The flu can mean a trip to the hospital or a doctor, or at least a miserable week on the sofa. So why would the University of Maryland ask people to come to Baltimore just to expose themselves to the nasty bug?

For all the cases of influenza, and there are a ton this time of year, researchers don’t really know how it’s transmitted. They’re aiming to find out with a first-of-its-kind experiment.

“Viruses can be transmitted in different ways,” said Dr. Wilbur Chen, the study co-investigator at the University of Maryland School of Medicine, which is partnering with the university’s school of public health. “Some might be more airborne than others.”

With flu, it’s long been thought people got infected when someone already sick sneezed or coughed big droplets with lots of virus on them, or they touched a surface like a doorknob that harbored the virus. That’s likely true, but the researchers suspect something more.

They believe the main mode of transmission is tiny particles that float in the air after an infected person merely breathes or talks. That would be more like measles, a really contagious virus.

To test the idea, they have so far recruited eight healthy people aged 18 to 59 through advertising and a university registry of volunteers. They come from an area spanning from Northern Virginia to New Jersey. Seven others tested positive for COVID-19 and were sent home.

They now begin the process of finding an “index” flu case, someone who has tested positive within about 48 hours of the onset of symptoms. They are being recruited through hospitals, urgent care centers and advertising.

The volunteers will be holed up for up to two weeks in a sealed off floor of the Lord Baltimore Hotel where they will mingle as special sensors take a bunch of air quality measures.

If it sounds a little bonkers, it may be because it’s never been done before — at least not like this. Some of the same researchers participated in a study about 10 years ago where flu virus grown in a lab was swabbed into people’s noses. Chen said it just didn’t transmit virus all that well and didn’t explain how it could transmit on its own.

Chen couldn’t name a similar transmission study that involved researchers monitoring for natural transmission of a virus.

So-called challenge studies, where people are purposefully infected in the name of science, have been conducted before.

The World Health Organization policy supports their use for vaccine development, for example, so long as they are “conducted within an ethical framework in which truly informed consent is given,” plus there is a lot of “forethought, caution and oversight.” And importantly, WHO says, the information gained justifies the risks.

The National Institutes of Health has given its stamp, and $15 million, to the Maryland researchers for the flu study.

Researchers at Maryland say that given the burden of the flu, they are on solid ground here. According to the U.S. Centers for Disease Control and Prevention, an estimated 21,000 Americans died last year from infections, 360,000 were hospitalized and 31 million were infected. Plenty of seasons have been worse.

Dr. Donald Milton, the principal investigator from the school of public health, said the results can be used to update public health policy. That could mean changes in masking advice and improved air quality, which could prevent transmissions of a lot of viruses.

“We hope to clearly define how flu is transmitted, which will allow us to set better policy,” Milton said in an interview recorded by the university. “It could lead to policies to improve air quality in schools, homes and places people catch the flu.”

As for those volunteers, room and meals are covered at the hotel, and they will be paid up to $1,900 each. Medical attention will also be provided.

In a recorded interview, Mathew Tan said he volunteered because he had previously been “bedridden, with body aches, chills, you name it” from the flu. And his main preventive measure of distancing himself from those clearly sick didn’t work.

“This was an opportunity to see how such a study was being conducted,” said Tan, a 45-year-old gig worker from Gaithersburg.

Chen said volunteers don’t need to have any such reason. They may just like the idea of some paid days in a hotel where they can work remotely or just relax. And hey, they may not even get sick (though the researchers are eager to see if they do.)

The study will continue until March. Flu sufferers interested in volunteering can call: 410-706-8800.