On a small industrial park in Belfast, a biomedical test manufacturer is pulling out all the stops. Biopanda Reagents is one of several firms across the UK that can make tests to detect the coronavirus, Covid-19. “There’s huge demand,” says sales manager Philip McKee. “We’re supplying to clinics, doctors surgeries, anywhere that would have a healthcare professional that can perform such tests.”
The company is taking on extra staff to help with packing and dispatch for orders “throughout Europe and across the world”. On March 12, speaking via phone, McKee says no fewer than 20,000 tests were due be shipped out the following day. However, he confirms that the NHS has not yet placed any orders with the company.
On March 11, NHS England said it intended to greatly expand testing capacity for Covid-19 – up to 10,000 tests per day. But the following day, the chief medical officer for England Chris Witty said at a Number 10 press conference: “We will pivot all of the testing capacity to identifying people in hospitals who have symptoms.”
Some healthcare experts take this to mean that the 10,000-tests-per-day target is now irrelevant and that only a subset of cases, the most severe, will be identified. That could be a big problem. “We're never going to know how really widespread the infection is,” says Neil Bhatia, a GP based in London. Martin Hibberd from the London School of Hygiene and Tropical Medicine agrees. “I think this is not sufficient. I would like to see more testing.”
Based on figures available on March 13, the UK has carried out around 30,000 Covid-19 tests, at a median of 1,600 tests per day so far in March. How and to what extent those numbers will increase is unclear. We contacted NHS England to ask about the details of scaled up testing within the NHS. The health body declined to comment. However, a spokeswoman for Public Health England (PHE) said: “There are 12 PHE labs engaged in Covid-19 testing in addition to a number of NHS labs which has increased the capacity to undertake these tests.”
Private firms that produce test kits are eager to respond to the need for wider diagnosis. One German company scaled up production so much that it produced four million individual Covid-19 tests in just a few days. And a British firm, Mologic, is working with partners in Africa to develop tests that will be manufactured in Senegal. As for who is providing testing resources within the UK, however, few details have been published.
Publicly listed company Novacyt, which has an office in Surrey, says it has enough raw materials to manufacture 3.5 million PCR tests that can provide results in a couple of hours. On March 16 the firm announced that PHE had bought £1 million worth of the tests – enough for four weeks of testing across hospitals.
There are, broadly, two types of test that can be used to detect Covid-19. PCR tests involve extracting RNA from nose or throat swab samples and converting it into DNA. This is then replicated many millions of times so that a significant quantity of DNA can be detected by a PCR machine. Detection indicates that the virus is present in the patient’s system. Generally, results take a few hours to more than a day to come through with this type of test.
Among the organisations that might get drafted into a wider testing effort are university biosecurity labs. Alan McNally from the University of Birmingham’s Institute of Microbiology and Infection says he and his colleagues are ready to assist testing efforts in the city, which are currently being carried out by PHE labs at Heartlands hospital.“At the moment we have not been mobilised as Heartlands is not stretched beyond capacity,” McNally says. “We have the ability to mobilise our entire research staff base to help if needed though that is unlikely.”
If called upon, McNally and his colleagues could process between one and two hundred samples per day, he adds. This would provide replicated DNA samples ready for PCR analysis to confirm the result elsewhere, for example at PHE labs.
The other sort of test relies on picking up evidence of antibodies. This is the type being manufactured by Biopanda in Belfast. McKee says the test itself looks a bit like a pregnancy test – it’s a plastic “cassette” type device into which a blood or plasma sample is inserted by a health professional. A strip inside the test causes a reaction when Covid-19 antibodies are present and a line mark appears on the cassette to indicate a positive result. It is ready within ten minutes.
Both PCR and antibody tests have advantages and disadvantages. The antibody detector outputs a result very quickly but it is less effective during the earlier stages of infection and may produce a false negative. The PCR test, on the other hand, is less effective towards the end of infection and also slower to output a result. It is generally very accurate, however, so long as the sample has been taken correctly – and that is the tricky part.
“The nasal swab is not always the easiest sample to get,” Hibberd says. He explains that, ideally, the swab is inserted right into the pharyngeal space – at the very back and sides of the nasal passage. He adds that he thinks both PCR and antibody tests should be done in tandem to give a clearer picture of how Covid-19 is spreading in the UK. And there is another benefit of the antibody tests, he says: “You can do that in healthy people and see whether two weeks ago, three weeks ago, months ago, they actually had the infection.”
Hibberd says that a national testing effort could make the extent of Covid-19 in the UK much clearer. However, he expresses concern at the government’s now openly stated position: that coronavirus should be allowed to infect a majority of the British population so that a sizeable number of people develop a herd immunity. “That doesn’t sound very good to my mind,” Hibberd says. “Maybe that’s the reality and we just have to face up to that but it’s quite a marked change.”
Updated 16.03.20 15:00 BST: The headline on this article has been updated and to add details of Novacyt's order from PHE
This article was originally published by WIRED UK
