HPA advice on antipyretics does not contradict NICEBMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b3501 (Published 01 September 2009) Cite this as: BMJ 2009;339:b3501
All rapid responses
Antipyretic treatment of flu
It is astonishing that in the 21st century we are debating the use of
paracetamol to reduce the body temperature and alleviate the symptoms of
flu..1 There are powerful science based a priori reasons for regarding
this advice as potentially counter- productive..
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 and 35º C, so inhaling air at about 45º C
for twenty minutes will significantly improve the symptoms of a common
cold.2 Conversely, treating the common cold with aspirin causes a
significant increase in the rate of production of the virus.3
On the other hand, the influenza viruses, which infect the whole
body, grow best at temperatures only slightly below body temperature and
at 40º 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
Although there appear to be no studies of the effect of lowering or
raising body temperatures in humans suffering from flu, there are
obviously good reasons for treating flu by encouraging the temperature to
rise to 40º C and maintaining this for at least 24 hours.
The absence of such trials may be due to a deep-seated fever-phobia
stemming from pre-scientific 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”. Both the public and the medical profession have still not realised
the full significance and potential of this statement.
1 McCracken J. HPA advice on antipyretics. BMJ 2009; 339:530 (5
2 Tyrell D, Barrow I, Arthur J. Local hyperthermia benefits natural
and experimental common colds. BMJ 1989;298:1280-3.
3. Stanley ED, Jackson GG, Panusarn C, Rubenis M, Dirda V.
Increased virus shedding with aspirin treatment of rhinovirus infection.
4. 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.
Competing interests: No competing interests