exams that morning could do so without disruption.
UK study finds evidence of waning antibody immunity to COVID-19 over timeAntibodies against the novel coronavirus declined rapidly in the British population during the summer, a study found on Tuesday, suggesting protection after infection may not be long lasting.
Severe Covid-19 symptoms may continue for 20 days, new study suggestsA review of dozens of studies by researchers at Oregon Health and Science University and Oregon State University suggests that people may shed virus for prolonged periods. _Lifestyle Where's the research?
Much of US Covid-19 relief depends on electionWho wins the presidency and which party controls the Senate will determine the economic reality
Europe prepares for tough times as Covid-19 surge forces new restrictionsGovernments have been desperate to avoid the lockdowns which shut down their entire economies at the start of the year, but the steady rise in new cases has forced them to ratchet up controls steadily.
KZN tavern shut down, owner fined R5 000 for flouting Covid-19 regulationsA Vryheid tavern owner was fined R5 000 and eight other popular drinking hot spots found themselves in trouble after they were found to be flouting Covid-19 regulations.
‘Cool heads’ absent as JSE investors worry about Covid-19Investors are awaiting unemployment and consumer inflation data during the week