Still Learning: Optimizing the Diagnosis and Screening of Respiratory Viruses

The CDC reported historically low influenza rates in the US during the 2020-21 flu season. Although the data were welcomed news for medical communities, there remains great uncertainty as to whether the pattern will repeat for the upcoming fall and winter months.

And with COVID-19 restrictions currently in flux across the US, there is worry among healthcare experts that the circulation of influenza strains and other communicable diseases will spike.

One question rings out in the face of these valid concerns: Are we prepared?

In the context of combating communicable diseases, preparedness can be defined as ensuring the proper infrastructure and protocols are in place for diagnostics, surveillance, and timely responses to positive tests.

While the burdens of the pandemic have crippled communities and strained institutional resources, these very challenges have likewise spurred enhancements in testing and diagnostic capabilities across the country—to a degree, at least.

The hope, then, is that lessons learned this past year—and the resources developed to combat COVID—may help set a new standard for diagnosis and surveillance of flu-like viruses.These strategies should include accurately differentiating virus strains, targeting at-risk communities in testing programs, and responding to infections in meaningful ways.

Of course, surveillance and diagnostic technologies must keep up with the evolving public health needs.

This last year, mired in failed response to COVID-19 outbreaks, has only exposed the significant shortcomings in the country’s healthcare system and pandemic preparedness. While the medical community—and the public, for that matter—have a firmer grasp of the importance of widespread, accurate diagnostics, there remain glaring holes in these aforementioned strategies.

The Impact of COVID on Diagnostics

Testing accessibility, timeliness, and accuracy for COVID-19 has drastically improved since early 2020. The previous standard of nearly a weeks’ time turnaround for test results has at least halved, as reliable clinical- and home-based assays have boomed in availability.

Kust as widespread and efficient testing is foundational to viral surveillance, accurate identification of variants is similarly essential to providing a clear picture of viral prevalence.

“[COVID-19] has brought attention to the notion of the varieties of respiratory infections that are out there,” William Schaffner, MD, Professor of Preventive Medicine and Health Policy at Vanderbilt University School of Medicine, told Contagion®.

He explained that the increasing circulation of the delta variant—as well as the initial circulation of the alpha variant last year—has only enhanced widespread awareness and appreciation of the nuances in surveillance.

“A new virus on the scene, with its variants, really has implications for what we can do—both from a public health perspective and a clinical perspective,” he said.

Of course, awareness of these nuances and the need to better understand them is only one piece of the puzzle when it comes to diagnostics and screening.

In response to the immediate and pressing emergencies during the early days of the pandemic, individual clinicians have increasingly gained tools that can more readily make accurate diagnoses, treat patients, and offer preventative strategies.

Schaffner noted that multiplex tests, which can more accurately differentiate between flu strains, are slowly, but surely reaching refinement.

However, these technological refinements have defined the evolution of respiratory viruses over the past decade, prior to the onset of the COVID-19 pandemic. For example, rapid influenza molecular assays with high sensitivities and specificities have been developed that can detect virus—and sometimes discriminate between strains—quickly.

Rapid influenza diagnostic tests (RIDTs) allow for quicker detection of both influenza A and B viruses, but the ability to further identify the subtypes of influenza viruses is limited.

In July of 2020, the US Food and Drug Administration (FDA) authorized the use of the CDC Flu SC2 Multiplex Assay, a single test able to differentiate between SARS-CoV-2, influenza A, and influenza B.

Despite ongoing advancements, the technology still does not meet the high demands for quick, accurate, and comprehensive testing, Schaffner argued. The rapidly evolving demands of the public have largely overburdened—and exposed—the shortcomings in the current technological capabilities.

Saskia Popescu, PhD, Assistant Professor in George Mason University Schar School of Policy and Government ’s Biodefense Program, echoed Shaffner’s sentiment, offering additional insight into current diagnostic limitations.

“Doing genomic sequencing for SARS-CoV-2 strains has been a bit challenging as only a small percentage of samples undergo this,” she told Contagion. She further stressed that the technology should be expanded to better clarify the precise viral circulations within and across communities.

“In general,” Popescu continued, “we need more point-of-care access for respiratory viruses and the ability to develop/deploy these for novel pathogens.”

Furthermore, she said, many hospitals have long lacked resources for contact tracing and infection prevention, a gap that cannot be overlooked as more respiratory viruses begin to circulate in the colder months.

That is all to say, then, that the pandemic has simultaneously underscored the importance of rapid, accurate testing and lain bare the discrepancy between public health needs and available technological resources.

Diagnostics and Testing: Staying Grounded

The story of the COVID-19 pandemic is largely the story of shortcomings, limitations, and discrepancies in healthcare. When looking at the current state of diagnostics and testing, one can see both a booming field prodded by the ongoing public health crisis and a barely passing report card on the field’s ability to meet demands.

While the past year has shone a spotlight on ever-increasing and circulating viral strains, and while the idea of utilitarian responses to positive tests has become more widely accepted, general diagnostics and its advancements will continue to fall short so long as testing remains inaccessible to large swaths of the public.

For Schaffner, the need to lower the costs of tests is paramount. As technology catches up to address these nuances in respiratory infections, it is similarly important to ensure that both clinics and patients have financial access to newer resources as they become available.

Perry Halkitis, PhD, of the Department of Biostatistics and Epidemiology at Rutgers School of Public Health, pointed to the limitations that still exist for medically underserved communities.

Much of Halkitis’ work has largely focused on the HIV/AIDS epidemic—and yet, it is this perspective that has informed the lens through which he views the healthcare of communicable diseases.

“We have to bring healthcare to people,” Halkitis stressed. “We can’t expect people to come to healthcare.”

Offering testing as an accessible healthcare resource would not only help bolster large-scale surveillance efforts but also help develop actions to control spread in at-risk communities.

Additionally, Halkitis noted that surveillance and screening can only work so long as individuals are willing and able to get tested. In particular, he highlighted the barriers caused by fear of testing—and treatment—which can ultimately cause mistrust to fester between communities and providers (and, consequently, low testing rates).

And so, addressing fears and educating the public in a way that is empathetic and thoroughly understanding of human behaviors is an integral, although often overlooked, facet of improving and keeping up with rapidly changing diagnostic strategies.

From this Vantage Point: Diagnosing Respiratory Viruses

The COVID-19 pandemic has forced public health experts to grapple with the chasm between what is needed to prevent next the pandemic and the resources and technologies that are available to prevent it.

Technologies and practices for respiratory viruses diagnostics will constantly undergo refinement—and pandemics will inevitably play a role in this refinement process. On the other hand, unless access to care is prioritized, disparities in testing and surveillance will continue to persist.

As Schaffner explained, the pandemic has illuminated the risks and realities of respiratory viruses. It has been a stress test on hospital and clinic resources, revealing the shortcomings across the healthcare spectrum. Worse yet, the pandemic continues to underscore the fact that what is being done for preventative measures is simply not enough.

Diagnostics and testing for COVID-19 has certainly ramped up over the past year, but it remains to be seen whether new strategies and technologies will pay off for other respiratory viruses. Although the pandemic is far from over, perhaps the lessons learned from this past year will have a noticeable, positive impact across other communicable diseases.

“We Americans have a very short attention span,” Schaffner said. “There’s always the new frontier. We look to the future much better than we look in the past—and we frequently forget our lessons.”

And part of these lessons includes looking back on these past months through clear, serious eyes so that new, worthwhile technologies and policies may be implemented or refined in the most efficient, cost-effective, and accessible way possible.

Nonetheless, many experts see that as a great hurdle yet to be overcome.