Associate Professor Deborah Friedman
School of Medicine, Deakin University.
Winter can be cold and miserable, especially when you’re stuck in bed with a runny nose and a fever. Then spring comes along, filling the air with warmth, optimism – and viruses.
For most of us, it’s largely unavoidable that we’ll get struck down by a cold at some point during the year. ‘The average person will experience several bouts of the common cold per year, causing absences from school and work,’ says Associate Professor Deborah Friedman from Deakin’s School of Medicine. ‘The average incidence of the common cold is five to seven episodes per year in preschool children, and two to three per year in adulthood.’
Hand-to-hand contact, such as shaking hands with people, is almost a guaranteed way to spread germs. Other ways to catch a cold include through respiratory droplets expelled by coughing and sneezing, and via contaminated environmental surfaces like door handles, tables and shared computers and tools.
‘The risk of person-to-person transmission is usually dependent on the amount of time people spend together, the proximity of their contact with one another, and the amount of virus shed by the infected patient,’ Assoc. Prof. Friedman says.
Although technically what we call the ‘common cold’ is more of ‘an illness syndrome caused by approximately 200 different viruses’, it’s ‘the most common illness affecting people in the developed world’, says Assoc. Prof. Friedman. So what can you do to lower your chances of catching it?
‘Hand hygiene is probably the single most effective strategy to prevent the common cold,’ Assoc. Prof. Friedman asserts. ‘Hand-to-hand transmission is the most common mechanism of spread of the common cold, and some cold-causing viruses may remain viable on the skin for up to two hours.’
She recommends keeping your hands clean with water and soap (either liquids or bars) or alcohol-based hand rub products. But before you get too over-confident, ‘be aware that the method for effectively washing hands with soap and water is a time-consuming, multi-step process,’ she adds. You need to rub your hands together with soap vigorously for at least 20 seconds to make sure they’re free of nasty viruses.
We all know it’s ideal to aim for somewhere around eight hours of consistent sleep every night. Aside from putting yourself at higher risk of getting sick, there are plenty of downsides to not getting a good night’s sleep.
Assoc. Prof. Friedman cites the results of one study that inoculated brave (or crazy) participants with rhinovirus via nasal drops in a controlled environment that showed a connection between sleeping less and being more susceptible to catching a virus.
‘It found that those who slept five or fewer hours per night were almost three times more likely to develop the common cold than those who slept more than seven hours per night,’ she says.
There’s been a lot of talk of the health benefits of probiotics recently – whether you get them through pills, probiotic drinks or simply eating foods rich in probiotics (such as yoghurt, sauerkraut, miso soup or pickles).
Although Assoc. Prof. Friedman says ‘it remains uncertain whether probiotics have a role in the prevention of respiratory tract infections in adults,’ some studies have suggested they may help.
‘A meta-analysis of 12 randomised trials found that probiotics reduced the number of individuals experiencing at least one episode of acute respiratory tract infection. These trials included both children and adults and compared placebo with probiotics (strains of lactobacilli and Bifidobacterium),’ she says.
But don’t bank on your lunchtime pickle sandwich warding off all coughs and sneezes. ‘Better quality trials are needed to confirm these findings’, Assoc. Prof. Friedman points out.
If you’re one of the many people who stock up on vitamins hoping they’ll help prevent the common cold, Assoc. Prof. Friedman has bad news for you. ‘Unfortunately, no vitamins (including vitamins C, D and E) or herbal products (including garlic, ginseng and gargling with betadine) have been shown conclusively to impact the incidence of the common cold.’
Vitamin supplements are generally only recommended if your diet is lacking in certain nutrients.
One scientific study did link vitamin C with a decrease in colds – but only in people exposed to vigorous activity, especially in extreme conditions – such as marathon runners, skiers and soldiers in sub-arctic conditions. These participants saw a 50% decrease in the development of colds when taking regular vitamin C.
‘It is unknown whether the physical activity, the vitamin C supplementation or their combination caused the observed effect,’ Assoc. Prof. Friedman adds.
As opposed to vitamins mentioned above, zinc is a mineral that has also been studied as a common cold preventer to some success, in lozenge, liquid and tablet form.
‘A systematic review of two randomized trials in children found that zinc sulfate taken for a minimum of five months decreased the rate of development of colds and school absence,’ Assoc. Prof Friedman explains. ‘These findings may however not be applicable to adults, who develop colds less frequently.’
Plus, before you go out and stock up on zinc supplements, consider that you’d need to take them for many months and the side effects may outweigh the potential benefits. ‘Zinc lozenges do result in nausea and a bad taste in the mouth,’ Assoc. Prof. Friedman says.
‘In conclusion, while an ounce of prevention is supposed to be preferred to a pound of cure, aside from the proven benefits of hand hygiene and more sleep, it is unclear how heavily to weight the benefit of the multitude of other available strategies and preparations for prevention of the common cold,’ Assoc. Prof. Friedman concludes.
Still sneezing after all this? Maybe it’s hayfever. Find out why Melbourne is the world’s allergy capital.
School of Medicine, Deakin University.
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