Antibodies wane rapidly after infection: Study

A research team at The Imperial College London found out that the number of people testing positive for antibodies has decreased by 26% between June and September. There seems to be a risk of catching the virus multiple times since immunity appears to wane “quite rapidly”.

According a BBC Health report, more than 350,000 people in England have taken an antibody test as part of the REACT-2 study so far. Researchers found delectable antibodies in 60 people out 1000 in the first round of testing which happened during June and July. However, the latest set of tests that happened in September showed a fall in this number down to 44 out of 1000.  It proves that the number of people with antibodies fell by more than a quarter.

“Immunity is waning quite rapidly, we’re only three months after our first [round of tests] and we’re already showing a 26% decline in antibodies,” Prof Helen Ward, one of the researchers at The Imperial College London told BBC. This fall was seen be greater amongst those over 65, younger age groups and asymptomatic cases, as compared to full-blown COVID-19.

It has also been observed that regular exposure to virus might also be the reason for relatively high antibodies found in healthcare workers.

“We can see the antibodies and we can see them declining and we know antibodies on their own are quite protective. On the balance of evidence, I would say 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,” Prof Wendy Barclay told BBC.

While there are a few confirmed cases of people getting coronavirus twice, the hope is the second infection will be milder than the first, even if immunity does decline, as the body should have an “immune memory” of the first encounter and know how to fight back.

One of the researchers, Prof Graham Cooke told BBC that “The big picture is after the first wave, the great majority of the country didn’t have evidence of protective immunity. The need for a vaccine is still very large, the data doesn’t change that.”

Professor Paul Elliott, director of the REACT-2 study, said it would be wrong to draw firm conclusions from the study about the impact of a vaccine. “The vaccine response may behave differently to the response to natural infection”, he told BBC. “Some people might need follow-up booster doses of any vaccine that became available to top up fading immunity over time”, he added.