Heathrow wants to test passengers who arrive in the UK for coronavirus.
The airport proposes to trial a polymerase chain reaction (PCR) test, similar to that in the NHS.
It would take a nose and throat or saliva swab and produce a result in between five and 24 hours. Because of the risk that it may not detect Covid-19 in pre-symptomatic or asymptomatic passengers on arrival, it would be repeated in either five or eight days after the first test.
This covers the time that scientists estimate it takes the virus to incubate during which time those infected may not display symptoms but could still spread it in the community.
Passengers would be expected to quarantine as normal until they received a double negative result, at which point they could be freed early from the normal self-isolation of 14 days.
Heathrow is proposing the test for people coming from current “red list” countries like Spain but wants to partner with Canada and Singapore which have sophisticated testing systems that could allow passengers to be tested 72 hours before they flew.
This could reduce the time in quarantine in the UK to as little as two days. In the longer term, it argues it is critical to opening up trade with partners like the US.
Who would pay for it?
The test would cost £150 but the airport and its developers Collinson Group, medical specialists, believe the increasing volumes of tests would cut the costs. They say they need an amendment to the quarantine regulations exempting people from continuing to self-isolate if they test negative, otherwise there is no incentive for people to undergo the test.
How accurate are the tests?
The five-day-spaced test reportedly has an 85 per cent accuracy rate, rising to 95 per cent for the eight-day test. The PCR test has been used in the NHS on patients reporting symptoms, which dramatically improves accuracy. The problem with asymptomatic patients is that the swab may not have been deep enough to capture traces of the virus or because the viral load is in the lungs and not detectable by swabs.
Public Health England (PHE,) which has been in talks with Collinson Group, is understood to have insisted on two tests because of concerns that it may not identify asymptomatic passengers.
The Department of Health is also concerned that people may be less incentivised to abide by quarantine if they are negative after their first test.
What are other countries doing?
People travelling to France from 16 countries deemed “high-risk” will have compulsory PCR tests on arrival from August 1 with negative results exempting them from quarantine. Countries include the US, Brazil, India, Israel and Algeria. France claims its free one-stop test paid for by the Government is 80-per-cent reliable.
From next week, Germany will introduce compulsory PCR tests for all those arriving from “risk areas”. Those arriving from anywhere else can take a test should they want. Costs vary as they are set by federal states.