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DnaNudge Deploys Direct-to-Consumer Service for PCR-Based Pool Testing of SARS-CoV-2

NEW YORK – UK startup DnaNudge has introduced a direct-to-consumer service for testing groups of people for SARS-CoV-2, the virus that causes COVID-19. Called the COVID Bubble Test, the service allows the testing of up to 10 people on a single cartridge for £100 ($133), or £10 per person.

DnaNudge's new service relies on the principle of pool testing, where sputum samples are collected from each person in a group, also called a pool or bubble. Sputum samples can be collected at home and then mailed to the London-based company for processing by real-time PCR. Turnaround time for the test, which is targeted to asymptomatic people who might still be carriers of the disease, is about 90 minutes.

The company initially offered the test via its store in Covent Garden in London and moved in recent weeks to a DTC model, allowing customers to order kits online and mail in their sputum for analysis, a business decision that happened to coincide with the latest lockdown in the UK.

"We have been inundated by requests for the test," said CEO Chris Toumazou. "People want to take the test because they want to see their loved ones at Christmas, or they have children returning from school," he said. "So families are interested in doing family bubbles, offices are interested in doing office bubbles."

One early user group was the London Symphony Orchestra, 40 members of which took the COVID Bubble Test so they could resume rehearsals. While it is technically feasible to test as many as 40 people on each cartridge, Toumazou said the number of individuals that can be tested per bubble largely depends on the prevalence in the area where the testing is taking place.

Hospital workers, for instance, might prefer to undergo COVID-19 testing in smaller bubbles of two or three people because if the sample is found to be positive, the entire bubble would need to self-isolate while each member of the pool is retested. Larger bubbles would make sense in the case of, say, an orchestra, where members have already been exposed a lot to each other.

'War zone learning curve'

A year ago, prior to the COVID-19 pandemic, DnaNudge was an up-and-coming, direct-to-consumer genetic testing firm offering clients information about their genetic risks for conditions like diabetes, obesity, and heart disease, as well as recommendations on changes to nutrition and behavior, based in part on data derived from a handheld real-time PCR platform called the NudgeBox. The company quickly refocused its energies toward the public health crisis, though, and developed a point-of-care assay for SARS-CoV-2, called CovidNudge, which received the CE-IVD mark this summer.

In August, the UK National Health Service ordered 5.8 million COVID-19 tests from DnaNudge, an order that has prompted it to scale dramatically. Between April and December, a period during which Toumazou said the firm was going through a "war zone learning curve," DnaNudge grew from 60 employees to 110. It also inked agreements with Jabil Healthcare to make its cartridges and Benchmark Electronics to fill the order for NudgeBoxes. 

"One of the biggest problems with an innovation like this is scaling something of medical-grade quality rapidly and making it manufacturable," said Toumazou. The firm is now putting the skills it gained along the way to use as it makes CovidNudge, as well as the new Bubble Test, widely available.

The CovidNudge tests are already available at more than 80 hospitals across England, Northern Ireland, Scotland, and Wales, a number the firm is hoping to double. "The deployment is happening," said Toumazou of the company's NHS order. In addition to being used in accident and emergency departments, he said it is also being rolled out in mental health and maternity wards, just as the UK has experienced a "significant rise" in cases.

According to the World Health Organization, there have been 1.6 million confirmed cases of COVID-19 in the UK since the pandemic began late last year, including nearly 60,000 deaths. There has been a recent spike in cases, too, with 100,000 new cases reported within the past week. Because of this second wave of the pandemic, the UK entered into a new lockdown on Nov. 5.

It was against this backdrop of rising cases that DnaNudge developed the COVID Bubble Test, an idea that Toumazou said the company began to explore in August. While the sample collection approach is different, the assay is the same real-time PCR test that the company uses on its point-of-care, CE-IVD-marked NudgeBox. Therefore, DnaNudge didn't need to seek a separate regulatory approval for its COVID Bubble Test, but rather updated its instructions for use (IFU).

"It's still the same primers, the same assay we've been using," noted Toumazou. The key difference is how the samples are collected. The company's SARS-CoV-2 point-of-care test is run using nasopharyngeal swabs, while the Bubble Test relies on sputum, or as Toumazou refers to it, gob. "We ran an internal validation comparing the gob samples to nasopharyngeal swab samples," he said. "So we were able to update the IFU with just a new sampling modality."

'Like a paintbrush'

Since the beginning of the COVID-19 pandemic, nasopharyngeal swabs analyzed by real-time PCR have been the go-to test for detecting SARS-CoV-2. Given the need to test large numbers of people to bring down turnaround times and costs, the idea of pool testing – combining or pooling samples, running an analysis, and then retesting individuals in the pool if the group test comes back positive – has been considered, though its adoption has been arguably slower.

In June, the US Food and Drug Administration issued its first guidance on pool testing of asymptomatic individuals for SARS-CoV-2. In recent months, a number of diagnostics players have received Emergency Use Authorizations for PCR-based pooled testing of samples for the virus, including Quest Diagnostics, Laboratory Corporation of America, and PerkinElmer.

Toumazou noted that these tests are still run in labs on samples diluted by viral transport media, differing from DnaNudge's direct-to-cartridge approach. He added that, in general, pooled testing has yet to gain widespread uptake because of concerns around sample dilution and turnaround time. As sputum samples are often transported via viral transport media, and then pipetted into cartridges for analysis, there is a chance of sample dilution, and thus, false negatives or positives. It also takes more time to retest each sample if a pooled sample is found to be positive. 

Toumazou said DnaNudge avoids dilution issues because the samples are run directly on the cartridges.

"It's like a paintbrush," said Toumazou of the company's technique. "We are dipping one swab in each of those pots and then that one swab goes into that cartridge, so there is no real dilution."

Should a sample come back as positive, the company also retains swabs from each individual to identify the positive case or cases in the bubble. Results are then delivered to customers via text message, along with recommendations on the appropriate steps to take in line with UK government guidelines.

Toumazou said the company is preparing a paper on its validation of the approach.

There are several other companies selling real-time PCR-based SARS-CoV-2 tests to UK customers directly, among them Concepta and LetsGetChecked. Both firms' tests rely on nasal swabs, though, and they do not offer group testing services. Concepta's MyHealthChecked test retails at £95 and LetsGetChecked's Coronavirus Test sells for £124 in the UK.

Currently, the UK is the main market for DnaNudge's tests, but it does have plans to launch the Bubble Test, along with its consumer service, outside of the country next year, said Toumazou.

Now nearly a year into the pandemic, Toumazou noted that he regards his firm as a battle-hardened medical diagnostics player that is offering innovative tests while retaining a vetted technology, PCR.

"There has been a new wave of technology coming through," Toumazou said of the diversity of tests that have been developed in response to the pandemic. "DnaNudge is a bit different in that we are trying to introduce gold standard PCR tests that can be used by the masses very quickly."