Coronavirus testing: why there is a shortage of reagents

There is growing confusion about the government’s testing strategy. Cabinet Secretary Michael Gove, speaking at the Downing Street Press Conference yesterday, exacerbated the situation when he tried to explain why the UK had not managed to significantly scale up testing in recent weeks. Gove said:

“A critical constraint on the ability to rapidly increase testing is the availability of the chemical reagents which are necessary in the testing.”

This remark was quickly scrutinised by ITV’s Robert Peston, who claimed on social media:

“@michaelgove said just now that the difficulty in increasing the number of #COVID19 tests was due to a shortage of the relevant “chemical reagents”. Well I’ve just talked to the Chemical Industries Association, which represents the UK’s very substantial chemicals industry. It…has contacted its members and they’ve said there is no shortage of the relevant reagents.”

This is not entirely incorrect – the UK’s chemical industry is large, and the government perhaps should have done more to mobilise it earlier. But this tweet is confusing when it suggests that the chemical industry is the key to providing reagents for the UK’s coronavirus tests.

Reagents cause and facilitate chemical and biochemical reactions. At the moment, the most widely available method of testing for the virus responsible for the COVID-19 pandemic, SARS-CoV-2, is called PCR testing, or polymerase chain reaction.

The reaction which provides a result in the test relies upon a number of reagents to work. But talking to the chemical industry – and its public relations people or industry bodies – seems unlikely to be the chief remedy here because the most important reagents used in this method are not usually produced by this industry.

The chemical industry in the UK normally makes a range of products, including plastics, agrochemicals, and pharmaceuticals – but not those which are in most demand right now for PCR tests.

The important reagents required for these tests are specifically biotechnological. They are enzymes, such as reverse transcriptase and DNA polymerase, as well as primers and probes, such as synthetic oligonucleotides. These are produced in the life sciences industry and by biotech companies.

These reagents are put together by specialist diagnostics companies, such as Thermo Fisher, in an RT-qPCR “master mix”, which is then used to carry out the PCR tests in laboratories.

And according to the information we have so far – it seems that it is specifically this master mix and the primers needed to make it which are in short supply.

Dr Andrew Beggs said on Monday that the coronavirus testing lab being set up at the University of Birmingham is having trouble because “primer supply is slow: all suppliers are inundated at the moment” and “reagents are slow: RTQPCR master mix is difficult to get hold of”.

Professor Alex Blakemore, Head of Life Sciences at Brunel University, told The Times that: “Everyone in the world wants those same reagents, and the suppliers can only supply a certain amount”. “We are now in competition with the rest of the world…and other people have already bought up a lot of stock”, Blakemore said.

“If we were better prepared”, she added, “we might have made our own.”

Robert Colvile, Director of the Centre for Policy Studies, believes that there may be only a few very specialised life sciences firms globally who produce the appropriate reagents.

The UK does have an impressive biotech sector with a significant annual turnover. But this is a broad industry made up of many diverse companies, and, from a cursory examination, only one of them – Biofortuna – normally specialises in producing PCR reagents. Although, there are many others which are used to working with enzymes, DNA, and RNA.

At the moment it’s not clear how much of the supply shortage these companies could remedy.

And while UK’s chemical companies could presumably play a role in providing parts of the PCR testing master mix – such as Magnesium ions – it is not clear whether they are equipped to produce the mix itself. If they were able to convert their infrastructure in order to produce the mix of reagents, then this could indeed be crucial.

One thing is certain – none of this happens at the snap of a journalist’s fingers. There are several supply-side and institutional reasons why Germany has been so successful in mobilising their testing capacity.

One consultant chemical engineer at a big UK firm, now being asked to help the government secure more supplies, perhaps put it best. He told me: “I think people often use ‘chemical’ as a catch all term for small complicated things we can’t see.”

The demands of communicating quickly seem to have caused confusion about many complicated aspects of a crisis that the government now needs to make more transparent. But this confusion has been made worse by a media culture in which some seem eager to get the quick viral hit rather than carefully examining the detail.