Modernizing POC Diagnostics

Pandemic containment in the United States has proved ineffective due to a lack of preparation and deployment of modern pathogen-detection technologies. Improved point-of-care molecular diagnostics will save lives when the next pandemic emerges.

 

SARS-CoV-2
Author: Dr. Jack Regan, CEO and Founder of LexaGene

The response of the United States to this pandemic was and continues to be ineffective in the area of containment due to lack of preparation, planning, education, and the absence of pandemic-fighting technologies. As of this writing, the United States has lost >527K citizensand sustained significant economic losses in a little over one year. The responsibility falls on current and past leaderships who have not adequately addressed the weaknesses in our defenses, despite arguably decades of warnings from virologists, microbiologists, epidemiologists, and members of our public health community. The intent of this article is not to cast stones, but to offer a strategy on how diagnostics can be revamped to better meet the unpredictability of the microbial world.

We need to modernize our defenses against sudden and unexpected microbial attacks, which could come from the next novel pathogen, referred to in pandemic prevention planning as Disease X. If investments are made now in the right type of diagnostics and surveillance infrastructure, as described below, I believe the future world will be better prepared to prevent the loss of many lives caused by the next inevitable threat.

 

Three Ways to Modernize Diagnostics to Curb Infectious Disease

 

Promote Molecular Point-of-Care Testing

Shortening time-to-result can have a significant impact on preventing additional infections. Meaningful time-to-result improvements can only be achieved by supporting technologies that are operated at the point-of-care (POC) so that shipping samples to distant reference laboratories can be avoided. There is a wide range of technologies for point-of-care testing, however, the vast majority used today are antigen-based, and these have poor sensitivity.

Instead, we need to focus our efforts on molecular testing, which has superior sensitivity. Unfortunately, due to the complexity of molecular testing, the vast majority of molecular tests are performed in reference laboratories. Fortunately, advancements in microfluidics have resulted in the development of PCR-based technologies that can process samples at the POC. These technologies can return results in 45 min to 3 hours, which is a stark improvement over tests sent to a distant reference laboratory. To make a significant impact, these systems need to be omnipresent, so that they are in use on every floor of every hospital and inside all urgent care clinics, pharmacies, large places of employment, doctors’ offices, and even schools.

 

Promote Multiplex POC Testing

Speed (in proximity to the patient) is not the only important factor. Multiplexing is also a key factor, particularly for those who are symptomatic. It is critical that the cause of the symptoms be determined as early as possible without the need for re-testing. When a COVID-only test returns a negative result on an individual who is symptomatic, the healthcare provider and patient wonders if the result was a false negative for COVID or if the symptoms are being caused by a different pathogen. There are about 20 pathogens that can cause respiratory illnessso getting a negative result on a person who is symptomatic is not uncommon when using a single-plex test during the middle of cold and flu season. Many clinicians, patients, epidemiologists, and public health officials want technology that provides a positive identification of the cause of symptoms, but the unwillingness of insurance companies to cover more of the higher cost of multiplex tests has presented a barrier to more widespread adoption.

 

Promote Open-Access POC Technology

The most important requirement to modernize our POC testing solutions for pandemic prevention is to promote POC systems that are “open access”. Open-access POC systems are microfluidic and draw reagents from bulk reservoirs that hold enough material to perform many tests. The most useful open-access systems utilize real-time PCR chemistry, which is considered a gold standard chemistry and is manufactured by many vendors worldwide. The abundance of manufacturers means new tests can be synthesized at scale very quickly and shipped at room temperature to any location needing new tests.

New R&D quality tests can be loaded into open-access POC systems within 1-2 weeks of initial pathogen identification, rather than ~8 weeks which is more typical for manufacturers of today’s “closed-access” POC systems. Adopting such a strategy would represent a significant paradigm shift in FDA regulatory policy for IVDs, but this shift does need to happen to improve our defenses. In essence, once the FDA approves an open-access PCR system for human diagnostics, in light of a new threat, the FDA would require minimal validation of an R&D test prior to shipping the test to facilities operating open-access systems.

To my knowledge, the FDA has never received an application to use an open-access multiplexed POC system for clinical diagnostics. So, they have not yet had the opportunity to weigh in on the concept of allowing an R&D quality test to be automated in a POC system. When designed by experts, the quality of R&D tests can be exceptional with a great likelihood of success. Furthermore, their use on open-access platforms would only be transient, as R&D quality tests would be replaced with validated tests as soon as they are available. This concept is being presented under the assumption that any R&D test being automated at the POC is one that is added on top of a panel of tests that have already been validated. As such, a POC additional open-access test should only be viewed as a positive, as having no test at all provides a 100% guarantee that a novel pathogen or variant cannot be detected at the point of care quickly. Having federal officials accept and embrace the utility of rapidly configuring open-access multiplex tests at the POC would be a sea change from the currently enforced policy.

Because of the ease of getting new test chemistry onto open-access systems, they are much better suited to respond to a mutated virus than a closed-access system. It is critical to be able to respond to any new mutation, whether it affects the sensitivity of the test or whether it represents a new variant that has clinical significance, such as the United Kingdom (B.1.1.7), South African (N501Y.V2 variant or B.1.351), Brazilian (P.1), and Santa Clara (L452R) strains (Figure 1).3,4,5

 

Stopping the Spread of COVID Variants and New Pathogens

Emerging SARS-CoV-2 variants of concern
Figure 1: Emerging SARS-CoV-2 variants of concern.

These variants are currently detected by next-generation sequencing surveillance efforts, which need to be more common. Once a novel pathogen’s sequence is known, R&D versions of real-time PCR tests can be designed, manufactured, tested against synthetic targets of the novel pathogen, and shipped to locations operating open-access multiplex POC testing solutions within 1-2 weeks’ time.

We must remember that SARS-CoV-2 will not be the last pathogen to affront an attack on humanity. We have been lucky to avoid a respiratory disease like COVID-19 for such a long time, as we’ve had plenty of close calls with other respiratory outbreaks (e.g., SARS, MERS, and avian influenza H5, H7, and H9 subtypes).6 Of note, there have been other deadly epidemics such as HIV and Ebola, but because these are spread by direct contact with blood or other bodily fluids, this fundamentally slows transmission. It is really just the respiratory pathogens that present the gravest threat for high numbers of deaths over a relatively short time frame.

To give you a sense of how often new pathogens emerge, the CDC published a report summarizing that nine new germs were either introduced or emerged in the United States between 2004 and 2016.7 This should serve as a reminder that the microbial onslaught is constant, so we must improve our defenses and remain ever vigilant.

The government cannot wait and must immediately work aggressively to modernize our disease surveillance infrastructure. Ideally, this effort should promote the massive deployment of POC molecular tests and aim for a significant number of these to be open-access multiplexed systems. The government needs to push standards to have these molecular POC testing solutions automatically report de-identified data to surveillance networks, so we can avoid the delays caused by manual reporting.

 

Pandemic Prevention

 

When the COVID-19 pandemic begins to wane, the government needs to continue to support advancements in POC testing until these instruments become omnipresent. The end goal is to have automated open-access, highly multiplexed, POC testing solutions that are deployed widely.

The CDC and FDA should also ‘fire drill’ the entire surveillance system by simulating a novel pathogen to test our ability to bring new tests to the POC across the country in a reasonable time frame. This will highlight any weaknesses that need to be addressed to maximize our chances of successfully containing the next Disease X.

If any one of these features is missing, we will continue to be more vulnerable than necessary to new microbial threats, whether naturally-derived or bio-engineered by a terrorist.

 

Related blog post: What is qPCR?

 

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https://coronavirus.jhu.edu/map.html
https://en.wikipedia.org/wiki/Influenza-like_illness
https://www.cdc.gov/coronavirus/2019-ncov/transmission/variant.html
https://deadline.com/2021/01/another-new-covid-19-variant-in-l-a-vaccine-resistant-denmark-1234675834/amp/
https://jamanetwork.com/journals/jama/fullarticle/2776039
6 https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm
7 https://www.cdc.gov/media/releases/2018/p0501-vs-vector-borne.html

 

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