Fever-reducing medications may aid spread of influenza, study finds

January 21, 2014

Contrary to popular belief, fever-reducing medication may inadvertently cause more harm than good.

New research from McMaster University has discovered that the widespread use of medications that contain -reducing drugs may lead to tens of thousands more influenza cases, and more than a thousand deaths attributable to influenza, each year across North America. These drugs include ibuprofen, acetaminophen and acetylsalicylic acid.

"When they have flu, people often take medication that reduces their fever. No-one likes to feel miserable, but it turns out that our comfort might be at the cost of infecting others," said lead author David Earn, an investigator with the Michael G. DeGroote Institute for Infectious Disease Research (IIDR) and professor of mathematics at McMaster University.

"Because fever can actually help lower the amount of virus in a 's body and reduce the chance of transmitting disease to others, taking drugs that reduce fever can increase transmission. We've discovered that this increase has significant effects when we scale up to the level of the whole population."

The study, published in the Proceedings of the Royal Society B today, was co-authored with McMaster professors Ben Bolker, of the departments of mathematics & statistics and biology and the IIDR, and Paul Andrews of the Department of Psychology, Neuroscience and Behaviour.

"People often take—or give their kids—fever-reducing drugs so they can go to work or school," Earn said. "They may think the risk of infecting others is lower because the fever is lower. In fact, the opposite may be true: the ill people may give off more virus because fever has been reduced."

The researchers assembled information from many sources, including experiments on human volunteers and on ferrets (which are the best animal model for human influenza). They then used a mathematical model to compute how the increase in the amount of virus given off by a single person taking fever-reducing drugs would increase the overall number of cases in a typical year, or in a year when a new strain of influenza caused a flu pandemic.

The bottom line is that fever suppression increases the number of annual cases by approximately five per cent, corresponding to more than 1,000 additional deaths from influenza in a typical year across North America.

"This research is important because it will help us understand how better to curb the spread of ," said David Price, professor and chair of family medicine for McMaster's Michael G. DeGroote School of Medicine.

The family physician agrees with the researchers' conclusions. "As always, Mother Nature knows best. Fever is a defence 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."

"People are often advised to take fever-reducing drugs and texts state that doing so is harmless," added Andrews. "This view needs to change."

The research findings echo previous research that has shown how the widespread use of medication can have unwanted effects on the transmission of disease. For example, it is now well accepted that the indiscriminate use of antibiotics has driven the emergence of life-threatening antibiotic resistant bacteria.

Bolker said: "Parents and health care professionals alike have focused on making their children or patients feel better by reducing fever, without being aware of potentially harmful side effects at the population level.

"Although we have put together the best available estimates for each parameter in our model, we have a long way to go before we can make concrete policy proposals.

"We need more experiments to determine precisely how much reducing fever increases viral shedding in humans, and to estimate how much more people spread disease because they are more active in the community when they alleviate their symptoms by taking medication."

Explore further: WHO says single yellow fever shot is enough

More information: Population-level effects of suppressing fever, rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2013.2570

Related Stories

Weather patterns play significant role in seasonal influenza

September 11, 2013

Influenza is like a cloud, moving across Canada with the fall weather. McMaster researchers have established that the spread of seasonal flu in Canada is tied to low temperature and low humidity, and travels west to east—findings ...

Valley fever hospitalizations increase in Calif.

September 11, 2013

A new study published by the Centers for Disease Control and Prevention shows the annual rate of hospitalizations for valley fever, a potentially lethal but often misdiagnosed disease, has doubled over the past 12 years in ...

Shanghai reports two deaths in China bird flu outbreak

January 20, 2014

Two people have died from the H7N9 strain of bird flu in China's commercial hub Shanghai, including a medical doctor, the local government said Monday, the city's first fatalities from the virus this year.

Recommended for you

Monkeys in Asia harbor virus from humans, other species

November 19, 2015

When it comes to spreading viruses, bats are thought to be among the worst. Now a new study of nearly 900 nonhuman primates in Bangladesh and Cambodia shows that macaques harbor more diverse astroviruses, which can cause ...

One-step test for hepatitis C virus infection developed

November 14, 2015

UC Irvine Health researchers have developed a cost-effective one-step test that screens, detects and confirms hepatitis C virus (HCV) infections. Dr. Ke-Qin Hu, director of hepatology services, will present findings at the ...

Computer model reveals deadly route of Ebola outbreak

November 10, 2015

Using a novel statistical model, a research team led by Columbia University's Mailman School of Public Health mapped the spread of the 2014-2015 Ebola outbreak in Sierra Leone, providing the most detailed picture to date ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Jan 21, 2014
This is not just "a possibility". Its plain common sense. The body produces a fever for the purpose of killing germs. And going to work/school when sick is irresponsible. Not that I havent been guilty of it, but thats just the truth.
not rated yet Jan 21, 2014
Does the same concern apply if you have had the annual flu' vaccination ??

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.