Video report by ITV News Political Correspondent Daniel Hewitt
Some 20,000 households in England are being contacted to take part in a study to track coronavirus in the general population.
The study aims to improve understanding of infection levels and how many people may have immunity to the virus.
All participants will provide a nose and throat swab to test for whether or not they currently have the virus, while adults in some 1,000 of the households will provide a blood sample to find out what proportion of the population has developed antibodies to Covid-19.
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Initial findings are expected in early May.
In total, the government says some 25,000 people will take part in the pilot phase with plans to extend it to up to around 300,000 over the next 12 months.
The launch of the study comes on the same day that human trials for a potential coronavirus vaccine began.
The Department of Health and Social Care (DHSC), leading the study with the Office for National Statistics (ONS), said participants will form a representative sample of the UK population by age and geography.
Those selected will provide samples taken from self-administered nose and throat swabs and answer a few short questions during a home visit by a trained healthcare professional.
Swab tests will show whether or not participants currently have the virus.
They will be asked to take further tests every week for the first five weeks, then every month for a year.
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Scientists will also analyse blood samples from adults in around 1,000 households to determine how many people have developed antibodies to the virus.
Antibody testing is considered crucial in providing an exit pathway from the current lockdown, and also providing data to those developing a vaccine.
England’s chief medical officer Professor Chris Whitty said at Wednesday’s daily Downing Street briefing that there is currently not a test available that Public Health England (PHE) has enough confidence in.
Scientists at Oxford University are in the process of validating an antibody test, also known as an Elisa test, which will be used in this study.
They are on track to have a “fully validated and an accreditation compliant test” in place by May 4 according to Professor Derrick Crook, who is among those co-ordinating the programme of work at Oxford.
This laboratory test will be used in the study by DHSC and ONS, but Prof Crook said there is capacity to process well over 20,000 tests a day should there be such a demand for testing.
Participants in the antibody test will be asked to give further samples monthly for the next 12 months.
The Government says nose and throat swabs will be taken from all participating households, whether their members are reporting symptoms or not.
Blood for antibody tests will not be taken in any households where someone has symptoms of Covid-19 or is currently self-isolating or shielding.
The study will involve the University of Oxford, data science company IQVIA UK and the National Biosample Centre in Milton Keynes.
DHSC said healthcare workers will use recommended precautions to protect themselves and everyone in the household from getting the virus, and tests will be undertaken by the IQVIA nurse in the participant’s own home.
Although swab test results will be given to participants via their GP, it is not thought participants will a receive their results.
The de-identified blood samples will be sent to Oxford University to be tested for antibodies, while infection testing swabs are to be sent to UK Biocentre.
Health Secretary Matt Hancock said: “This survey will help to track the current extent of transmission and infection in the UK, while also answering crucial questions about immunity as we continue to build up our understanding of this new virus.
“Together, these results will help us better understand the spread of the virus to date, predict the future trajectory and inform future action we take, including crucially the development of ground-breaking new tests and treatments.”
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