Hunt clash with Whitty puts testing regime into spotlight

Select committees can often be dry, technical affairs as MPs quiz experts and ministers on the rationale and consequences of specific policy decisions.

Not so at a bumper health committee this week, which saw sparks fly between Prof Chris Whitty, England’s chief medical officer, and Jeremy Hunt, the former health secretary.

In heated exchanges, the pair clashed over the decision to abandon mass testing on March 12 – a widely criticised move which has been identified as one of the key reasons for Britain’s high coronavirus death toll.

“We had no capacity to do [testing] on the scale that was needed,” Prof Whitty said. “The idea that you can suddenly switch this on, I’m afraid, is incorrect.”

Throughout March and April, as the Government worked to ramp up this diagnostic capacity and hit Matt Hancock’s 100,000-a-day testing target, two major explanations were given for delays.

First, the Government said it was incredibly difficult to set up testing infrastructure from scratch. There was also a global shortage of the chemical reagent needed to run the lab-based PCR molecular tests used to detect if someone is infected with the virus.

But months later, after predictions about the potential scale of a “second wave” come autumn, some experts are questioning whether these issues are fully resolved. Is the UK prepared, or has the third element of the “Holy Trinity” of vaccines, therapeutics and diagnostics been neglected? There is some good news. According to Will Irving, professor of virology at the University of Nottingham, “there is no doubt that we could do an awful lot more tomorrow, if we had to, compared to April 1”.

When the first wave hit in March, the UK had no diagnostics. Now there are not only tests, but also the experience and infrastructure required to use them. According to the Department of Health and Social Care, the UK has created the “largest diagnostic testing industry in British history” – including 73 drive-through sites, 236 mobile testing units and three mega “Lighthouse” laboratories.

But Prof Irving says there are still flaws in the overly centralised system.

“I don’t necessarily think the Lighthouse route was the right one. It’s inhibited labs that were perfectly capable of doing tests from the start and local data is slow to reach local public health providers, as we saw in Leicester,” he said.

Prof Peter Piot, director of the London School of Hygiene and Tropical Medicine, said: “There’s still a lot of unused testing capacity in universities and private labs.

“Academic centres are ready to contribute, but at the moment it’s been limited to the NHS and the public sector.” However, he adds that “the bigger problem at the moment is the turnaround time” – unless tests are returned within 24 hours “it’s useless from the perspective of controlling the spread”.

This is an area where the UK has improved. In early May, 16 per cent of tests were returned in under 24 hours, a figure the Government says is now 91 per cent. But Karol Sikora, chief medical officer of Rutherford Health and former director at the WHO, believes even a 24-hour wait could be too long to curb the spread.

“We need a one or two-hour test based on saliva or a low-nose swab, that is cheap and provides results at the point of testing,” he said, referring to antigen tests.

They are difficult to develop but could revolutionise testing, Prof Sikora said, by putting less pressure on laboratories and allowing frequent mass screening to pick up asymptomatic cases, a major source of Covid-19 transmission. Few have so far been approved by regulators – partly due to a lack of investment in this third strand of the Holy Trinity. “Despite a lot of potential to change the trajectory of the pandemic, diagnostic development is still cash-strapped,” said Dr Rangarajan Sampath, chief scientific officer at the Foundation for Innovative New Diagnostics (Find).

“Compared to vaccines and treatments it’s hard to generate the same kind of energy and excitement to attract funding – yet without diagnostics you’re taking a stab in the dark and can’t track an outbreak.”

In general, regulators ask for 80 per cent sensitivity (at most 20 per cent of tests return false positives) and 97 per cent specificity (fewer than three per cent give a false negative).

But Dr Joe Fitchett, medical director of the Mologic, a UK-based company developing an antigen test, says that PCR tests could miss as many as one in 10 cases because they tend to test symptomatic patients.

Patients appear to be most infectious within the first five days of contracting the disease, before many show any signs of illness, so identifying asymptomatic individuals is critical. If antigen tests miss three in 10 cases, but pick up seven other individuals, that’s a major win for public health.

“We do not need these [antigen tests] to be perfect,” said Dr Michael Mina, an immunologist at Harvard University who co-authored the report. “We just need them to reliably detect people on the days they are most likely to transmit virus.”

The Government says it is exploring the “potential of new technologies through robust trials”, including a saliva antigen test being developed by the University of Southampton.

But Dr Fitchett says that a pivot away from a focus on “gold standard” diagnostics will be one of the most critical determinants of whether the UK is prepared for a second wave.

While infrastructure for PCR tests is likely to meet a surge in demand, disease surveillance and our ability to track asymptomatic spread – whether in hospitals or the community – is currently lacking. “At the end of the day, the more important question for me is ‘how do we meaningfully and usefully deploy tests’ in light of their strengths and weaknesses,” Dr Fitchett said. “Expecting antigen tests to be as sensitive as PCR missed the point.

“We need antigen tests, PCR tests and a coherent diagnostic strategy to detect infectiousness and halt transmission. This is only going to become more important come winter.”