Epidemiologists warn that elderly and other individuals may be at high-risk for co-infection by strains of both SAR-CoV-2 and influenza

As of October, the influenza (flu) season has begun in North America. With the COVID-19 pandemic still prevalent, clinical laboratories must be prepared not only for increased demand for SARS-CoV-2 tests, but also for an increased number of orders for flu tests as well. In fact, virologists are sounding the alarm that some patients may present with an uncommon double infection of both viruses.

The potential for contracting the co-infection was dubbed “flurona” by the Israeli Outbreak Management Advisory Team in 2020. The Israeli Team coined the term flurona to describe the potential of contracting both COVID-19 and influenza after two young Israeli pregnant women were diagnosed with influenza and COVID-19. Since then, cases of co-infections have been confirmed in multiple countries around the world, according to The Washington Post.  

The symptoms of influenza and COVID-19 are extremely similar. According to the Centers for Disease Control and Prevention (CDC), symptoms for both influenza and COVID-19 include fever, cough, chills, sore throat, and body aches. However, without a clinical laboratory test it is nearly impossible to distinguish one virus from the other.

Therefore, during this cold and flu season, clinical laboratory testing will be extremely important. And though co-infection with COVID-19 and the flu is rare, lab leaders should be on the lookout for spikes in testing.

Stephen McMullan, MD

“Co-infection is rare with COVID-19 and the flu, or COVID-19 and other types of infections that you might get as far as upper respiratory infections, because COVID-19 tends to take over,” Stephen McMullan, MD, a Mayo Clinic family medicine physician, told Mayo Clinic News. “Once COVID-19 is in your body, it’s going to be the predominant virus, but there are some rare cases where we have seen people getting both COVID-19 and the flu. So, it is possible, but it’s certainly not common.” Clinical laboratories should prepare for a spike in viral infections this winter that could indicate flurona. (Photo copyright: Mayo Clinic.)

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What Exactly Is a Flurona?

Although it is possible—albeit rare—to contract the flu and COVID-19 at the same time, flurona does not appear to be a “twindemic,” nor is it a distinct disease or a mutation of the two viruses, The Washington Post reported.

“The name seems to suggest that the viruses have somehow combined—and that’s not the case. It’s just that a person may get infected with two respiratory viruses at the same time or in short succession,” epidemiologist Judith O’Donnell, MD, Director, Department of Infection Prevention and Control, and Section Chief, Division of Infectious Diseases at Penn Presbyterian Medical Center, told an NPR affiliate in Pittsburg.

“It’s rare, but it’s not surprising that during a typical influenza season—which here in the northern hemisphere is right now during the winter months—that you will see multiple respiratory viruses circulating at the same time, and that people can get infected with more than one respiratory virus at the same time,” she added.

Though flurona may not be a hybrid virus, that does not mean it is of no concern.

“Although a low proportion of COVID-19 patients have influenza co-infection, the importance of such co-infection, especially in high-risk individuals and the elderly, cannot be ignored,” wrote the authors of a study published in Frontiers of Medicine titled, “COVID-19 and Influenza Co-infection: A Systematic Review and Meta-Analysis.”

Did COVID-19 Lockdowns, Social Distancing Cause Flurona?

According to the Washington Post, the US had record lows of influenza during the 2020-2021 flu season, however this was likely due to lockdown measures. With lockdown measures and social distancing even less prevalent this flu season, there is a risk of individuals being at risk for multiple respiratory viruses.

“We’re all a little bit more back together than we were a year ago,” McMullan told Mayo Clinic News. “The kids are back in school, and we have more events that people are attending, which could explain why we’re seeing flu cases rise.”

Thus, clinical laboratories should prepare for not only a higher number of flu tests, but also COVID-19 tests as well. That is because patients will not be able to distinguish which virus they are sick with based on symptoms alone. Further, because COVID-19 and the flu have similar symptoms, individuals may seek out multiple tests, or test for one virus and not the other.

McMullan asserts that a co-infection of the flu and COVID-19—though rare—is not impossible. For the best chance to avoid both diseases he suggests high-risk individuals “Get vaccinated against COVID-19, including your booster if eligible, and make sure to get your flu vaccine, continue to do the same strategies to protect yourself and others, such as wearing a mask in high-risk situations, washing your hands, and staying home if you feel ill.”

Meanwhile, clinical laboratory managers will want to track developments during this flu season. For example, flurona may be uncommon at this time, but emerging variants of SARS-CoV-2 and different strains of influenza might increase the number of patients diagnosed as infected with both COVID-19 and influenza.

Ashley Croce

Related Information:

What Is ‘Flurona’? Israel Reports First Case of Rare Double Covid and Flu Infection

Similarities and Differences between Flu and COVID-19

What Is ‘Flurona’ and Why a Mayo Clinic Expert Says Flu Cases Are Rising

What Is ‘Flurona’? Coronavirus and Influenza Co-Infections Reported as Omicron Surges

CDC: COVID Data Tracker Weekly Review

The Double-Whammy COVID-Flu

What to Know about ‘Flurona’

Getting COVID-19 and the Flu at the Same Time: What Are the Risks?

Rates of Co-infection Between SARS-CoV-2 and Other Respiratory Pathogens

AHA: Flurona and Its Impact on Flu Season

COVID-19 and Influenza Co-infection: A Systematic Review and Meta-Analysis

What Is ‘Flurona’? Why Are People Talking about It Now?

Fact Check-‘Flurona’ Is Not the Name of a New SARS-CoV-2 Variant

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