Immunity can vanish in months, study suggests
Coronavirus patients could lose immunity to the disease, new research suggests, indicating the virus which causes Covid-19 could continue to reinfect those who have had it in the past much like the common cold.
A UK study found that 60 per cent of people retained the “potent” level of antibodies required to resist future infections in the two weeks around the first sign of symptoms.
However, that proportion dropped to less than 17 per cent after three months, according to researchers at King’s College London.
Experts said the findings put “another nail in the coffin in the dangerous concept of herd immunity”, through which some had anticipated the public could build resistance through widespread exposure to Covid-19.
The study could also have implications for the effectiveness of some vaccine candidates.
Prof Stuart Neil, a co-author on the study, told The Guardian: “One thing we know about these coronaviruses is that people can get reinfected fairly often.
“What that must mean is that the protective immunity people generate doesn’t last very long.
“It looks like Sars-Cov-2, the virus that causes Covid-19, might be falling into that pattern as well.”
While the King’s College London research is yet to be peer-reviewed, it echoes findings in a study carried out by scientists at China’s Chongqing Medical University.
The Chinese research, which studied 37 symptomatic patients and 37 asymptomatic patients, found that of those who tested positive for the presence of the IgG antibody – one of the main types of antibodies induced after infection – over 90 per cent showed sharp declines in two to three months.
The median percentage decrease was more than 70 per cent for both symptomatic and asymptomatic patients.
Prof Jonathan Heeney, a virologist at the University of Cambridge, said there was a growing body of evidence that immunity Covid-19 is short-lived.
“Most importantly, it puts another nail in the coffin of the dangerous concept of herd immunity,” he said of the UK study.
Scientists working on a potential future vaccination to ward off the virus say an understanding of the level of immunity required to fight off the virus is vital to their work.
Professor Robin Shattock, who heads Imperial College London’s vaccine team, said 15 volunteers had been vaccinated so far, which will be ramped up to include another 200-300 participants in the “coming weeks”.
He told Sky News’ Sophy Ridge On Sunday: “I think it’s very difficult to predict. One of the things that we don’t understand right now is what level of immunity you need to prevent infection.
“If you only need a very small amount of immunity, I suspect most of the vaccines that are being developed will actually work, but if you need a very strong immune response or particular quality of immune response, we’ll see that actually it will be shaking out to some of these candidates.”
There are four coronavirus’ currently circulating among the human population – with the common cold among them.
Prof Stuart Neil, a co-author on the study, told The Guardian “One thing we know about these coronaviruses is that people can get reinfected fairly often.
“What that must mean is that the protective immunity people generate doesn’t last very long.
“It looks like Sars-Cov-2, the virus that causes Covid-19, might be falling into that pattern as well.”