The UK is embarking on a large-scale study of 300,000 people to find out what proportion of the population has already had the coronavirus and how many may have some immunity to it as a result.

Studies are being undertaken around the world to work out how widespread the infection is. So far, they have found the proportion of people with antibodies showing they have been infected is low. The World Health Organization said this week it appears that only around 2 to 3% of people in the general population have been infected – with or without symptoms.

The results of the new major British study will be crucial for planning a strategic endgame to the pandemic in the UK. Some 25,000 people will be invited to take part in the first wave of the study in England. It is expected it will be extended to 300,000 people over the next 12 months.

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All those who take part will provide samples from self-administered swabs of their own nose and mouth and answer questions from a visiting nurse, to determine whether they have the virus at the outset. Over the next year, they will be asked to take further tests every week for the first five weeks, then every month for 12 months.

Around 1,000 people will be invited to have a blood test every month to find out whether they have antibodies to the virus. The hope is that those with antibodies may have some immunity from Covid-19, which might allow them to resume more normal lives. Scientists have warned, however, that even if there is some protection, they do not know how long it will last.

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It is now widely accepted that the way out of lockdown will not be through herd immunity, as a result of a large proportion of the population experiencing infection. The risks to lives and to the NHS are too great. Once social distancing and the stay-at-home policy have brought the case numbers low, there will have to be rigorous testing of everyone who has symptoms and tracing of their contacts, who will be instructed to self-isolate.

The health secretary, Matt Hancock, told the House of Commons on Wednesday that the government was committed to “ramping up” testing and contact-tracing “in a matter of weeks” in order to allow social distancing to be relaxed. Effectively that will be a return to the policy Britain abandoned in early March when the numbers of those falling ill began to rise rapidly.

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Contact tracing will be assisted by the use of apps on mobile phones, which will alert people who may have been in contact with somebody who has tested positive. The foreign secretary, Dominic Raab, told the Commons he believed the British public would accept something they might otherwise consider an invasion of privacy. “I think people do understand that we’re in an exceptional crisis and we need to take measures which we probably wouldn’t think of doing if we weren’t in this crisis,” he said.

Over 600,000 volunteers have been approved to help those most at risk who are isolating at home from coronavirus, the NHS and Royal Voluntary Service has said. Healthcare practitioners, pharmacists, local authority and social care staff have been calling on volunteers to carry out around 35,000 tasks over the past two weeks, including delivering medicines, shopping and other supplies as well as making calls to check in on those isolating at home.

In some areas volunteers have been called upon to take blood pressure monitors or other equipment to patients’ homes to enable health professionals to remotely monitor their health.

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