U.K study finds sharp drop in COVID-19 antibodies just months after infection - SFGate

Imperial College London scientists found that in a random sample of 365,000 adults in the United Kingdom, the presence of COVID-19 antibodies declined in all age groups by 26% from June to September.

Younger people had higher levels than those over 65, and their antibodies lasted longer.

“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,” Barclay added.

Herd immunity occurs when enough of a population is immune to a disease, making it unlikely to spread and protecting the rest of the community.

If no vaccine is developed, the portion of the population that would have to recover from COVID-19 in order to achieve herd immunity is estimated at about 70%, or more than 200 million people in the United States, according to the Mayo Clinic.