The flu could soon hit northeast parts of the country especially hard.
This year's season has already peaked but plenty of weeks remain and the level of cases that have been seen in the South are making their way up north.
The main strain of the flu this season is H1N1. The Center for Disease Control and Prevention said 41 states are reporting widespread flu outbreaks, and young adults are particularly vulnerable.
Yet while most people try to avoid the flu, some are getting paid thousands of dollars to get it.
A government study is paying individuals to become infected with influenza to research why some people are more immune to the flu even with a vaccine.
Volunteers are kept in isolation and they're symptoms are checked on a daily basis.
"I experienced a little head congestion, sinus pressure" Daniel Bennett, flu study volunteer, said.
"We can look at people, their immune system, and the flu and understand those interactions so that hopefully we can learn new information that could help us improve vaccines in the future," Dr. Matthew Memoli, Laboratory of Infectious Diseases, National Institutes of Health (NIH), explained.
Researchers are hoping to conduct the study on up to 100 people during the next year.