UK Biobank today published the first results from a major government-backed study of the extent of previous infection with SARS-CoV-2 in different populations across the UK. It found evidence of previous infection in 7.1% of the study population, but with large variation in the rates between different parts of the UK and between different demographic groups.
This important study is determining the rates of previous infection in different parts of the country according to age, sex, ethnicity and socio-economic status, and monitoring how these rates change over time. Among people found to have been infected, it will also assess how long antibodies remain in the body, to help understand the potential for immunity.
UK Biobank has recruited 20,000 volunteers, a combination of existing UK Biobank participants and their children and grandchildren aged over 18, in order to produce results that are representative of the UK population. They have agreed to provide a finger-prick sample of blood using a kit sent to their homes, and filling out a survey about any symptoms they have had, every month for at least 6 months. Antibodies to SARS-CoV-2 in these samples, which provide evidence of previous infection with the virus, are being measured in a central laboratory at Oxford University.
These first results provide a snapshot for May and June of past SARS-CoV-2 infection, revealing that:
- Overall in the study, 7.1% of the participants had been infected previously
- There was no difference in the rates of previous infection between men and women, but the rates were higher in younger people (ranging from 10.8% in those under 30 to 5.4% in those over 70)
- Previous infection was most common among participants who live in London (10.4%), and least common among those who live in the South-West of England and Scotland (4.4% in both)
- Participants living in areas with higher levels of socio-economic deprivation had a higher rate (8.9%) of previous infection than those who live in more affluent areas of the country (6.1%)
- The rate of previous infection was higher among participants of Black (11.3%) and South Asian (9.0%) ethnicity than among those of White ethnicity (6.9%)
As a result of these independent trends, rates of previous infection were particularly high in certain sub-groups. For example, the rate was 18.4% in participants from ethnic minority groups who are aged under 30 and living in London. However, the differences between ethnic groups were not explained fully by where people lived or by their age.
Professor Naomi Allen, UK Biobank Chief Scientist, said: 'These initial results show that the rates of past infection with the coronavirus vary substantially within the UK population. It is not yet possible to explain why these differences exist and how they are interrelated. More detailed analyses of the characteristics of different individuals are ongoing to help understand the causes of the varying rates of infection.'
Results from blood samples taken each month will provide vital information about changes in the rates of previous infection in different groups of individuals across the UK throughout the remainder of 2020. Among people who have been infected, analyses of changes in the levels of antibody during subsequent months will help our understanding of the body’s response to infection.
Detailed information available to UK Biobank on the participants will be used to assess the impact of age and other characteristics (including genetic variation) on the persistence of antibody levels. And, since all the participants have given permission for access to their medical records, it will be possible to determine the rate of recurrence of SARS-CoV-2 in those who have previously been infected.
UK Biobank Principal Investigator, Sir Rory Collins, BHF Professor of Medicine and Epidemiology at The Nuffield Department of Population Health said: 'The extraordinary response to our request for volunteers allowed us to set up a large prospective study of SARS-CoV-2 antibody levels that is representative of the UK population. It is crucial that the participants continue to send blood samples every month, to enable us to monitor changes in the rates of infection as the UK comes out of lockdown and to understand the persistence of antibodies to the coronavirus as a measure of natural immunity.'
Sir Patrick Vallance, Government Chief Scientific Adviser, said: 'UK Biobank participants have already created a unique resource for health research and I am very grateful to them. Understanding the rates of infection and the persistence of antibody levels will be helpful for managing the ongoing process of coming out of lockdown safely, as well as supporting the development of vaccines against SARS-CoV-2.'