COLD AND COLDS 



Sir Christopher Andrewes 



Overchalke Coombe Bissett 

 Salisbury, England 



ABSTHACT 



Two problems arise: (1) Does cold really precipitate colds in individuals? (2) Why 

 are colds commoner in summer? Are these two problems or only one problem? (1) 

 The popular belief that cold or damp can precipitate a cold is very strong. Experi- 

 ments at the Salisbury Common Cold Unit failed to confirm the notion. Can the belief 

 be due to popular confusionbetween cause (fall in temperature) and the earliest symptom 

 (a feeling of chilliness); or does this effect of cold only act in certain infrequent in- 

 dividuals or at certain infrequent moments, when virus in a latent state can be acti- 

 vated? Chilling does not seem to activate colds in small isolated communities in the 

 Arctic or elsewhere. (2) Colds are certainly commoner in temperate zones in winter 

 than in summer. Many observers report three waves - one in September- October, 

 one in January, and often a third, lesser one in March. Very many things can be cor- 

 related with change in season; but which are the important ones? There is little evi- 

 dence that temperature is itself the direct cause. Rather better, but still unconvincing, 

 evidence might implicate humidity, perhaps because cold viruses could survive better 

 in the air at low relative humidities. A "winter factor" could operate in such a way, 

 favouring the virus' survival, or indirectly through change in people's habits, again 

 permitting more cross- infections to occur. There may be "conditioned epidemics", 

 a vinis such as Influenza being seeded into a population but not manifesting itself un- 

 til conditions, perhaps meteorological ones, are favourable. Possibly the physiology 

 of the respiratory mucosa is all important. A homoeostatic mechanism may not re- 

 spond promptly enough to environmental changes and virus attack may be favoured 

 at this "unguarded hour". Recent work at Salisbury and elsewhere, permitting identi- 

 fication and titration of "Rhinovi ruses" offers hope of a direct attack on some of 

 these questions. Understanding of the natural history of colds may offer better hope 

 of controlling such infections than a programme directed towards specific viruses. 



I have not come all the way to Alaska to tell you what the relation 

 between cold and colds is; rather, I have come in hope that in the 

 discussion following my remarks some light may be shed on the 

 obscurity which veils this subject. Why are colds called "colds"? 

 Is it because the subject feels cold, or is it because chilling is 

 thought to precipitate an attack? Or perhaps because colds come at 

 the cold season of the year ? We have really to consider two prob- 



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