Long-term immunity against coronavirus doubtful as antibodies fall rapidly

Grant Boone
October 29, 2020

The study gathered data from 365,000 randomly-selected adults who were administered at home three rounds of finger-prick tests for coronavirus antibodies between June 20 and September 28.

Antibodies are a key part of the body's immune defences and stop viruses from getting inside the body's cells.

The study, conducted by Imperial College London and published Tuesday, involved tests on more than 365,000 British people between June 20 and September 28.

"So although we are seeing a decline in the proportion of people who are testing positive, we still have a great majority of people who are unlikely to have been exposed".

Scientists at Imperial College London tracked antibody levels in the British population following the first wave of coronavirus infections, in March and April - and discovered they declined rapidly over the summer.

The rapid waning of antibodies did not necessarily have implications for the efficacy of vaccine candidates now in clinical trials, Imperial's Barclay said.

"Within the sickest sufferers with COVID-19, autoantibody manufacturing is frequent - a discovering with giant potential impression on each acute affected person care and an infection restoration", wrote Matthew Woodruff, an immunologist inside the Lowance Middle for Human Immunology at Emory College and co-author of the examine. But other experts said the researchers who conducted the study are known for their careful and meticulous work, and that the findings are not unexpected because other viral diseases also trigger autoantibodies.

More specifically, the study tested for detectable IgG antibodies.

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Research is still underway to determine how long antibodies are present after infection and if that presence provides immunity. But scientists involved cautioned that a great deal remains unknown about people's long-term antibody response to the virus.

The hope for long-term immunity from COVID-19 was thrown into doubt on Tuesday as a large United Kingdom study concluded that protective antibodies in people fall "quite rapidly" after a coronavirus infection.

"If antibodies stay high over a long period of time that is reassuring, it is not guaranteed [that you are immune to the virus] but it's reassuring", Dr Senanayake said. It remains unclear what level of immunity antibodies provide, or for how long this immunity lasts.

Scaled up to a nationwide level, it meant the proportion of the English population with antibodies dropped from 6.0 per cent to 4.4 per cent, according to the study.

"It is a very relevant study to understand the dynamics of the response to the virus, but we need to understand that the immune response is not based only on antibody".

"Just because an antibody level is declining doesn't automatically correlate with a lack of immunity, however you'd be happier if the levels didn't decline", he said.

This study has ominous implications for those who believe the pandemic can be brought to heel through herd immunity. "This study provides evidence that the level of immune response has declined over a relatively short period (three months) indicates that such future planning can not take for granted the beneficial effects of previous infection - importantly, should the results of this study prove robust, this implies that any strategy that relies on "herd immunity" lacks credibility".

Such results have delivered a blow to herd immunity - which, remember, is definitely not the government's real policy of dealing with the virus - due to fears over reinfection once recovery from coronavirus is complete.

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