COVID SCIENCE UPDATE

UK population with COVID-19 antibodies is shrinking

A new wave of coronavirus infections has been spreading in the UK, but the proportion of the population there with antibodies to the virus has been shrinking, potentially leaving more people vulnerable, new data show.

In a report posted on Tuesday on medRxiv ahead of peer review, scientists at Imperial College London say that while 6% of the population had COVID-19 antibodies around the end of June, that rate fell to just 4.4% in September.

Antibodies are not the body's only line of defense. Also important are immune cells called T cells and B cells that stimulate antibody production.

"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," said study coauthor Wendy Barclay in a news briefing.

World Health Organization spokesman Tarik Jasarevic said uncertainty over how long immunity would last and the fact most people had never had antibodies against this coronavirus shows 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 Geneva. -- Reuters