“You can certainly get both the flu and Covid-19 at the same time, which could be catastrophic to your immune system,” said Dr. Adrian Burrowes, a family medicine physician in Florida.
In fact, getting infected with one can make you more vulnerable to getting sick with the other, epidemiologist Dr. Seema Yasmin said.
“Once you get infected with the flu and some other respiratory viruses, it weakens your body,” said Yasmin, director of the Stanford Health Communication Initiative.
“Your defenses go down, and it makes you vulnerable to getting a second infection on top of that.”
Having both illness simultaneously “would increase the risk of longer-term effects of any of those organ systems,” said Dr. Michael Matthay, a professor of medicine and a critical care specialist at the University of California, San Francisco.
But it’s too early to know exactly how much worse that double whammy could be, compared to having each virus on its own.
That’s because Covid-19 didn’t spread across the US until near the end of the last flu season, Matthay said. So there’s not a lot of data yet on people who get both illnesses at the same time.
But Matthay suspects the potential for pneumonia would be greater if the body is infected with both the flu and coronavirus.
“The two (viruses) together definitely could be more injurious to the lungs and cause more respiratory failure,” he said.
Respiratory failure doesn’t necessarily mean your lungs stop working. It means the lungs can’t get enough oxygen into the blood.
How can I tell if I have Covid-19 or the flu (or both)?
“Symptoms of influenza and Covid-19 are pretty similar, so it’s difficult to distinguish the two,” said Dr. Leonard Mermel, medical director for the Department of Epidemiology and Infection Control at Rhode Island Hospital.
“Some people may have vomiting and diarrhea, though this is more common in children than adults,” the CDC said.
So the best way to know if you have the novel coronavirus or the flu (or both) is to get tested.