Researchers in the United Kingdom say they've observed a "significant" decline in the percentage of the population with COVID-19 antibodies, potentially pointing to "waning immunity."
Imperial College London scientists in the study found the prevalence of COVID-19 antibodies declined from six percent of the British population in June to 4.4 percent in September, Reuters reports. They came to the conclusion that there has been a "significant decline in the proportion of the population with detectable antibodies" by sending out finger-prick tests to a randomly selected group of over 365,000 people in England, according to CNN.
"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," Wendy Barclay, head of Imperial College London's Department of Infectious Disease, said, per Reuters.
The researchers were specifically looking for IgG antibodies in the study, and CNN notes that some other research has suggested "that other types of antibodies may persist longer than IgG does."
But Imperial College London's Helen Ward told BBC News the study suggests that "immunity is waning quite rapidly." Ward added in a statement, "We don't yet know whether this will leave these people at risk of reinfection with the virus that causes COVID-19, but it is essential that everyone continues to follow guidance to reduce the risk to themselves and others."