Will city-wide testing halt spread of the coronavirus in Liverpool?

Liverpool street

Liverpool has been hit hard by the second wave of the coronavirus

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The UK government has announced plans to start regularly testing all 500,000 people in the city of Liverpool for the coronavirus. Here’s what you need to know.

Why test a whole city?

In theory, regular mass testing could help eradicate the coronavirus in just weeks. The UK government said in September that it wanted to try the approach nationwide – dubbed Operation Moonshot – and the Liverpool scheme is a pilot study. “I’m absolutely delighted,” says Julian Peto of the London School of Hygiene & Tropical Medicine, one of the signatories of an April letter calling for universal testing to be trialled in a city.

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Why might mass testing be better than just testing people with symptoms?

We know most cases of the coronavirus go undetected, often because people don’t even realise that they are infected. They might have no, mild or unusual symptoms, for instance, but can still infect others. If a bigger proportion of the people carrying the virus can be identified and isolated, there will be a bigger reduction in the spread of the virus.

Has this kind of thing been done before?

Yes. In May, China tested all 11 million people in the city of Wuhan, where the outbreak began, to prevent a resurgence of the virus. Chinese authorities clearly think mass testing works, because it has since been done in cities such as Qingdao and Kashgar, which have populations of 9 million and 5 million respectively. Slovakia is also experimenting with the concept – in the past week it tested two-thirds of its 5 million residents. “China and others have shown its feasibility,” says Keith Godfrey at the University of Southampton, UK.

Will it work in Liverpool?

It should help reduce the spread of the coronavirus. How big an effect it has will depend on three main factors. Will enough people come forward for testing? Can authorities set up the infrastructure needed to regularly test everyone and return their results quickly? And will people who test positive actually self-isolate? It will also be hard to tell if it is working because mass testing will start at the same time as a new lockdown in England.

So people need to be tested more than once?

Yes – unlike in China, the UK government isn’t committing to testing the entire population of Liverpool at once, meaning regular testing will be needed because only a small proportion of the city will be tested at any one time. The government press release doesn’t specify how often people will be tested in Liverpool, but this could be an issue because many people hate being swabbed for the coronavirus. There have been big drop-offs in participation in other schemes requiring regular testing. Godfrey says there has been a “fantastic” uptake rate in an ongoing pilot study of weekly mass testing in four schools and the university in Southampton, but this involves saliva testing rather than swabs of the nose and throat.

What happens if many people don’t volunteer for testing?

Peto thinks there needs to be a city-wide registry of everyone in Liverpool – where they live and with whom. That way authorities could get an idea of who is spreading the coronavirus even if they aren’t being tested. No plans for such a registry have been mentioned.

Are there enough tests available?

Not of the conventional tests that detect the genetic material of the virus. Instead, the government will also use what it calls “lateral flow” tests, which are similar to pregnancy tests. Such tests detect viral proteins, providing faster but less accurate results.

Will people who test positive self-isolate as required?

That remains to be seen. A study earlier this year found that only 1 in 5 people in the UK were self-isolating after developing symptoms. The government has since made it a legal duty to self-isolate after testing positive, with up to £500 in support for people on low incomes and fines of up £10,000, but it isn’t clear if this has made a difference. It will also be necessary to trace the contacts of those who test positive, but England’s existing test and trace scheme has been beset with problems.

Can the scheme be rolled out across the whole of England if it is successful?

Not in the same form, says Peto. The government is relying on commercial companies to provide tests in kit form, rather than doing testing in government labs with existing equipment, and he thinks companies cannot provide enough of these tests for the whole country. Around 2000 military personnel will also help out with testing in Liverpool but the army isn’t big enough to do this nationwide. “To roll it out at the national level will require a different system,” says Peto.

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source: newscientist.com