Fever-Reducing Medications May Spread the Flu

Flu fever reduction could increase influenza cases and deaths

(RxWiki News) When people start to run a fever from the flu, they often turn to medications like ibuprofen to bring the fever down. But it seems this common strategy might be dangerous.

Canadian researchers have concluded that fever-reducing medications may actually help to spread the flu and even lead to more flu deaths.

Why is this? Because fever is an immune response that fights the flu virus. Medicines that reduce the fever can stop this process so that folks may still be infectious and able to pass along the virus to others.

"Make sure you’re completely clear of the flu before returning to work."

To conduct this study, David Earn, PhD, an investigator with the Michael G. DeGroote Institute for Infectious Disease Research (IIDR) and professor of mathematics at McMaster University, collaborated with colleagues at the university, Paul W. Andrews, PhD, and Benjamin M. Bolker, PhD.

Fever reducing medications include aspirin or acetylsalicylic acid (found in Alka-Seltzer, Anacin, Bayer, Ecotrin, Excedrin and others), ibuprofen (brand names Advil, Motrin and others), and acetaminophen (Tylenol and others). Aspirin-containing products should never be given to children under the age of 18 with flu-like symptoms due to an increased risk of a potentially fatal childhood disease called Reye’s Syndrome.

"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,” Dr. Earn said in a statement.

Dr. Earn and team identified research data from both human and animal studies to enter into a mathematical model to estimate how much virus could be transmitted from an individual who had used fever-reducing medication. The model then calculated the increase in the number of flu cases in one year, as well as during a flu pandemic.

The investigators, who admitted the data was incomplete, estimated that fever suppression increases the expected number of flu cases and deaths by 5 percent in the US. This translates to more than 1,000 additional deaths in a typical year in North America, according to the authors.

The research team calculated that in a pandemic, fever reduction medications could result in a 1 percent increase in cases.

David Price, professor and chair of family medicine for McMaster's Michael G. DeGroote School of Medicine, said, "As always, Mother Nature knows best. Fever is a defense mechanism to protect ourselves and others. Fever-reducing medication should only be taken to take the edge off the discomfort, not to allow people to go out into the community when they should still stay home."

The authors of this study acknowledged that their findings are what they call “best available estimates,” but do not equate to concrete recommendations.

“We hope that our analysis in this paper will spur further research to determine more precise estimates of the effects that we have discussed,” the researchers concluded. “Such estimates should assist in the development of evidence-based guidelines for antipyretic [fever reduction] treatment practices.”

This study was published January 21 in the Proceedings of the Royal Society B.

The study was supported by the Natural Sciences and Engineering Research Council of Canada and the Michael G. DeGroote Institute for Infectious Disease Research.

Review Date: 
January 21, 2014