It sounds counterintuitive, but taking medicines that lower fever could actually have the potential to spread the flu.
That's because when people take these medicines, they feel well enough to go to work or school. But that doesn't mean they aren't still sick -- or contagious.
And "because fever can actually help lower the amount of virus in a sick person's body and reduce the chance of transmitting disease to others, taking drugs that reduce fever can increase transmission," study researcher and mathematics professor David Earn, of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University, said in a statement.
For the study, published in the journal Proceedings of the Royal Society B, Earn and his colleagues examined data from different studies, including some done on humans and some on ferrets, to calculate how much more virus a person would give off if he or she took fever-reducing medication. They used mathematical modeling to calculate how this would affect overall flu cases in a year.
The researchers found that suppressing fever would lead to annual flu cases going up by about 5 percent -- or an additional 1,000 flu deaths in North America.
The study is based on mathematical modeling, and not on actual numbers of people who have been infected with flu because others took anti-fever medication. With all the hypotheticals, the "paper is of interest, but more in terms of theory than practice," Arnold Monto, an expert in infectious disease epidemiology at the University of Michigan, who was not involved in the study, told USA Today.
Indeed, Earn told NBC News that "we aren't saying don't take medication. That's not the message." Instead, he urged that people should "be aware that if you take this medication, there is this effective increase in transmission."