Why do people catch colds and flu more often in the winter? Are viruses transmitted more easily in damp air, is the resistance of the population reduced by the cold and lack of sunlight, or do the viruses simply take advantage of the greater time we spend indoors with each other?
A: There is no one reason why we get more colds and flu in winter. The rhinovirus, which is responsible for up to 40 per cent of colds, cuitures better at a temperature of 32 °C rather than the normal body temperature of 37 °C. However, 32 °C is the normal temperature of the lining of the nose, which is good news for the virus.
We do tend to be indoors more often in poorly ventilated areas during the winter and this aids the airborne transmission of viruses. Similarly, ultraviolet will kill viruses and this may be another factor as there is obviously much less sunlight in winter.
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However, I believe that one of the biggest factors for the great increase in colds that occurs in early autumn and just after Christmas is the return of schoolchildren and students to schools and colleges.
Children and teenagers are far more susceptible to infection as their immune system learns how to combat more infections as they get older and have been exposed to more of the 200 or so viruses responsible for the common cold. Densely packed nurseries, schools and colleges provide an ideal breeding ground for viruses which then spread out into the community, aided by the colder damp weather.
This week’s questions Can any schoolteacher save the reputation of their profession and provide the answers to the two questions below?
Shedding light: During a physics A level practical lesson my tutor placed a lit candle on a turntable. When the table revolved we expected to see the flame on the candle point outwards but, instead, it pointed inwards. The school head of science couldn’t explain this. Can anyone else?
Resonant request Why are metals sonorous- Our physics and chemistry A level teacher does not know and no reason is given in any of the textbooks we can find.
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