Why Fever is Crucial

A few years ago, on completing an intense months-long pharmacology course, I was shocked to learn that keeping a baby’s fever down with ibuprofen (Advil) or acetaminophen (Tylenol) will NOT prevent febrile seizures. While parents are now more widely aware of this myth, patients and practitioners still seem generally unaware of the possibility that blocking a low-grade fever could be harmful.

Fever is Essential

Fever is our body’s natural defense mechanism against infection – it’s not an illness. Up to possibly 40°C, an efficient fever response to an infection stimulates immune cells and the immune system, directly inhibits replication of many pathogens (disease-causing microbes), revs up our metabolism to clean-up the mess, and promotes recovery. We even have little proteins called “heat-shock proteins” that protect us from some of the damage intended for the pathogen. (It’s important to know that fevers over 40°C, fevers that run longer than 48 hours, or those due to non-infectious causes, such as in heatstroke, allergies, or various drug side-effects, are possibly harmful and require medical attention.)

Fever is a conserved evolutionary response to infection and the idea of stoking a healthy fever dates back thousands of years in the East. In the West however, this understanding appears to date back only to experiments in the 1980s, in which infected iguanas survived only if they were allowed or able to mount a fever.¹ This was followed by a variety of animal studies also suggesting harm from fever suppression and at least one human population study published in 2014.^2-3 In 2015, research in which clinicians inhibited fever above 38.5 degrees in critically ill patients was terminated because of a higher number of deaths compared to patients whose fever was allowed to climb to 40 degrees, and other papers identified a 5% increased risk of death in patients with influenza if the fever was suppressed with medication.^4-5 As for the coronavirus, correspondence published in the Lancet Respirology only hints at possible harm from ibuprofen and officials in France are warning (via public media channels) that medications such as ibuprofen might increase complications of infection.^6-7

Some Fever Guidelines:

1. Normal body temperature varies alongside our circadian rhythm. A normal temperature of about 37°C (98.6°F) fluctuates naturally by 0.5 to 1 degree. It is often highest in the evening and in the middle of a woman’s menstrual cycle (ovulation). Monitor for fevers in the evening especially. (Many old-world medicines promote encouraging a fever early in the night with botanicals and breaking a fever as the night progresses. Working with a knowledgeable healthcare provider here is highly recommended though.)

2. A rectal temperature in children younger than 5 is most accurate, and necessary for accuracy in children younger than 2 years. A fever consistently higher than 38 degrees when measured this way, indicates a fever.

3. The intensity of a fever says just as much about the person as it does about the infection. An intense fever can occur in the presence of a weak infection and a weak fever can signal an aggressive infection. Look at the person’s behaviour and level of awareness as better clues. A stiff neck can also be a big red flag. If there’s any doubt at all, seek medical attention (especially for children and for fevers lasting more than 48 hours).

4. Many pathogens thrive in a dry environment. Ensure that patients with a fever are well hydrated(water, broth, and herbal teas – no sugar), and that acute constipation is addressed quickly as a means of supporting a person’s recovery.

5. If the patient is strong enough, respect the person’s appetite and avoid eating during a new fever. The evidence isn’t clear, but old world approaches support short-term fasting as a way to help break a fever.

Resources:

Patient education: Fever in children (Beyond the Basics)

References:

1. Blomqvist A, D Engblom. Neural Mechanisms of Inflammation-Induced Fever. Neuroscientist. 2018 Aug;24(4):381-399. doi: 10.1177/1073858418760481.
2. Eyers S, Weatherall M, Shirtcliffe P et al. The effect on mortality of antipyretics in the treatment of influenza infection: systemic review and meta-analysis. J R Soc Med. 2010 Oct;103(10):403-411. doi: 10.1258/jrsm.2010.090441.
3. Earn D, Andrews P, Bolker B. Population-level effects of suppressing fever. 2014 Mar;281(1778). https://doi.org/10.1098/rspb.2013.2570.
4. Walter E, Hanna-Jumma S, Carraretto M, Forni L. The pathophysiological basis and consequences of fever. Crit Care. 2016;20:200. doi: 1186/s13054-016-1375-5.
5. Evans SS, Repasky EA, Fisher DT. Fever and the thermal regulation of immunity: the immune system feels the heat. Nat Rev Immunol. 2015;15(6):335-349. doi:10.1038/nri3843
6. Fang L, Karakiulakis G, Roth M. Are patients with hypertension and diabetes mellitus at increased risk for COVID-19 infection? Lancet Respir Med. 2020 Published Online March 11, 2020 https://doi.org/10.1016/PII.
7. Anti-inflammatories may aggravate Covid-19, France advises. Sat 14 Mar 2020.