Covid: How does mass testing work?

The government hopes that mass testing will allow it to ease the current coronavirus restrictions.

How does mass testing work and what does it achieve?

Mass testing makes it easier to find people who may be unaware that they are infected.

They can then be told to isolate and be prevented from spreading the virus.

Mass testing can also be used in more targeted ways, including:

Several types of test have been developed but two have mainly been used - both involve swabbing the nose or throat.

If you have been tested at a hospital, a drive-in centre or used an NHS home-testing kit, this is the test you are likely to have taken.

The PCR test involves swabbing your nose or throat, dropping the swab in a vial of liquid and sending it off to a lab for analysis.

It is regarded as the most reliable test, but it normally takes a day or longer to get a result.

This is a rapid test involving a handheld kit, that gives a result in about 20 minutes.

Like the PCR test it involves a swab from the nose or throat, which is dropped into liquid. The solution is then added to a test strip, a bit like a pregnancy test, which shows up a result in 20-30 minutes.

There have been some concerns about the reliability of lateral flow tests following an evaluation of a pilot scheme in Liverpool.

The tests were not found to be good at picking up relatively small amounts of virus. On the other hand, they did identify the majority of the most infectious cases, and had the obvious advantage of being quick.

The government has paused plans to roll out rapid testing of close contacts in schools, except for a small number of secondary schools and colleges.

Health officials say the emergence of a new variant means the risk of missing infections has risen.

Regular testing of staff will meanwhile increase to twice a week.

It's not currently clear how testing of pupils will be organised once schools reopen.

Currently, most people can only have a test if they already have symptoms.

But the government would like to roll out mass testing in areas with high infection rates.

In the pilot scheme in Liverpool, everyone living or working in the city was offered a voluntary lateral flow test.

Cases there fell from 635 per 100,000 people in mid-October to 99 by mid-December. Mass testing began on 6 November.

In addition to testing the general population, local authorities could also target high-risk workplaces and hard-to-reach communities.

Anyone who gets a positive result to either test must immediately self-isolate for at least 10 days. Their contacts will be traced by NHS Test and Trace, and must also isolate if told to do so.

Self-isolating means staying at home and not leaving even to buy food, medicines or other essentials, or for exercise.

People should order online groceries, or ask friends and family to get supplies and leave them outside the front door.

People in England who fail to self-isolate after a positive test can be fined up to £10,000.

Anyone on a low income who has been told to self-isolate in a phone call from NHS Test and Trace can claim a £500 payment from their local authority.