The novel coronavirus that’s sickening thousands globally—and at least five people in the United States—is driving countries to close their borders and Americans to buy up surgical masks quicker than major retailers can restock them.
There’s another virus that has infected 15 million Americans across the country and killed more than 8,200 people this season alone. It’s not a new pandemic—it’s influenza.
The 2019-2020 flu season is projected to be one of the worst in a decade, according to the National Institute of Allergy and Infectious Diseases. At least 140,000 people have been hospitalized with complications from the flu, and that number is predicted to climb as flu activity swirls.
The flu is a constant in Americans’ lives. It’s that familiarity that makes it more dangerous to underestimate, said Dr. Margot Savoy, chair of Family and Community Medicine at Temple University’s Lewis Katz School of Medicine.
“Lumping all the viral illness we tend to catch in the winter sometimes makes us too comfortable thinking everything is ‘just a bad cold,'” she said. “We underestimate how deadly influenza really is.”
Even the low-end estimate of deaths each year is startling, Savoy said: The Centers for Disease Control predicts at least 12,000 people will die from the flu in the United States every year. In the 2017-2018 flu season, as many as 61,000 people died, and 45 million were sickened.
In the 2019-2020 season so far, 15 million people in the United States have gotten the flu and 8,200 people have died from it, including at least 54 children. Flu activity has been elevated for 11 weeks straight, the CDC reported, and will likely continue for the next several weeks.
Savoy, who also serves on the American Academy of Family Physician’s board of directors, said the novelty of emerging infections can overshadow the flu. People are less panicked about the flu because healthcare providers “appear to have control” over the infection.
“We fear the unknown and we crave information about new and emerging infections,” she said. “We can’t quickly tell what is truly a threat and what isn’t, so we begin to panic—often when we don’t need to.”
The Flu Can Be Fatal
Dr. Nathan Chomilo, an adjunct assistant professor of pediatrics at the University of Minnesota Medical School, said that the commonness of the flu often underplays its severity, but people should take it seriously.
“Severe cases of the flu are not mild illnesses,” Chomilo said. “Getting the actual flu, you are miserable.”
The flu becomes dangerous when secondary infections emerge, the result of an already weakened immune system. Bacterial and viral infections compound the flu’s symptoms. People with chronic illnesses are also at a heightened risk for flu complications.
Those complications include pneumonia, inflammation in the heart and brain, and organ failure—which, in some cases, can be fatal.
Chomilo, an internist and pediatrician for Park Nicollet Health Services, said this flu season has been one of the worst his Minnesota practice has seen since the H1N1 virus outbreak in 2009. Some of his patients, healthy adults in their 30s, have been sent to the Intensive Care Unit, relying on ventilators, due to flu complications.
The Virus Is Always Changing
Influenza is tricky because the virus changes every year. Sometimes, the dominant strain in a flu season will be more virulent than in previous years, which can impact the number of people infected and the severity of their symptoms.
Most of these changes in the virus are small and insignificant, a process called antigenic drift.
Occasionally, the flu undergoes a rare antigenic shift, which results when a completely new strain of virus emerges that human bodies haven’t experienced before, she said.
Savoy compares it to a block party: The body thinks it knows wh0—or in this case, which virus—will show up, and therefore, which virus it needs to keep out. But if a virus shows up in a completely new getup, it becomes difficult for the body’s “bouncers”—that’s the immune system—to know who to look for and keep out. The stealthy virus can infiltrate easily when the body doesn’t recognize it.
This flu season, there’s no sign of antigenic shift, the most extreme change. But it’s happened before, most recently in 2009 with the H1N1 virus. It became a pandemic because people had no immunity against it, the CDC reported.