Watch: COVID immunity ‘could only last a few months’
It is unclear how long a COVID-19 vaccine will protect people from the virus, a scientist has warned.
Paul Elliott, professor of epidemiology and public health medicine at Imperial College London, said a coronavirus vaccine may only offer temporary immunity.
His comments came after trials of a vaccine developed by the University of Oxford found it produced an immune response in both young and old people.
On Tuesday, Imperial published a study revealing that levels of protective antibodies declined significantly after coronavirus infection.
Researchers said immunity is “waning quite rapidly” and that there is a risk of catching coronavirus multiple times.
Prof Elliott, director of the React antibody study, told BBC Radio 4’s Today programme that a vaccine response “may behave differently to the response to natural infection”.
Asked what the implications were for a vaccine and how long protection from a vaccine may last, he said: “I think that’s an open question that needs to be kept under close research and close scrutiny over the coming weeks and months.
“It’s possible that people might need booster vaccines. For some viruses there’s lifelong immunity; for the coronaviruses that doesn’t seem to be the case, and we know that the immunity can fluctuate so, yes, this is something that needs to be looked at very carefully.”
The study involved more than 365,000 randomly selected adults who tested themselves at home using a finger prick test between June and September to check if they had antibodies against COVID-19.
Over this period, the proportion of people who tested positive for antibodies declined by 26%, suggesting antibodies reduce in the weeks or months after a person is infected.
But Professor Wendy Barclay, who worked on the study, said there was still reason to be optimistic about a vaccine being able to stimulate longer-lasting protection.
She told Times Radio on Tuesday: “I think that we can still continue to be optimistic about vaccines because vaccines will work in a different way.
“What we’re measuring at the moment is the way that our bodies’ immune response reacts to the virus infecting us.
“But when we immunise with vaccines, particularly the new generation of vaccines that have been developed and put forward into trials for Sars-CoV-2, the virus that causes COVID, they work in quite different ways and they might make an immune response which is much more long lasting than natural infection.
“So we have to keep optimistic about that.”
Prof Elliott said healthcare workers were found to have higher levels of antibodies in the study, as did people living in large households and those from black, Asian and minority ethnic backgrounds.
The React study found that people aged 18 to 24 had the highest prevalence of antibodies and lowest decline in antibody levels, at 15%.
Meanwhile, people aged 75 and over had the lowest prevalence and saw the largest drop, with antibody levels falling by 39%.
Watch: What is the Job Support Scheme?
Coronavirus: what happened today
Click here to sign up to the latest news and information with our daily Catch-up newsletter