Can you have the flu and coronavirus at the same time?

In March, Dr. Chelsea Park spiked a fever and had chills with a cough and a sore throat, according to CBS 11, Dallas-Fort Worth. The internal medicine doctor suspected she had the flu, but to be safe she also received a COVID-19 test. While the flu diagnosis was unsurprising, she was floored to learn she also had COVID-19.

"I'm thinking that it's not very common," Park told CBS 11. "I turned out to be one of the those few lucky ones." TODAY reached out to Park to learn more about her experience, but she declined an interview.

Experts support her thoughts, there have been only a few cases of people with both flu and COVID-19.

How common is it to have both the flu and COVID-19?

"It's very unusual. There has been a handful or less of such instances reported," Dr. William Schaffner, an infectious disease professor at Vanderbilt University in Nashville and medical director of the National Foundation of Infectious Diseases, told TODAY. "We would anticipate that, if anything, you're likely to get more severe disease."

When COVID-19 tests weren't readily available, doctors often tested people for other illnesses first.

"If you were to test first for flu and the flu was positive you would not test further," Schaffner explained.

It could mean that some cases of people who had flu and the coronavirus were not captured. And, when COVID-19 started spreading in the United States, flu season was winding down.

It is possible that since both flu and the coronavirus are respiratory viruses that spread in similar ways, people don't often have them at the same time. Early reports from China indicated that people only had COVID-19 with no other infections, Dr. David Cennimo, an infectious disease expert at Rutgers New Jersey Medical School in Newark, explained. That's likely because at the epicenter of the outbreak, the novel coronavirus dominated the infections.

Yet a recent paper in JAMA found that in the United States about 20% of patients had a viral infection in addition to the coronavirus. Still, a combined coronavirus and flu infection are rare (the paper mentions one case, he said).

"We don't know if someone would do worse infected with both viruses at the same time, but it is certainly possible," Cennimo told TODAY. "From a public health standpoint, it's going to be really important to try to minimize the cases (of influenza)."

What testing might look like in the fall

It's hard to predict exactly what virus testing will look like this flu season, but Cennimo suspects that some commercial tests might bundle services.

"It will be one swab test for multiple viruses," he forecasted. "If nothing else changes, the prudent thing would be testing for both of these very contagious viruses that have a very similar clinical presentation."

Schaffner also expects more screening for both viruses, which likely will lead to increased reports of co-infection.

"There will be much more testing both for flu and for COVID," he said. "We anticipate that there will be more cases found."

Get your flu vaccine in the fall

Experts are urging everyone to receive a flu vaccine when they become available in the fall.

"It's always important to get vaccinated against the flu but this year more than ever," Schaffner said. "We anticipate both viruses being out there. Let's do everything we can to protect ourselves with the vaccine."

Some people balk at getting the flu vaccine because they worry it will give them the flu or it won't protect fully from the flu. While it's "imperfect," the flu shot cannot give you the flu, and it prevents people from developing serious complications that require hospitalization or can lead to death.

"The people that you see infected post-vaccine, the vast majority do significantly better," Cennimo said. "They're only sick for a few days. They're not the ones that went to the hospital They're not the ones with severe pneumonia. So what you're dealing with the vaccine, in some cases, is changing a potentially life-threatening infection into an inconvenience."

Having a milder version of the flu — or never getting it at all — keeps people away from doctor's offices, emergency rooms and hospitals. This allows doctors to devote resources to helping patients with COVID-19.

"We would like to prevent as many hospitalizations from influenza as possible because there may well be a surge in hospitalizations for COVID," Schaffner said.

Mask wearing, proper hand washing and social distancing should lead to fewer cases of flu as well, but that's no substitution for a vaccine.

"All of those things will help reduce the transmission of both viruses because the two viruses are transmitted in an entirely similar fashion," Schaffner said.

The bottom line? People should protect themselves from the flu.

"There's value to the vaccine that prevents many illnesses completely and modifies or reduces the severity of many more cases," Schaffner said.