Health

Testing ALL of Britain for coronavirus every week 'could prevent second lockdown'

Testing everyone for coronavirus every week could drive out the coronavirus without a second wave or another lockdown, according to scientists.

Researchers led by the London School of Hygiene & Tropical Medicine said routine testing, contact tracing and household isolation could stop Covid-19 ‘quite quickly’.

They said Britain should do a single-city trial of the system to see whether it could bring down new infections and deaths faster than the current situation.

Applied nationwide, the policy would require 10million tests to be done every day – there are currently an average of 166,000 – and it could cost £1billion per month.

The idea has been dismissed in the past because people didn’t think that level of testing was feasible, the scientists said, but they argue there are ways to do it with basic saliva testing that can be carried out without expert lab staff.

It may be difficult to convince everyone in the UK to sign up to the invasive nasal swab testing, which people say makes them gag or suffer nosebleeds, but saliva testing is being trialled by the Government and could even be more accurate, the scientists said.

Researchers led by the London School of Hygiene & Tropical Medicine said 10million tests per day would need to be done to test everyone in the UK each week. The Department of Health is currently testing an average of 166,000 (two-week average)

Researchers led by the London School of Hygiene & Tropical Medicine said 10million tests per day would need to be done to test everyone in the UK each week. The Department of Health is currently testing an average of 166,000 (two-week average)

Researchers from the LSHTM worked with others from the universities of Bristol, Queen Mary and King’s College in London, Oxford, New York City, and the Institute of Cancer Research in London.

In their paper they said: ‘The Covid-19 epidemic can probably be ended and normal life restored, perhaps quite quickly, by weekly SARS-CoV-2 RNA testing together with household quarantine and systematic contact tracing. 

‘Isolated outbreaks could then be contained by contact tracing, supplemented if necessary by temporary local reintroduction of population testing or lockdown.’

They suggested that doing this repeated testing could cut the reproduction rate of the virus could cut out a third of transmission of the virus.

One in three cases are transmitted inside the home, the study said, and it takes an average of 6.5 days for people from one household to infect those from another.

Isolating the entire household when the first member tests positive, therefore, would prevent most of those transmissions because of the time it takes for the virus to move into the second person and then to the third.

It would ‘prevent the great majority of transmissions to the community from other household members infected by the case because they will not have been infectious for long, if at all,’ the researchers, led by LSHTM’s Professor Julian Peto, said.  

This could be more effective than the current system – in which only people with symptoms get tested, and they have to volunteer for a test – because it would catch people who didn’t know they were ill.

This is currently thought to account for around two thirds of all people with the virus in England.

The Office for National Statistics and scientists working on the COVID Symptom Tracker app have calculated that between 3,400 and 3,800 people catch the coronavirus each day in England.

But Department of Health testing has diagnosed an average of just 1,233 people per day over the past fortnight, meaning more than 2,000 daily are not getting tested. 

Professor Peto and his colleagues said the mass testing approach had been dismissed in the past because it would be too difficult to get so many done.

But they suggest a type of testing called RT-LAMP tests, which involves mixing samples of saliva with a chemical that would react to the presence of coronavirus and change the colour of the sample.

They said a lab with 100 staff could do 50,000 of these tests per day – enough to provide for a city of 350,000 people, about the size of Leicester.

The researchers called for a trial this size to be started and added: ‘The idea was not considered by the groups whose predictions have guided UK policy so we have examined the statistical case for such a study. 

‘The combination of regular testing with strict household quarantine… has remarkable power to reduce transmission to the community from other household members as well as providing earlier diagnosis and facilitating rapid contact tracing.’

But the suggestion of the mass testing has been shot down when suggested in the past.

One critic was a colleague of Professor Peto’s at the LSHTM, Professor Liam Smeeth, an epidemiologist.

Professor Smeeth said in April: ‘No country has managed to achieve anything approaching the level of testing being proposed… Nothing on that scale has ever been attempted.

‘In addition to the practical barriers, there is no scientific evidence to support the assertion that such a strategy would control spread of coronavirus.’

He added: ‘Scientists have the right to raise legitimate debate, but what we need to control this epidemic are practical, scientifically-driven strategies that are based on the best available evidence.’ 

The study was published in the journal Royal Society Open Science. 

TEST AND TRACE’S DEFINITION OF ‘CLOSE CONTACT’ IS GOOD ENOUGH, STUDY SAYS

Scientists say the definition of a ‘close contact’ being used by the NHS test and trace system is good enough to reduce the spread of the disease.

Someone who has spent 15 minutes or more within 2metres (6’7″) of someone with coronavirus is an accurate, if over-cautious, definition of an at-risk contact, experts at the University of Warwick and Lancaster University said.

Isolating everyone in that category would result in a lot of non-infectious people having to go into lockdown unnecessarily, the scientists said, but should successfully reduce the spread of the virus.

In a study the scientists quizzed 5,802 people about their social contacts.

They found that, on average, people came near to 217 people over the course of a fortnight. And around a quarter of those people (59 people or 27 per cent) constituted a close contact who could be considered at risk of infection. 

Using the 2m definition of a contact, only one in six people would have been near someone who could have been infected but not listed as a contact. 

Some people would have had contacts who they didn’t know and couldn’t refer, it said, while others would not be able to work out where they got the virus from.

Using a stricter rule might reduce the number of people who needed to be contacted, helping the system work faster, but would raise the risk of contacts being missed.

The researchers Dr Matt Keeling and Dr Jonathan Read said: ‘The current tracing strategy within the UK is likely to identify a sufficient proportion of infected individuals, such that subsequent spread could be prevented, although the ultimate success will depend on rapid detection of cases and isolation of contacts.’

The research was published in the Journal of Epidemiology & Community Health.

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