Available online 23 May 2024

Author links open overlay panel, Abstract

Fever has roles both in host defense against infectious challenges and in guidance of medical intervention. These roles remain insufficiently acknowledged and considered by both health care providers and patients and their families. This review cites reports in support of both roles and provides recommendations regarding the clinician's approach to fever, as well as points relevant for education of patients and their families.

Section snippetsHistorical Concepts of Fever and Persisting Fever Phobia in Recent Times

From the time of Hippocrates to the time of Wunderlich in the late 1800s, fever was considered a natural response to challenge, a key element of the human host's physiology1,2. In fact, “fever therapy,” consisting of killed pathogenic bacteria in pill form, was a component of the American military's medical bag in the 1800s, and the use of fever therapy to treat neurosyphilis resulted in a Nobel prize in 19272. However, in the 1870s and following years, antipyretics such as salicylic acid were

Potential Role of Fever for the Challenged Host

It is important to recognize the survival benefit of fever during pathogen challenge for the species and, very likely, for the human individual, even if difficult to establish for the latter. Different classes of microorganisms have varying optimal viable temperature ranges2. Fever could conceptually benefit the host by having an adverse effect on the challenging pathogen by thermal restriction for some pathogens8, by enhancing the actions or effects of natural biological factors9 or

Recognition of Fever

It is also important to recognize another supportive role of the febrile response during challenge by a pathogen, specifically its value regarding decisions about medical intervention.

The definition of a normal human temperature provides a baseline for recognizing a fever. It is now quite clear that a range of temperatures is normal for healthy individuals33. Additional recent reports have re-examined the range of normal human body temperature and have indicated both a lower mean and a lower

Why Suppress Fever?

One postulated reason to treat fever is that it has reached a harmful level. However, a febrile rise in temperature rarely exceeds 41°C in humans38 and such rises are generally considered harmless for most individuals. Patients usually do not experience discomfort due to fever per se below 39.5-40°C and 41-42°C can be tolerated by most individuals without heat stroke. Temperatures greater than 42°C are usually harmful. Certain populations have been cited as potentially affected adversely by

Conclusions

Accumulated direct and indirect evidence suggests an overall beneficial effect of fever on host defense mechanisms, and extensive clinical practice observations suggest that analysis and action based on the febrile response can contribute significantly to the most appropriate application of medical interventions. Common sense also argues for a beneficial role of fever, to assure its place over time and across species, as an evolutionary response to infection. Currently many but not all

Financial Support

The authors received no financial support for this work.

Declaration of competing interest

The authors state that they have no conflicts of interest.

Acknowledgments

Author contributions. N.J.R. and J.C.S conceived and wrote the manuscript.

Funding. The authors received no funding for this work.

Conflicts of interest. The authors report no conflicts of interest.

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© 2024 Published by Elsevier Inc. on behalf of Southern Society for Clinical Investigation.