“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 whose 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.
Imperial’s findings were released as a pre-print paper, and have not yet been peer-reviewed.
Barclay said that the rapid waning of antibodies from infection did not necessarily have implications for the efficacy of vaccine candidates currently in clinical trials.
“A good vaccine may well be better than natural immunity,” she said.
(Reporting by Alistair Smout Editing by Bill Berkrot)