A deadly virus is spreading from state to state and has infected 15 million Americans so far. It’s influenza

In the 2019-2020 season so far, 15 million people in the US 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 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. That year’s flu vaccine is mostly effective in protecting patients in spite of these small changes, said Melissa Nolan, an assistant professor at the University of South Carolina’s School of Public Health.

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 who — 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.

Get your flu shot, experts say

To avoid complications from the flu, Savoy, Chomilo and Nolan have the same recommendation: Get vaccinated.

It’s not easy to tell how flu vaccination rates impact the number of people infected, but Savoy said it seems that the years she struggles to get her patients vaccinated are the years when more patients end up hospitalized with the flu, even if the total number of infections doesn’t budge.

Chomilo said some of his most frustrating cases of the flu are in patients who can’t be vaccinated because of preexisting conditions or their age (children under 6 months old can’t be vaccinated).

There are two important reasons to get the flu vaccine, he said — “Protecting yourself and being a good community member.”

Correction: An earlier version of this story misspelled Dr. Margot Savoy’s first name.