Tests used by NHS... but not trusted by ministers

WHY is the Government so reluctant to introduce Covid testing at our borders?

More than 30 other countries are already trialling airport testing schemes. MPs and scientists are behind the idea – and the travel industry is desperate for it.

Yet British ministers are hesitant. Why the trepidation?

The problem, they say, is that the PCR test – the very same swab test used in hospitals and by the NHS Test and Trace scheme to detect Covid-19 infections – is not very good at detecting the virus if someone does not have symptoms. This is true – up to a point. The PCR test relies on a swab of the throat and nose. If someone is not ill – if they don’t have a cough – the virus may still be

deep in the lungs, where a swab cannot get to it. This is the reason that up to a third of Covid tests are ‘false negatives’, giving someone the all-clear when in fact they are carrying the virus.

Testing is not perfect, but it is the best tool we currently have.

After all, it is deemed good enough to be used each day on thousands who do not have symptoms.

Testing of asymptomatic people, for example, is judged accurate enough for care home staff and residents, a core part of the Government’s strategy to protect the social care sector.

Many hospitals are now regularly testing NHS staff, whether or not they have symptoms, using the same tests.

And the Office for National Statistics’ weekly population testing survey, which is key to informing the speed at which the Prime Minister eases or tightens lockdown restrictions, is based on randomly testing 28,000 people without symptoms every fortnight.

Eventually Health Secretary Matt Hancock wants to test every person in the country each week, a ‘moonshot’ he hopes will end the need for social distancing.

So if asymptomatic testing is accurate enough for all of that, why is it not good enough for airport screening?

The answer is that ministers are terrified

of infections being imported from abroad. In February and March, when they resisted pressure to impose border restrictions, countless Covid cases were seeded into Britain from China, Italy, Spain and Austria.

After getting it wrong in the spring, politicians do not want to be accused of allowing a repeat. But they are ignoring the safety net at their disposal.

Put aside the fact that asymptomatic PCR testing is considered to be accurate enough for care homes, for the NHS, for Test and Trace, for generating data crucial to Government policy.

Even if we ignore this, there is an answer – double testing.

If air passengers are tested once on arrival, only per cent of cases would be picked up, Transport Secretary Grant Shapps claims.

That is almost certainly an underestimate. But even if we accept his figures, repeat testing would see detection soar. If passengers are tested for a second time five days after arrival, pick-up rises to 85 per cent of cases. And if the second test is carried out after eight days, 96 per cent are detected.

Double testing picks up missed cases because the vast majority of those who were asymptomatic early in their incubation period are symptomatic a few days later, meaning the PCR test is much more effective. That was the conclusion of a Public Health England analysis in June for Sage, the Government’s advisory panel. Yet it was rejected.

In the words of Professor Linda Bauld, of Edinburgh University, there should be a rethink. ‘It would almost certainly be a better option than the current quarantine regime,’ she says.

‘People with negative tests would be able to get back to work and education more quickly and, if implemented properly, it would reduce the risk of community transmission of the virus from those currently asked to quarantine for two weeks who simply can’t – or won’t – comply.’