By Alistair Smoot
LONDON (Reuters) – Antibodies to the new coronavirus are declining rapidly among the British population over the summer, according to a study on Tuesday, which suggests that protection against infection may be short-lived and raises the prospect of weakened community immunity.
Researchers at Imperial College London tracked antibody levels in the British population after the first wave of COVID-19 infections in March and April.
Their study found that antibody prevalence dropped from 6% of the population around the end of June to just 4.4% in September. This raises the prospect of declining population immunity before the second wave of infections, which has imposed local blockages and restrictions in recent weeks.
Although immunity to the new coronavirus is a complex and murky area and can be aided by T cells as well as B cells, which can stimulate the rapid production of antibodies after re-exposure to the virus, researchers say that experience with other coronaviruses suggests that immunity may not be permanent.
“We can see the antibodies and reduce them, and we know that the antibodies themselves are quite protective,”
“Regarding the evidence, I would say that from what we know about other coronaviruses, it appears that immunity decreases at the same rate as antibodies, and that this is an indication of declining immunity at the population level.”
Those whose COVID-19 was confirmed by the gold standard PCR test had a less pronounced decrease in antibodies than people who were asymptomatic and unaware of their initial infection.
There were no changes in antibody levels observed in healthcare professionals, probably due to repeated exposure to the virus.
Imperial’s findings have been published as pre-printed paper and have not yet been reviewed.
Barclay said the rapid attenuation of antibodies from infection does not necessarily have implications for the efficacy of vaccine applicants currently in clinical trials.
“A good vaccine can be better than natural immunity,” she said.
(Report by Alistair Smoot; Edited by Bill Bercrot)