Coronavirus: How does Covid-19 test-and-trace work? Published duration 12 hours ago Related Topics Coronavirus pandemic

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England and Wales are launching a contact tracing app on Thursday 24 September.

The app - which can be downloaded on a smartphone - will tell people to self-isolate if their phone detects they were near someone later found to have Covid-19.

How does the contact tracing app work?

People with Apple and Google phones will be asked to download the app, which detects when a fellow user is nearby.

When two phones running the app are near each other, they will make make contact through Bluetooth.

If they are close for a long enough time, and one of the two owners later shares a positive coronavirus test via the app, then the other will receive an alert.

Hospitality venues such as pubs and restaurants will be asked to display posters with a QR code, which app users will scan to ''check in'' to their location.

The posters will also go up in communal areas of community buildings like universities, hospitals and libraries.

Used alongside manual contact tracing, the app will help identify close contacts of a user who tests positive, or visitors to a premises that has suffered an outbreak.

How has contact tracing been carried out until now?

People who display coronavirus symptoms and test positive have been contacted by text, email or phone. England's NHS Test and Trace service calls only from 0300 0135 000.

They are asked to log on to the NHS Test and Trace website and give personal information, including:

name, date of birth and postcode

who they live with

places they visited recently

names and contact details of people they have recently been in close contact with

Close contacts are:

people you've spent 15 minutes or more with - at a distance of less than 2m (6ft)

sexual partners, household members or people you have had face-to-face conversations with - at a distance of less than 1m

Contact must have taken place within a nine-day period, starting 48 hours before symptoms appeared.

No-one who is then contacted will be told your identity.

What happens to people who are then contacted?

If you are approached because one of your contacts has tested positive, you must stay at home for 14 days from your last point of contact with them.

Others in your household won't have to self-isolate unless they also develop symptoms, but must take extra care around you regarding social distancing and hand washing.

How is the tracing scheme going?

The prime minister claimed the UK's test and trace system would be "world-beating". But it has encountered several problems since its launch in May.

Of the people referred to the contact tracing system between 27 August and 2 September, 83% were reached and asked for a list of their contacts, and 69.2% of those contacts were reached and asked to self-isolate.

Sage, which advises the government, has said that at least 80% of contacts would need to isolate for it to work properly.

The mobile app was meant to launch in mid-May and form a key component of the UK's tracing strategy. But the original attempt, which used a ''centralised'' approach to storing data, had to be abandoned.

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An NHS Test and Trace call does not always mean a pub or restaurant must close. It depends on the circumstances and when the infected person visited.

What about sick pay?