Travellers to Britain from high-risk countries could safely stop quarantining if they test negative after seven days, scientists have suggested.
Fresh modelling has found that testing arrivals a week after entering the UK would identify 94 per cent of coronavirus cases.
It means that those who test negative would be almost certain they were not infected and could cut short their 14-day isolation at the midway point.
Ministers are still grappling with whether to reduce the two-week isolation period for arrivals from non-exempt countries, such as Spain which had its air corridor revoked suddenly last week.
Sources yesterday suggested the government was mulling reducing it from a fortnight to 10 days to persuade more holidaymakers to make trips abroad.
But a whole seven days could now be shaved off the isolation period in light of the findings which offer a much-needed boost to the hard-hit travel industry.
An intervention from the boss of Heathrow, who called for the shortening of quarantine for arrivals who test negative, could also sway ministers to review the two-week period which has left many reluctant to go on holiday.
Outbreak modelling conducted by the London School of Hygiene and Tropical Medicine (LSHTM) found that testing seven days after arrival will detect 94 per cent of cases.
Dr Sam Clifford, the paper’s author, conceded that testing after two weeks catches 99 per cent of cases, but pointed out that this costs people in quarantine an entire working week for a mere five per cent increase in certainty.
He said: ‘By seven days, a majority of people who will ever show symptoms will have noticed their symptoms and will self-isolate or seek medical attention.
‘Also by that time, PCR testing should detect most of those infections with a long incubation period or that will never result in symptoms, so-called asymptomatic infections.
‘We understand the need for people returning to be able to get back to their families and jobs.
‘Combining PCR (testing) with a week of quarantine could prevent up to 94 per cent of infectious persons entering, and could help people get back a week earlier than under the current two week quarantine policy – which we estimate catches up to 99 per cent.’
Heathrow’s chief executive has also weighed in on the government’s 14-day quarantine rules, which have been under the spotlight since its sudden decision to revoke the air corridor with Spain, which has seen a steady rise in cases.
John Holland-Kaye has called on the Government to help ease quarantine restrictions on passengers arriving from higher-risk countries with a scheme for coronavirus tests on landing.
He said the testing could be ‘up and running’ in a fortnight after Boris Johnson warned further European nations could lose their exempted status amid signs of a ‘second wave’ of Covid-19.
The Prime Minister triggered a diplomatic row with Spain by reimposing a warning against all but essential travel to the country and insisting travellers arriving in the UK from there spend 14 days in quarantine.
But he said ministers were looking at ways to mitigate the impact amid suggestions testing could be used to cut the time spent in isolation for those arriving from nations not exempted from the quarantine.
One idea floated is for passengers to be tested on arrival before being tested again a number of days later to confirm they are not infected with the virus. A second test could allow their quarantine to be shortened under the proposal.
Mr Holland-Kaye told the Telegraph he believed ministers are ‘very keen’ on a trial at airports.
‘We need to find a way of getting ‘red countries’ opened up again. Testing is the only viable way of doing that in the absence of a vaccine,’ he said.
‘A lot of countries which are ‘red-listed’ have millions of people who don’t have the disease and can’t travel. That’s holding back economic recovery.’
Government advisers have warned it can take a number of days from infection before tests return a positive result, meaning testing negative on arrival does not mean the passenger will not develop symptoms later on.
This is echoed by the scientists from LSHTM, who said testing on arrival would only identify around 50 per cent of cases, compared with 94 per cent after seven days.
Public Health England and the Department of Health and Social Care are understood to have spoken with travel assistance company Collinson to understand the proposed testing pilot it is developing with Heathrow.
Amid criticism from Spain for including lower risk regions in the quarantine restrictions, transport minister Baroness Vere of Norbiton said ways to impose more targeted restrictions were being examined.
‘For the time being, we are taking the approach by country for border measures, but it is the case that it could be that we put them in place for regions in the future,’ she told the House of Lords.
Earlier on Tuesday, Mr Johnson insisted the Government would not hesitate to act if flare-ups of coronavirus occurred in other destinations.
‘I’m afraid you are starting to see in some places the signs of a second wave of the pandemic,’ he warned.
Spain’s Prime Minister Pedro Sanchez has described the restrictions on travel to the country as an ‘error’.
He pointed out that the upsurge in coronavirus cases is focused in two regions, Catalonia and Aragon, adding: ‘In most of Spain, the incidence is very much inferior to even the numbers registered in the United Kingdom.’
Madrid had been urging the UK to exclude the Canaries and Balearics – which include popular tourist resorts on Ibiza, Majorca and Menorca – from its quarantine requirements.
But instead, official travel advice was tightened to bring the islands in line with the Spanish mainland.
Britons make up over a fifth of foreign visitors to Spain, which relies heavily on tourism, and Madrid has said the UK Government gave it no warning that the quarantine move was coming over the weekend.
Labour accused ministers of a ‘chaotic’ response and called for a flexible approach for struggling businesses to ensure that public health measures such as the change in quarantine rules for people returning from Spain do not lead to mass job losses.