(Please note that this letter was written before a Canadian study published in 2014 provided evidence that “fever suppression increases the expected number of influenza cases and deaths in the US”.
Fever may be used as treatment
BMJ 2004;329:1238.2
EDITOR—Because there is no specific treatment for influenza, Jefferson’s editorial and the accompanying articles concentrate on vaccination and chemoprophylaxis.1 However, I plead for recognition that fever may be used as a non-specific treatment of flu. The fever is not just an unpleasant symptom of flu but a crucial part of the body’s defence mechanism that should be encouraged.
Infectious organisms are adapted to the temperature of the part of the body they colonise, so it follows that they will grow best at that temperature. Rhinoviruses, which infect the cooler upper airway and sinuses, grow best between 33° C and 35° C, so inhaling air at about 45° C for 20 minutes will much improve the symptoms of a common cold.2 Conversely, treating the common cold with aspirin causes an increase in the rate of production of the virus.3
By contrast, influenza viruses, which infect the whole body, grow best at temperatures slightly below body temperature, and at 40° C they will die off after 12-24 hours. So it is not surprising that if fever is suppressed in ferrets infected with the flu virus, their illness is prolonged.4
There seem to be no studies of the effect of lowering or raising body temperatures in humans with flu. But there are obviously good reasons for trials of treating flu by raising the temperature to 40° C and maintaining this for at least 24 hours. The absence of such trials may result from a deep seated fever phobia, stemming from prescientific medicine when fever was perceived as an illness in itself. A famous 17th century physician, Thomas Sydenham, said, “Fever is nature’s engine which she brings into the field to remove her enemy.”5 The public and the medical profession have still not realised the full importance and potential of this statement.
Alan W Fowler, retired consultant orthopaedic surgeon
Bridgend CF31 1QJ alan@awfowler.fsnet.co.uk
Competing interests: None declared.
References
- Jefferson J. How to deal with influenza? BMJ 2004:329: 633. (18 September.)[Free Full Text]
- Tyrell D, Barrow I, Arthur J. Local hyperthermia benefits natural and experimental common colds. BMJ 1989;298: 1280-3.[ISI][Medline]
- Stanley ED, Jackson GG, Panusarn C, Rubenis M, Dirda V. Increased virus shedding with aspirin treatment of rhinovirus infection. JAMA 1975;231: 1248-51.[Abstract]
- Husseini RH, Sweet C, Collie MH, Smith H. Elevation of nasal virus levels by suppression of fever in ferrets infected with influenza viruses of differing virulence. J Infect Dis 1982;145: 520-4.[ISI][Medline]
- Payne JF. Thomas Sydenham. London: T Fisher Unwin, 1900.
