Covid England: 1 in 7 had coronavirus antibodies in mid-January

One in seven people in England had coronavirus antibodies in mid-January – including 21% of London, surveillance study reveals

  • The Office for National Statistics (ONS) tested the blood of more than 1,300 people across the country 
  • The mass surveillance scheme found 15.3% tested positive for antibodies — up from 10% in December
  • The presence of antibodies in the blood generally means someone has either partial or total immunity 
  • Antibodies can only be made by coming into contact with the coronavirus, or by getting vaccinated


Around one in seven people in England — the equivalent of 8.6million — had coronavirus antibodies by mid-January, a major surveillance study revealed today.

The Office for National Statistics (ONS) tested the blood of more than 1,300 people across the country and found 15.3 per cent tested positive for antibodies — up from 10 per cent in December. The proportion was as high as 21 per cent in London. 

Antibodies are substances made by the immune system in response to infection or vaccinations which defend against viruses. The presence of them in the blood generally means someone has either partial or total immunity against catching a disease again.  

But the figures could easily be an under-estimate because antibody levels fade over time and some people won’t ever develop any. Scientists believe most people have high levels of antibodies for six months after an infection but to what extend they fade after then remains a mystery because there has not been a long enough time to follow up. 

The true size of the pandemic is a mystery because millions of infected people were not tested during the height of the crisis last spring. If the ONS results are accurate, it would suggest Covid has an infection-fatality rate (IFR) of around 1.26 per cent, given there have been around 110,000 lab-confirmed deaths since the pandemic began. 

No10’s top scientific advisers believe the mortality rate is closer to the 0.5 per cent mark, suggesting that around 22million people — or almost 40 per cent of England’s population — have already had the virus. 

Meanwhile, there are also questions about whether previous infection from an older strain of Covid fully protects people from catching or falling ill with new variants of the virus.

It appears as though former patients are immune to the Kent strain, based on vaccine studies which show the current crop of jabs work fine in neutralising that variant. But scientists are more concerned about strains that emerged in South Africa and Brazil, which are at least somewhat antibody resistant and make vaccines less potent.

It’s thought Covid survivors will still enjoy strong protection against those variants because antibodies are only one part of a larger immune response to Covid, which also involves crucial white blood cells.  However, there have been confirmed reports of a handful of health workers in Brazil becoming sick with the new variant there months after recovering from the original strain. 

The ONS’s survey, which collects regular blood samples from a group of people intended to represent England’s population, suggested that signs of immunity are strongest in London, where antibodies were found in 21 per cent of people.

The West Midlands saw the second highest past rate (18.8 per cent), followed by Yorkshire and the Humber (18.7 per cent). Six out of nine regions had levels higher than the England average, with only the South East, South West and East of England showing lower signs of immunity than the country as a whole.

The figures are different to estimates made by Cambridge University experts, who also feed into SAGE. Last month the team estimated the attack rate — the proportion of how many people in any region that have had the virus — stood at 30 per cent in London and 26 per cent in the North East.

It’s thought that at least 60 per cent of a population need to have caught the virus for the group to reach herd immunity, which is when a disease runs out of room and can no longer spread because too many people are immune to it.     

The ONS estimates how many people have had coronavirus already by checking the blood samples of adults over the age of 16 for antibodies. It omits people living in care homes and prisons, or other communal settings.  

The data — which comes following the rapid spread of Covid over the past two months — may have been muddied by the fact millions of people have had a vaccine and will now show the same sign of immunity.

Outside of England, an estimated one in nine people in Wales had been infected by mid-January, up from one in 14 in December.

For Scotland, the estimate was one in 10, up from one in 13, and for Northern Ireland it was one in 11, up from one in 14.