Health Check: how long should you stay away when you have a cold or the flu?



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Symptoms of the flu generally develop more quickly and are more severe than the common cold.
By txking/Shutterstock

Nadia Charania, Auckland University of Technology

Most adults get around two to three colds a year, and children get even more. In terms of the flu, there are around 3-5 million severe cases of influenza worldwide each year and 290,000 to 650,000 deaths.

The symptoms of a cold and the flu are similar, so it’s hard to tell the difference. But the flu is usually more severe and develops more quickly than a cold.

Colds and flus can be easily passed from person to person through the air, when an infected person coughs or sneezes, and touch, when a person touches an infected surface or object like doorknobs and light switches.

So what’s the difference between colds and flus, and how long should you stay away?

Colds

Cold symptoms include a sore throat, cough, runny or stuffy nose, tiredness and headache.

Most people become contagious with cold symptoms one to two days after exposure to a cold virus. These symptoms usually peak two to four days later. The common cold usually lasts about ten days.




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There is nothing you can take to shorten the duration of a cold, and most people will get better without needing to see a doctor. But some over-the-counter medications can help alleviate the symptoms. These include anti-inflammatories (to reduce inflammation or swelling), analgesics (to reduce pain), antipyretics (to reduce fever) and decongestants (to relieve nasal congestion).

But be careful you follow the instructions and recommended dosage for these medications. A recent study of US adults who used paracetamol, the active ingredient in many cold and flu medicines, found 6.3% of users exceeded the maximum recommended daily dose. This mostly occurred during the cold and flu season.

For your own and others’ health, the best place for you to be when you’re sick is at home.
Shutterstock

Natural products such as vitamin C and echinacea are sometimes recommended to prevent and treat a cold, but there is limited evidence to support their effectiveness.

The flu

Common symptoms of the flu include fever (a temperature of 38°C or higher), cough, chills, sore throat, headache, runny or stuffy nose, tiredness and muscle aches.

An infected person can spread the flu for five to seven days after becoming infected. The infectious period can begin 24 hours before the onset of symptoms. This means you can spread the flu without even knowing you’re sick.

Influenza viruses can cause mild to severe illness in people of all ages. Most people will fully recover within one to two weeks and won’t require any medical attention. Similar to a cold, people can take some over-the-counter medications and other remedies to help alleviate symptoms.




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But some people can become acutely unwell with the flu. They may require antiviral medication and, in severe cases, hospitalisation. Those at high risk include pregnant women, children, the elderly, and people with certain medical conditions such as HIV/AIDS, asthma, diabetes and heart and lung diseases.

The flu virus strains that circulate usually change every year, so the best way to prevent getting the flu is to get the annual flu vaccine. The vaccine is moderately effective and recommended for adults and children over the age of six months. Some common side effects may occur, such as temporary soreness, redness and swelling at the injection site, fever, headache, muscle aches and nausea.

Wash with soap for at least 20 seconds to kill the germs.
Shutterstock/Alexander Raths

Avoid passing it on

If you feel unwell, stay home from work or school and rest (and get plenty of fluids) until you feel better. If you’ve had a fever, stay home for at least 24 hours after the fever has broken.

When you go back to work or school, you may still be infectious, so avoid passing the virus on by:

  • regularly washing your hands with soap and water for at least 20 seconds and drying them properly – if soap and water are not available, use an alcohol-based hand sanitiser

  • practising good cough and sneeze etiquette: cover your mouth and nose with a tissue or your upper shirtsleeve when you cough or sneeze, and throw away used tissues immediately

  • not touching your eyes, nose and mouth

  • The Conversationfrequently cleaning the surfaces and objects you’ve touched.

Nadia Charania, Senior Lecturer, Public Health, Auckland University of Technology

This article was originally published on The Conversation. Read the original article.

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Health Check: should I take vitamin C or other supplements for my cold?



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Once you have a cold, taking vitamin C supplements won’t do anything.
From shutterstock.com

Clare Collins, University of Newcastle

Last week I had a shocking cold. Blocked nose, sore throat, and feeling poorly. This made me think about the countless vitamins and supplements on the market that promise to ease symptoms of a cold, help you recover faster, and reduce your chance of getting another cold.

When it comes to the common cold (also called upper respiratory tract infections) there is no magic cure (I wish) but some supplements may deliver very minor improvements. Here is what the latest research evidence says.




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Vitamin C

For the average person, taking vitamin C does not reduce the number of colds you get, or the severity of your cold.

In terms of how long your cold lasts, some studies have looked at people taking vitamin C every day, while others have focused on participants taking it once they develop a cold.

In 30 studies comparing the length of colds in people regularly taking at least 200 milligrams of vitamin C daily, there was a consistent reduction in the duration of common cold symptoms.

However, the effect was small and equates to about half a day less in adults, and half to one day less in children. These types of studies also found a very minor reduction in the amount of time needed off work or school.

Among studies where vitamin C was only started once a cold had developed, there was no difference in duration or severity of a cold.

There are some risks to taking vitamin C supplements. They can increase the risk of kidney stones in men, and shouldn’t be taken by people with the iron storage disease haemochromatosis, as vitamin C increases iron absorption.




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Special considerations

Although in the general population vitamin C has no impact on the number of colds people get, there is an exception. For people who are very physically active – such as marathon runners, skiers and soldiers exercising in very cold conditions – vitamin C halved their chance of getting a cold.

Many people take vitamin C supplements in hope it will treat their cold.
From shutterstock.com

A few studies have also found some benefit from vitamin C supplements of at least 200 milligrams a day for preventing colds among those with pneumonia.

However, taking vitamin E supplements in combination with a high intake of vitamin C from food markedly increased the risk of pneumonia.

Zinc

A review of studies testing zinc supplements in healthy adults found starting daily supplements of at least 75 milligrams within 24 hours of the onset of a cold shortened the duration by up to two days or by about one-third. It made no difference to the severity of the cold.

There was some variability in the results across trials, with insufficient evidence related to preventing colds. Researchers suggested that for some people, the side effects such as nausea or a bad taste from zinc lozenges might outweigh the benefits.

Take care to stop zinc supplements as soon as your cold resolves because taking too much zinc can trigger a copper deficiency leading to anaemia, low white blood cell count, and memory problems.

Garlic

Only one study has tested the impact of garlic on the common cold. Researchers asked 146 people to take garlic supplements or a placebo daily for 12 weeks. They then tallied the number and duration of their colds.

The group that took garlic reported fewer colds than those who took the placebo. The duration of colds was the same in both groups, but some people had an adverse reaction to the garlic, such as a rash, or found the garlic odour unpleasant.

Because there is only one trial, we need to be cautious about recommending garlic to prevent or treat colds. We also need to be cautious about interpreting the results because the colds were tracked using self-report, which could be biased.




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Probiotics

In a review of 13 trials of probiotic supplements that included more than 3,700 children, adults and older adults, those taking supplements were less likely to get a cold.

Their colds were also likely to be of shorter duration and less severe, in terms of the number of school or work days missed.

There is some evidence that probiotics, which can be found in yoghurt, may reduce the incidence of colds.
From shutterstock.com

Most supplements were milk-based products such as yoghurt. Only three studies used powders, while two used capsules.

The quality of the all the probiotic studies, however, was very poor, with bias and limitations. This means the results need to be interpreted with caution.

Echinacea

Echinacea is a group of flowering plants commonly found in North America. These days you can buy echinacea products in capsules, tablets or drops.

A review of echinacea products found they provide no benefit in treating colds. However, the authors indicated some echinacea products may possibly have a weak benefit, and further research is needed.

Chicken soup

Yep, I’ve saved the best until last.

In a novel experiment on 15 healthy adults, researchers measured the participants’ nasal mucus flow velocity – our ability to break down and expel mucus to breathe more clearly. They tested how runny participants’ noses were after sipping either hot water, hot chicken soup or cold water, or sucking them through a straw.

Sipping hot water or chicken soup made participants’ noses run more than cold water, but sipping chicken soup worked the best. The researchers attributed this to the chicken soup stimulating smell and/or taste receptors, which then increased nasal mucus flow.

Another study on chicken soup found it can help fight infection and recovery from respiratory tract infections.

The ConversationOther researchers have shown comfort foods, such as chicken soup, can help us feel better.

Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle

This article was originally published on The Conversation. Read the original article.