//Fevers, good or bad

Fevers, good or bad

Fever, good or bad?

Normal body temperature, 36 – 37oC (96.8 – 98.6oF)

Fever reduces illness severity and length

Sharon S. Evans, Professor of Oncology and Immunology, N.Y.

Fever acts to mobilize multiple arms on the immune system, a function that is remarkably well conserved across many, many species — both warm-blooded and coldblooded

Fever affects every aspect of the immune system to make it work better

Fever and the thermal regulation of immunity: the immune system feels the heat


Conserved in warm and cold-blooded vertebrates

Desert iguana, blue-finned tuna and leech, antipyretic drugs

Common biochemical pathways

Integrated physiological and neuronal circuitry

Confers a survival benefit during infection

Fever stimulates innate and adaptive immune responses

May reduce inflammation

Pyrogenic cytokines interleukin-6 (IL-6)

Mounting evidence that the increase of 1 to 4°C in core body temperature …

is associated with improved survival and resolution of many infections

Use of antipyretic drugs, correlates with a 5% increase in mortality, in influenza

Negatively affects patient outcomes in the intensive care unit

Uncontrolled fever is associated with worse outcomes in sepsis or neurological injuries

Dr. Paul Offit, Vaccinologist, University of Pennsylvania

Treating fever can prolong or worsen illness

Fever enhances survival

That accounts for its persistence throughout animal evolution,
even though it exacts a significant metabolic cost.

A 1°C rise in body temperature requires a 10–12.5% increase in metabolic rate

Immunity, both innate and adaptive, works better at higher temperatures