Whose contacts will be traced? England’s new “NHS test-and-trace” system kicks in when a patient receives a positive test result for coronavirus. Unlike in the early days of the outbreak, everyone experiencing symptoms will be expected to take a test. At the same time as ordering the test, by calling 119, or going to the NHS website, patients will be asked to take part in the tracking programme. If the result of their test is positive, anyone they have been in close contact with will then be contacted, and asked to self-isolate for 14 days, even if they have no symptoms. What counts as ‘close contact’? It means anyone who has been within 2 metres of the infected person for more than 15 minutes without protective equipment – something test-and-trace chief Dido Harding says should be rare if workplaces are operating in accordance with “Covid-secure” guidelines. The government also hopes the requirements of the new system in England will focus the public’s minds on the importance of continuing to stay 2 metres apart from others, as much as possible. Once the app is up and running, the patient’s mobile phone should automatically identify anyone they have come close to. But until that happens, patients will be asked to identify likely contacts themselves, via an online process. What happened to the app? Matt Hancock, the health secretary, announced the pilot of a new NHS tracing app on the Isle of Wight earlier this month, and had hoped it would form an integral part of the contact-tracing system, saying: “Where the Isle of Wight leads, Britain follows.” But it is yet to be cleared for launch, as developers tackle glitches. Ministers have been stressing more recently that on-the-ground tracing, involving local public health teams as well as call-centre staff, is more important. Will there be fines to enforce the new requirements? Not to begin with. Harding stressed that, for the time being, the new system will rely on the voluntary compliance of the public. But ministers do have the legal power to enforce self-isolation requirements with fines, if it is deemed necessary at a later stage. Travellers who break the new quarantine regime for arrivals at airports and ports will already be charged up to £1,000 if they breach the restrictions. Does the NHS have the testing capacity to back up the new system? The latest official daily testing capacity figure was a record 154,120, and the Department of Health insists it will achieve the 200,000-a-day target set by the prime minister by the end of May – later this week. The former health secretary Jeremy Hunt has warned that long waits for some test results could hamper the effectiveness of the new system. Harding has acknowledged she is keen to increase the speed of the entire system, including the turnaround times for results, some of which are still taking more than 24 hours to return. Could people end up having to self-isolate repeatedly? They shouldn’t: Harding suggested if people in a particular workplace or local area appear are repeatedly showing up as in close contact with sufferers, local public health authorities could intervene to investigate. Part of the rationale for the new system is meant to be to allow local, small-scale action to be taken, such as shutting down particular services or businesses, where there appears to be an outbreak. Will people who have already had Covid-19 be exempted from the requirements to self-isolate? No. Scientific advice remains that we cannot be certain whether having had the virus means a patient has immunity. So even someone who has had a positive test for Covid-19 in the past, will have to stay at home for 14 days if they have come into contact with a new sufferer.