Prepping for COVID-Flu Triage as Flu Season Begins

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The patient was asked a series of questions about exposure to SARS-CoV-2 before he came into the clinic. He professed no exposure. Once in the office, he told a nurse that he now recalled he'd been around a friend who had recently tested positive. The patient was alsohaving symptoms that indicated possible infection.

The nurse immediately left the room and came back in full personal protective equipment (PPE) to test him. But results weren't expected for days, which meant that multiple exposures could occur in the meantime.

That situation has been playing out in physician offices for months and likely will be repeated multiple times over as influenza season starts, said Jacqueline W. Fincher, MD, an internist in Augusta, Georgia, who had that patient in her office.

"The big issue going forward is what the volume is going to be," Fincher, president of the American College of Physicians (ACP), told Medscape Medical News.

Patients often don't mention symptoms during screening calls, said Gary LeRoy, MD, FAAP, a family doctor at a federally qualified health center in Dayton, Ohio. But the unrelenting presence of COVID-19 creates anxiety, he said. Patients might be in for diabetes but ask, "Can you check me for COVID?" LeRoy, president of the American Academy of Family Physicians (AAFP), said in an interview with Medscape Medical News.

The set-up for primary care physicians this winter is looking worrisome.

"The worst case is that you have high co-circulation of both SARS-CoV-2 and the flu, and you're using a lot of the same reagents and supplies for both of those pathogens and you run into supply chain issues or capacity issues at individual laboratories because of testing volume," Kelly Wroblewski, director of infectious diseases at the Association of Public Health Laboratories, told Medscape Medical News.

And Wroblewski doesn't foresee any improvement soon. "Through the end of the calendar year, we are expecting an uncomfortably tight supply chain," she said.

With predicted shortages and rapid COVID-19 tests not always available, clinicians may have to get creative.

Will Rapid Tests Help?

Physicians will want to quickly determine if a patient's symptoms are due to influenza or SARS-CoV-2.

"It sure would be nice to have that point-of-care rapid COVID test because you can tell that patient right then, 'You need to quarantine for 10 to 14 days,' " said Fincher.

But front-line physicians aren't likely to have an infinite supply of rapid COVID-19 tests at their disposal. Nursing homes, universities, large employers — like those in food production — and others are seeking the same tests.

The US Food and Drug Administration (FDA) has granted emergency use authorizations (EUAs) for four rapid, point-of-care antigen tests that detect fragments of SARS-CoV-2 in the nasal cavity. The tests are generally less sensitive than the gold standard molecular tests that use polymerase chain reaction (PCR) to measure viral DNA or RNA, according to the AAFP's COVID-19 testing guide. The antigen tests may also result in false negatives, said the AAFP.

In late August, the FDA granted an EUA for Abbott Laboratories' BinaxNOW COVID-19 Ag Card, which takes 15 minutes to deliver results and costs $5, according to the US Department of Health & Human Services (HHS).

HHS paid Abbott $760 million for 150 million tests. It is shipping those to nursing homes, congregate facilities, historically black colleges and universities, and states. HHS hopes states will use them for children in kindergarten through grade 12.

HHS Assistant Secretary Brett Giroir, MD, who leads the government's COVID-19 testing efforts, said that rapid-antigen test makers are tripling production. But the government will not facilitate COVID-19 or other test distribution to private physicians, Giroir told Medscape Medical News.

They will be able to get point-of-care tests "through their normal distribution channels, so we are not going to interfere with that," he said.

Rapid COVID-19 tests will soon be widely available, predicted Giroir. "We've also reviewed the orders for them, and they will be going heavily to primary care, which was their primary market before COVID," he said.

LeRoy, however, was skeptical. "The use of these tests is an individual practice choice based on availability, cost, and safety," he said.

COVID-19 Triaging Even More Critical

With the COVID-19 testing landscape unclear, physicians are considering other strategies. Vaccination is one means of keeping a lid on the spread of influenza. AAFP recommends a further ramping up of triage schemes aimed at keeping potentially infected patients out of the office.

"Many of us are not inviting people to come in to find out whether they have flu or COVID-19," said LeRoy.

Primary care physicians have been at heightened risk, as patients seem to prefer going to their doctors to see if they have COVID-19, he said.

In March and April, he did not have COVID-19 tests or enough PPE. "We couldn't get our hands on the doggone tests, no matter how hard we tried," he told Medscape Medical News, noting that big-volume purchasers were in line ahead of physicians and clinics. "We don't buy millions of the tests, we buy maybe hundreds," said LeRoy.

His office screens patients with questions about potential exposures and symptoms. If their temperature is higher than 100.4°F at the door, they are not allowed into the office, but are triaged there and sent to an alternative place where they can be tested for flu or COVID-19.

Fincher has a similar protocol. Patients who report acute illness or exposure by phone might be converted to a telemedicine visit or told to come to the thrice-weekly acute respiratory clinic for testing.

This fall and winter, "as much as possible, we want to take flu off the table," Fincher said. "If we don't have enough test kits for COVID, and if we don't have a turnaround time that is reasonable, like within 3 days," she said, "it becomes irrelevant."

CDC: Treat Flu Empirically

Neither AAFP nor ACP plan to issue new guidance on influenza and COVID-19. LeRoy said AAFP looks to the World Health Organization, Centers for Disease Control and Prevention (CDC), and state health departments to inform its recommendations.

The CDC updated its guidance on use of antivirals in influenza in late August, which included a section on differentiating flu and COVID-19. The agency urged physicians to steer patients with acute respiratory illness to telemedicine.

For outpatients with suspected influenza, clinicians "can consider starting early (≤ 48 hours after illness onset) empiric antiviral treatment," said the agency, even if the patient was not seen in the office.

"Clinicians should not wait for the results of influenza testing, SARS-CoV-2 testing, or multiplex molecular assays that detect influenza A and B viruses and SARS-CoV-2 to initiate empiric antiviral treatment for influenza" in priority groups, which include patients who are hospitalized, have severe, complicated, or progressive illness, or are at higher risk for flu complications.

The CDC cautioned that a positive SARS-CoV-2 test does not preclude influenza infection, and that a positive flu test does not preclude SARS-CoV-2 infection.

The FDA issued an EUA in July for a CDC multiplex molecular diagnostic that can detect and differentiate SARS-CoV-2 and influenza A and B. But the PCR-based test must be conducted in a lab certified under the Clinical Laboratory Improvement Amendments (CLIA) and will require many of the same supplies that have been experiencing shortages.

Two manufacturers, BioFire Diagnostics and Qiagen, have received EUAs for PCR-based diagnostics that detect multiple pathogens, including SARS-CoV-2 and other coronaviruses, and influenza A and B.

LeRoy said he worries about the cost of multiplex tests. "If the population at most risk can't afford the test, that's misplaced resources," he said.

Wroblewski said testing should be driven by the individual's history and what's happening in a given geographic area.

"If you have respiratory symptoms and you have no known exposure to somebody with flu or somebody with COVID, I think you want a multiplex test," said Wroblewski. But if the patient's child has the flu, then a flu test will be fine, she said. If an area has high COVID-19 case rates, the SARS-CoV-2 diagnostic is probably sufficient.

"We're going to have to be kind of nimble as we go through this respiratory season and responsive to which viruses are circulating," she said.

'No Excuse' for Lack of Tests

The public health labs — which provide "situational awareness" to state health officials and clinicians about public health threats — are also planning for how to deal with potential testing shortages, Wroblewski said.

Much of the focus for those labs is on prioritizing how much testing will be multiplex and which patients should get those tests, she said.

But physicians are not optimistic. The ACP took matters into its own hands for the lack of PPE by bulk purchasing for small practices. But it can't replicate that for diagnostics, said Fincher. She said it would be great if the federal government stepped in and ensured the testing supply is adequate.

With the advent of the Abbott tests, "it is definitely getting significantly better," Fincher said.

But, she added, "There's just really no excuse why we don't have enough tests. There's just not."

Alicia Ault is a Lutherville, Maryland-based freelance journalist whose work has appeared in publications including Smithsonian.com, the New York Times, and the Washington Post. You can find her on Twitter @aliciaault.

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