It’s not just humans that spike fevers when they’re sick. Fish, reptiles, and other mammals—like rabbits and dogs—get fevers as well.
When I was about 12 years old, my father’s best friend told me that medical science hadn’t found any reason that humans get fevers. My dad’s friend, Rick Sullivan, M.D., was an emergency room doctor based in Cambridge, Massachusetts. He said the medical profession believed that the dangers of having a fever outweighed any theoretical benefits.
Even then I was skeptical. It felt counterintuitive to me that fever served no evolutionary purpose, and that we humans should use artificial means to reduce fever when we get sick.
But in 2015 three scientists at the Roswell Park Cancer Institute published an article in Nature Reviews Immunology that showed that fever stimulates the immune system to help the body mount an effective response against infection and disease.
“The fever response … confers a survival benefit during infection,” the authors wrote.
Other research also suggests this is true. While most of these studies are small, scientists have found that children with sepsis are more likely to die if their fevers are lowered; that using fever reducers can prolong chickenpox, as well as symptoms associated with the flu, and with the common cold.
Some fascinating research done by a large team of scientists in China and published in 2019 gives a possible explanation for the biochemical mechanism underlying the benefits of getting a fever. This team found that the heat from fever boosts two molecules that help certain white blood cells (T cells) get from blood vessels into the lymph nodes.
According to the scientists, these molecules, alpha-4 integrin and heat shock protein 90, serve an important function: When they get into the lymph nodes they team up with other immune cells to more effectively attack infectious germs.
So, it seems that spiking a fever helps your body fight disease and the fever itself, the heat, is beneficial.
Protective Against Cancer?
Not only that, but having a fever might actually be protective against cancer.
“Retrospective as well as prospective clinical studies indicate that episodes of high fever as a typical reaction to an acute infection during the entire human life span are inversely related to cancer incidence,” argued a team of scientists from the Department of Immunology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Poland in 2015.
Finally, I believe that fever serves another important function. When you have a fever, you don’t want to be around other people. You want to be in bed, asleep or resting, because you feel so badly and have so little energy. This self-isolation helps you heal. And it also helps other people around you not get sick.
Antipyretics Aren’t Safe
At the same time, there are safety issues with over-the-counter fever reducers themselves. I’m especially concerned about acetaminophen, the main ingredient in Tylenol.
Though conventional doctors will tell you it is “safe” to give baby Tylenol to an infant or small child, there’s no nice way to say this, they are simply wrong. Tylenol is not only harmful to a baby’s liver, it is likely a causative factor in the sharp rise in autism, according to scientists from Duke and Harvard universities.
NSAIDs (non-steroidal anti-inflammatory drugs), like Motrin, aren’t a good alternative either.
That doctor that told you to alternative between Tylenol and Motrin should also tell you that the NSAIDs can wreck havoc on a baby or a grown-up’s belly, causing leaky gut syndrome and even stomach ulcers, especially when taken for more than a day or two.
Sure, taking them from time to time or giving one or two doses to your baby likely won’t hurt. But NSAIDs are cytotoxic, which means they harm our cells. And the cells that line our intestines are especially vulnerable.
But, wait, there’s more: The regular use of NSAIDs have also been found to cause endocrine disruption in women, which can lead to fertility issues. And if you follow the health news or you’re trying to conceive, you already know that a growing number of young adults who are desperate to have children are dealing with infertility.
What If You Have a Fever? (Or Your Baby Does?)
Instead of fearing fever, celebrate it. Know that the fever is an indication that your immune system is coming on-line to fight an infection.
Dr. Paul Offit, Director of the Vaccine Education Center and professor of pediatrics in the Division of Infectious Diseases at Children's Hospital of Philadelphia, and I don’t agree on much. But we do agree on this:
Let the fever burn.
And while you’re burning up with that beneficial fever, listen to your body. Don’t be all Type A and try to get stuff done. Rest. Sleep. Stay in bed. Stay off your phone.
That’s likely what your body is telling you to do. By resting you give yourself a chance to heal.
At the same time, make sure to stay hydrated. Drink filtered water, take sips of freshly pressed vegetable juices, enjoy your mom’s chicken soup or some bone or vegetable broth.
You may also find taking an epsom salt bath or putting a wet washcloth on your forehead can be very healing when you have a fever.
You feel miserable now, but you’ll be better in no time. Especially if you let it burn.
Alternatives to Tylenol: Better, Safer Remedies
No, Tylenol’s Not Safe During Pregnancy, Here’s Why
What Doesn’t Kill You Makes You Stronger
Thank you for your article! It is sad that it took until 2015 for anyone to look into it; fever working to stimulate the immune system is not news. How to Raise a Healthy Child in Spite of Your Doctor, a book written in 1987 by Dr Robert Mendelsohn, MD was where I first heard about the benefit of a fever. In it, he shared that they were taught in medical school that fevers are beneficial.
In my German culture, my mother would bring out the fat fluffy featherbeds and tuck us under them to break the fever. (i.e. raise the body temperature) The room would get darkened and we would get served hot mint tea with honey. And of course sleep was part of the healing. I never got fever reducing drugs.