Most people who recover from Covid are immune to the disease for at least six months, a major Government-backed surveillance study suggests.
The UK Biobank study found high levels of Covid antibodies – virus-fighting proteins made by the body after vaccination or prior infection – in the blood of nine in 10 patients half a year or more after testing positive.
Almost all of participants (99 per cent) had the same high concentration of antibodies three months following their initial infection.
It comes on the back of a growing body of studies, including from Oxford University and Public Health England, which also pointed to months-long immunity after recovering from Covid.
Sir Patrick Vallance, England’s chief scientific adviser, said the latest project, which recruited over 20,000 volunteers, was ‘useful confirmation’ that survivors are protected for at least half a year – but exactly how long the Covid immunity lasts is still one of the burning questions of the pandemic.
The scientists behind the Biobank study said Covid survivors should still continue to follow the lockdown rules because 10 per cent won’t enjoy protection and it’s not clear if former patients can still carry and spread the virus.
Professor Sir Rory Collins, an epidemiologist at Oxford University who led the study, said: ‘One aspect of this is whether or not they can still carry the virus and whether they can pass it to other people.
‘But we still don’t know whether they can still be a transmitter and put others at risk. We still cant be sure that this provides complete protection although studies from Oxford show it provides at least some protection.’
Professor Collins and his team also estimate nine per cent of the British population has been infected with Covid, the equivalent of six million people, which is almost double the Government’s official tally of 3.8million.
Above are the levels of Covid-19 antibodies in the blood over time by age and ethnic group. They reveal the levels remain high for at least six months after infection. Scientists are testing whether this could continue for longer
The highest estimated immunity levels were in London and the lowest in Scotland. But no region was near ‘hear immunity’, when enough people in the community are protected against the virus to stop the virus spreading
The study also found only 43 per cent of cases suffered at least one of the three recognised Covid-19 symptoms. But 40 per cent did not have any of them, and 24 per cent of these were asymptomatic – meaning they had no symptoms
ONE SHOT OF PFIZER JAB MAY NOT BE ENOUGH TO PROTECT OVER-80S FROM COVID-19, STUDY FINDS
Delaying the second dose of the Pfizer coronavirus vaccine could leave some elderly patients at risk of catching the South African variant, research suggests.
Laboratory tests by Cambridge University found that a single shot of the jab might not stimulate a strong enough immune response to kill the new strain in over-80s.
Experts believe the E484K mutation on the South African variant’s spike protein, which it uses to bind to human cells, helps the strain ‘hide’ from the body’s natural defences.
Scientists reacting to the findings said now was ‘a good time to switch’ away from Britain’s one-dose strategy, which aims to get wider vaccine coverage quicker.
Ministers pivoted from their original plan to give people their second dose after 21 days after the country became engulfed in a devastating winter wave of the virus.
They pushed back the second dose for 12 weeks in a bid to give partial protection to as many vulnerable people as possible and drive down hospital admissions.
Already at least 105 Brits have been infected with the South African variant since December, which is likely to be an underestimate because Public Health England only looks at one in 10 random positive samples.
In another worrying development today, health chiefs revealed that mutation has now been found at least 11 times in different cases of people infected with the Kent variant, raising fears it could become a permanent feature of the British strain.
The UK Biobank study collected blood samples and information on potential symptoms from 20,200 participants for six months to the beginning of December.
They found over the study period the proportion of Britain’s population thought to have antibodies against the virus rose by two per cent from 6.6 per cent in May to 8.8 per cent by December.
It is thought to be even higher now as Department of Health data shows the second wave only peaked at the end of December before declining.
The levels were highest in London, at 12.4 per cent, the West Midlands, at 9.7 per cent, and North West, at 9.4 per cent.
They were lowest in Scotland, at 5.5 per cent, the South West, at 5.8 per cent, and Wales, at 5.9 per cent.
Younger people were more likely to have antibodies against the virus than those in older generations, at 13.5 per cent in the under 30s to 6.7 per cent in those over 70.
Those in the Black ethnic group were most likely to have protection against the virus, at 16.3 per cent, while it was lowest among the White group at 8.5 per cent and China at 7.5 per cent.
There was no difference in antibody levels between genders.
The study also found the three NHS earmarked symptoms of the virus only came up in 43 per cent of cases, while 24 per cent of other infections were asymptomatic – meaning there were no warning signs – and 40 per cent did not have the three main symptoms.
UK Biobank Chief Scientist, Professor Naomi Allen, said: ‘We are incredibly grateful to all the UK Biobank participants, and their children and grandchildren, who provided us with their blood samples for six months.
‘This important study has revealed that the vast majority of people retain detectable antibodies for at least six months after infection with the coronavirus.
‘Although we cannot be certain how this relates to immunity, the results suggest that people may be protected against subsequent infection for at least six months following natural infection. More prolonged follow-up will allow us to determine how long such protection is likely to last.’
Health Minister Lord Bethell, said: ‘This government-backed study provides further valuable insight into antibodies and increases our understanding of the virus, and I want to thank all of the talented researchers and everyone who volunteered to take part.
‘While the findings offer some promise, now is not the time for complacency. We still do not fully understand how long protection from antibodies may last, and we know people with antibodies may still be able to pass the virus on to others.
‘Right now, it remains vital for everyone to stay at home, even if you have had COVID-19 in the past, so we can stop the spread of the virus, protect the NHS and save lives.’
It comes after Public Health England also said that studies suggest immunity could last for six months after an infection
It comes after a Public Health England study published in November also said those that survive an infection could be protected against the virus for at least six months.
The findings may mean people who have already had the virus are less likely to get reinfected if they come into contact with the virus again.
A group of more than 2,000 people working for Public Health England volunteered to take part in the study and donate blood every month, with the first people recruited in early March, before lockdown was announced.
A total of 100 people tested positive for SARS-CoV-2, the virus which causes Covid-19, but none were hospitalised. More than half (56 per cent) had symptoms.
The study focused on a specific type of immune response, called T cells, which are created by the body following infection. They are different to antibodies but are just as pivotal in fighting disease.
The scientists behind the research call their findings encouraging and are ‘cautiously optimistic’ there is long-lasting and robust immunity following coronavirus infection.
The UK Coronavirus Immunology Consortium (UK-CIC) worked with PHE on the study and asked colleagues to be tested for the virus and take part in the study.
REVEALED: THE TRUTH ON COVID IMMUNITY, ANTIBODIES AND T CELLS
Antibodies are substances produced by the immune system which store memories of how to fight off a specific virus.
They come in different forms and may attack viruses and destroy them themselves, or may force the body to produce other kinds of immune cells and white blood cells to do the dirty work for them.
They can only be created if the body is exposed to the virus by getting infected for real, or through a vaccine or other type of specialist immune therapy.
Once antibodies have been created once – the body essentially moulds them around a virus when it encounters one in the blood – the body usually retains a memory of how to make them and which ones go with which virus.
Generally speaking, antibodies produce immunity to a virus because they are redeployed if it enters the body for a second time, defeating the bug faster than it can take hold and cause an illness.
Scientists are still unsure on the truth on immunity because Covid-19 has only been around since last January – meaning its long-term effects are still unclear.
So far cases of people getting infected more than once have not been numerous nor convincing.
With some illnesses such as chickenpox, the body can remember exactly how to destroy it and becomes able to fend it off before symptoms start if it gets back into the body. But it is so far unclear how long Covid-19 patients are protected for.
Evidence is beginning to suggest that antibodies disappear in as little as eight weeks after infection with the coronavirus, scientifically called SARS-Cov-2. But other studies show they can last for at least six months.
However, antibodies are only one type of substance that can produce immunity. The immune system is a huge web of proteins that have different functions to protect the body against infection.
T cells — which can’t be detected by the ‘have you had it’ antibody tests — made in response to the infection may offer a form of immunity that lasts several times longer.
T cells are a type of white blood cell that are a key component of the immune system and help fight off disease.
Other scientific studies have shown people who have had a common cold in the past two years have T cells that show ‘cross-reactive protection’ against Covid-19.