Preventing and treating the common cold: what's the evidence ...

Preventing and treating the common cold: what’s the evidence?
Dr Lynda Ware looks at the Cochrane evidenceCochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. behind 14 possible interventions for treating or preventing the common cold – is there anything that might help and what are the possible risks?
Originally published: 19 January 2017, republished 21 March 2022 with updated evidence. Page last updated December 2022 (review on vaccines updated with no change to conclusions).
Common colds usually go away by themselves, with symptoms typically lasting one to two weeks. Nonetheless, colds can lead to significant time off work and school, as well as using up doctors’ appointments.
On average, adults may get 2-4 colds per year and young children as many as 6-8. Yet despite its prevalenceThe proportion of a population who have a particular condition or characteristic. For example, the percentage of people in a city with a particular disease, or who smoke., a cure for the common cold has eluded medical science and treatmentSomething done with the aim of improving health or relieving suffering. For example, medicines, surgery, psychological and physical therapies, diet and exercise changes. is aimed at relieving symptoms. There is also no foolproof way of preventing it either.
In this blog, we look at the evidence behind interventions in four categories:
Vitamin supplements
Medicines
Home and herbal remedies
Vaccines
Vitamin supplements
Vitamin D
There is reliable evidence that vitamin D supplements help prevent upper respiratory tract infections, especially in those who have a deficiency.
Only people doing extreme exercise, like skiers, seemed to benefit from vitamin C.
Vitamin C
Vitamin C supplementation may have little or no effect on reducing the chance of getting a cold in the general populationThe group of people being studied. Populations may be defined by any characteristics e.g. where they live, age group, certain diseases., though it may be useful for people who do brief periods of extreme physical exercise.
There was great excitement in the 1970s when Linus Pauling, (a Nobel laureate twice over), concluded from placebo-controlled trialsClinical trials are research studies involving people who use healthcare services. They often compare a new or different treatment with the best treatment currently available. This is to test whether the new or different treatment is safe, effective and any better than what is currently used. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. that vitamin C could prevent and alleviate the common cold. Further research followed and a Cochrane ReviewCochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research.Vitamin C for preventing and treating the common cold (January 2013). Unfortunately, the review did not confirm Pauling’s findings.
Taking regular Vitamin C did not seem to reduce the incidenceThe number of new occurrences of something in a population over a particular period of time, e.g. the number of cases of a disease in a country over one year. of colds in the general population, although there was a modest reduction in the duration and severity of symptoms. The only people who appeared to benefit were those who undertook short bursts of extreme exercise, such as marathon runners and skiers. In this group, the riskA way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of getting a cold was halved.
Studies looking at taking high-dose vitamin C at the onset of cold symptoms suggest there may be little to no consistent effect on the duration and severity of symptoms. More research is needed to clarify these findings.
Antihistamines
For adults, antihistamines probably have a limited short‐term (days one and two of treatment) beneficial effect on severity of overall cold symptoms, but not in the mid- to long term.
The Cochrane Review Antihistamines for the common cold (November 2015) found that the severity of cold symptoms probably improved on day 1 or day 2 in more people taking antihistamines than those taking placeboAn intervention that appears to be the same as that which is being assessed but does not have the active component. For example, a placebo could be a tablet made of sugar, compared with a tablet containing a medicine. (a dummy tablet). This was no longer the case from day 3 onwards and there was an increased risk of side-effects such as sleepiness.
The review authors found no evidence on antihistamines for children with colds.
Antibiotics
Antibiotics have not been shown to be helpful for the common cold and are associated with side effects and antibiotic resistance.
Common colds are caused by viruses, which are unaffected by antibiotics. The Cochrane Review Antibiotics for the common cold and acute purulent rhinitis (June 2013) looked at the use of antibiotics in the treatment of colds and purulent rhinitis (coloured mucus from the nose). Perhaps not surprisingly, antibiotics were not shown to be effective and were associated with side-effects.
Corticosteroids
There is little evidence about the effects of steroids on the common cold and, so far, it seems they may have little to no benefit.
These drugs act as powerful anti-inflammatory agents in other upper respiratory infections but the little evidence available to include in the Cochrane Review Corticosteroids for the common cold (October 2015) suggests that intranasal corticosteroids may have little to no effect on cold symptoms.
Inhaling steam may have little or no effect on symptoms of the common.
Home and herbal remedies
Steam inhalation
There is little evidence available and there may be no clear improvement or worsening of cold symptoms.
Inhaled steam has been used for decades, the thinking being that it helps drain away mucus more effectively and possibly destroys the cold virus.
Garlic
There is a lack of research evidence on the effects of garlic in people with colds.
The Cochrane Review Garlic for the common cold (November 2014) includes only one trial with 146 participants, so we can’t be sure about the potential benefits or harms of garlic for treating or preventing the common cold.
Echinacea
“Echinacea products have not been shown to provide benefits for treating colds, although, it is possible there is a weak benefit from some Echinacea products”.
Vaccines
There is currently very limited evidence on the effects of vaccines for preventing the common cold.
The Cochrane Review Vaccines for the common cold (December 2022) which looked at the evidence for potential vaccines found only one studyAn investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. comparing an adenovirus vaccine against placebo. There may be little or no difference between the vaccine and placebo in preventing the common cold, but further research is needed.
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About Lynda Ware
Lynda is a Senior Fellow in General Practice with Cochrane UK. Her background is in primary care and she was a GP partner in rural Oxfordshire for over thirty years with particular clinical interests in psychiatry and women's health. Since joining Cochrane UK in 2014, she has visited many village halls and community centres around Oxford talking to non-medical audiences about Evidence-Based Medicine (EBM) and its relevance to everyday life. With a colleague, Lynda delivers presentations for students from Years 10 to 13 to teach about EBM and to encourage critical thinking, particularly around healthcare claims made in the media. She blogs about Cochrane Reviews for the Evidently Cochrane website.
Preventing and treating the common cold: what’s the evidence? by Lynda Ware
6 Comments on this post
To tell the truth, we can treat and perceive a common cold unseriously, neglecting effective methods of treatment, but this is not a reasonable strategy. You are right that colds can lead to significant time off work and school, as well as other consequences. From my point of view, it is reasonable and important to use some of these methods in aggregate in order to achieve the maximum effect. It is so cool that you mentioned Echinacea because this product is not so widespread, but it can benefit you to a great extent. It is important to apply Echinacea correctly because this product can have a beneficial effect on the immune system, strengthening the body’s defenses. A number of studies have found that Echinacea helps to reduce the severity and duration of colds if it is used immediately after the onset of symptoms. Also, honey is a universal remedy because It includes a maximum of useful components and you are right that it may be as effective as over-the-counter preparations.
Thanks for your comment. I’ve checked in the Cochrane Library and unfortunately the Cochrane Review on zinc for the common cold has been withdrawn, while some issues that have been raised are addressed. I’m afraid I don’t know when, or whether, this will be available again.
Best wishes,
Sarah Chapman [Editor].
There is a therapy: rinse the nose with warm water every 4-6 hours (~49°C). It will kill the viruses – all of them. You can avoid a flu this way or get rid of it within 24-48 hours. It won’t help against cough thoigh. In that case pls. visit the doctor (bit rinse the nose).
It’s my method. Just add what’s known: Flu viruses die at 40°C – that’s why fever helps. They are deep under the skin, so you need to heat up your nose in the deep. That will not work with air/steam: the blood circulation can carry the heat away, it will not reach the viruses. Water persists staying in the nose, it will transfer the heat and the blood circulation is not fast enough to bring it away. This willmhe heat will kill the Viruses. As long as you stay under 50°C you won’t get hurt – but the viruses can’t survive. That’s it. No business for the pharma industry though…
There’s evidence to suggest that those who took homoeopathic remedies during the Spanish Flu Pandemic of 1919 had higher survival rates than those prescribed the “new” miracle drug of aspirin. One potential explanation is that the homoeopathic remedy did nothing at all….but did at least mean patients stayed off aspirin and its antipyretic effect, which undermined the body’s own defence against viral infection.
Just suffered a cold few days ago and yes I must agree that tissue is the best aid during the time. It is really a hassle especially I have tasks to finish. I tried several medicine and steam to make myself feel better – still lasted for couple of days. Just stay hydrated through drinking lots of water, and sipping a warm soup. Hoping that one day, a most effective way to prevent cold will come. Thanks for the information Lynda!