This Shocking Thing Could Happen When COVID Meets the Flu

The seasonal flu has the power to double the transmission rate of COVID-19, says new study.

If you're still wondering whether or not to get a flu shot this year, consider the findings of an eye-opening new study out of Europe. Teams of researchers across two countries analyzed health data from the early days of the pandemic to try and better understand how the spread of COVID-19 was influenced by the seasonal flu. Ultimately, they concluded that the flu "was associated with an average 2 to 2.5-fold population-level increase in SARS-CoV-2 transmission." In other words: The flu was responsible for potentially doubling the transmission rate of COVID-19.

The study even argued that the leveling of COVID-19 cases in the spring wasn't entirely due to proper social distancing, lockdown measures, and face masks. The researchers argue that the end of flu season played a major role there, as well.

"The results were unequivocal," said the study, which was conducted by the Max Planck Institute, in Germany, and the Pasteur Institute, in France. "[They] suggest the need to increase vaccination against influenza, not only to reduce the burden due to influenza viruses, but also to counteract their facilitatory impact on SARS-CoV-2."

In the United States, health officials warn of the "twindemic" largely because they fear that a rise in flu cases will overwhelm hospitals. Also, of course, they fear what will happen if people are exposed to two dangerous respiratory illnesses simultaneously. "You can certainly get both the flu and Covid-19 at the same time, which could be catastrophic to your immune system," Adrian Burrowes, MD, told CNN. Both illnesses could be worse for your lungs and other organs than simply having one of them, doctors say.

But the new data out of Europe, if accurate, shows how much the coronavirus may have relied on flu season—a cold-weather time of year with people indoors and inhaling and exhaling the same air—to spread farther among the population.

To reach their calculation, the European team used "state-of-the-art statistical inference methods" to create a "population-based" model that simulated the "co-circulation" of COVID-19 and the seasonal flu in four European countries (Belgium, Italy, Norway, and Spain). From that model they were able to calculate the total impact that the flu had on the spread of the coronavirus.

The report is yet another grim warning to us all as the seasons begin to change. As Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said during a panel discussion at Harvard University last week, "We need to hunker down and get through this fall and winter, because it's not going to be easy." But getting a flu shot could help make things easier. And for more important knowledge of the coronavirus, make sure you know the 98 COVID-19 Symptoms Everyone Should Know.

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