CORONAVIRUS immunity could last for only six months and see Brits forced to get yearly vaccine injections.
New research has cast doubt over proposals to introduce immunity passports, which would allow people who have had Covid-19 to socialise and return to work.
⚠️ Read our coronavirus live blog for the latest news & updates
Scientists at the University of Amsterdam found that immunity from other coronavirus diseases sometimes lasted for just half a year.
The study looked followed ten men for 35 years, testing them regularly for four coronaviruses that cause the common cold.
Researchers concluded that there was “an alarmingly short duration of protective immunity.”
They added: “We saw frequent reinfections at 12 months post-infection and substantial reduction in antibody levels as soon as six months post-infection”.
The findings suggest that Brits could need a yearly dose of the vaccine to ensure they are immune.
The study has cast fresh doubt over the introduction of immunity passports, which would see Brits who have caught the virus allowed to return to normal life.
Matt Hancock said on Thursday that the government was working on “systems of certification” for people to show that they have had the virus.
It is thought that people who recover from coronavirus have some protection from getting it again, but the amount of time the immunity lasts is currently unknown.
Professor Lia van der Hoek, a researcher involved in the University of Amsterdam’s study, told The Times: “Herd immunity is an issue, even with vaccination, as it may be that people can get an infection within six to 12 months.
“It is, however, uncertain what kind of disease is associated with a reinfection by Sars-CoV-2, that is of course a big uncertainty.”
It comes as Oxford University began testing its vaccine on more than 10,000 people.
Scientists are starting the second phase of their coronavirus vaccine trials, giving it to children and over 70s.
The first phase of the University of Oxford trial began in April, involving 1,000 adults aged 55 and under.
The age range of participants has now been expanded to include those aged 56-69, 5-12 and over 70s.
This phase could take between two to six months, depending on how many people are exposed to the virus.
Sarah Gilbert, professor of vaccinology at the Jenner Institute, told the BBC: “We have had a lot of interest already from people over the age of 55 years who were not eligible to take part in the phase-one study.
most read in uk news
CORONAVIRUS CRISIS - STAY IN THE KNOW
Don't miss the latest news and figures - and essential advice for you and your family.
To receive The Sun's Coronavirus newsletter in your inbox every tea time, sign up here.
To follow us on Facebook, simply 'Like' our Coronavirus page.
Get Britain's best-selling newspaper delivered to your smartphone or tablet each day - find out more.
“And we will now be able to include older age groups to continue the vaccine assessment.
“We will also be including more study sites, in different parts of the country.”
The Oxford researchers are still looking for volunteers to take part in the second phase of the trial.