Long-term immunity against coronavirus doubtful as antibodies fall rapidly: Study

A person infected from novel coronavirus has a major chance of getting re-infected in just a few months or a year, a new UK-based study has claimed. As per the latest report by Imperial College London, the antibodies against COVID-19 wanes over time, which indicates that any level of immunity could last only a few months.

"Seasonal coronaviruses that circulate every winter and cause common colds can re-infect people after six to 12 months," said professor Wendy Barclay, a virologist who was one of the researchers on the study.

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

Scientists at Imperial College London have tracked antibody levels in 365,000 people following the first wave of COVID-19 infections in March and April. Their study found that antibody prevalence fell by a quarter, from 6 per cent of the population around the end of June to just 4.4 per cent in September.

The decline was largest in people aged 75 and above compared to younger people. Additionally, the decline in antibodies was also seen in asymptomatic people or people who didn't report a history of COVID-19. Patients whose COVID-19 infection was confirmed with a gold standard PCR test had a less pronounced decline in antibodies.

The study reported that those who didn't report a coronavirus history saw their antibodies drop 64 per cent. Those who came to know about coronavirus infection via lab testing saw their antibodies down by 22.3 per cent.

Interestingly, there was no change in the levels of antibodies in healthcare workers, possibly due to repeated exposure to the virus.

"This very large study has shown the proportion of people with detectable antibodies is falling over time. 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," said professor Helen Ward, one of the lead authors.Also read: Coronavirus update: New cases drop below 40,000 mark -- lowest since July 17Also read: COVID-19 patients' brains may age by 10 years: Imperial College study