Dr Lynda Ware looks at the Cochrane 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.
The common cold is characterized by a runny nose, sore throat, congestion, cough, feeling unwell, and sometimes mild fever. If you have symptoms like these, there is a chance it could be COVID instead. If you’re unsure, you can find out how to access COVID tests in the UK.
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 The 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 Something 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
- Home and herbal remedies
There is reliable evidence that vitamin D supplements help prevent upper respiratory tract infections, especially in those who have a deficiency.
This comes from the review vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data (February 2017). While vitamin D is best known for its effect on calcium metabolism and for keeping our bones healthy, it appears to have benefits in preventing the common cold as well.
Vitamin C supplementation may have little or no effect on reducing the chance of getting a cold in the general The 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 Clinical 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 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 The 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 A 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.
Find out more:
- What are the effects of vitamin C for preventing or treating the common cold? (Cochrane Clinical Answer).
- Vitamin C for preventing and treating the common cold (Podcast).
Oral antihistamine / decongestant / analgesic combinations
These appear to have some benefit in relieving symptoms, but this must be weighed against side effects.
These combination preparations are widely available over-the-counter (OTC) in pharmacies and supermarkets. A Cochrane Review Oral antihistamine‐decongestant‐analgesic combinations for the common cold (January 2022) concluded that they have some general benefit in relieving symptoms and aiding recovery in adults and older children.
The most effective combination seems to be an antihistamine/decongestant combo but the benefits must be weighed against side effects such as drowsiness, dry mouth, sleep disturbance and dizziness.
Nasal decongestants used alone
Multiple doses of nasal decongestant may help a little with nasal congestion – but it is unclear how helpful this feels to the patient.
This is the conclusion of the Cochrane Review Nasal decongestants in monotherapy for the common cold (October 2016).
As with any medicine, it is important not to exceed the recommended doses.
Paracetamol may relieve nasal obstruction and runny nose, but it does not appear to help other symptoms such as sneezing, sore throat, cough and feeling unwell.
This is what the authors of a Cochrane Review Acetaminophen (paracetamol) for the common cold in adults (July 2013) conclude. They also note the need for better research to clarify just how effective paracetamol really is in providing symptom relief.
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs probably help pain associated with colds (such as headache) but not other cold symptoms.
This was the conclusion of the Cochrane Review Non‐steroidal anti‐inflammatory drugs for the common cold (September 2015). They are associated with side-effects such as irritation of the stomach lining.
Find out more: Is there randomized controlled trial evidence to support the use of non-steroidal anti-inflammatory drugs in people with the common cold? (Cochrane Clinical Answer).
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 An 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.
Find out more: What are the benefits and harms of antihistamines for people with the common cold? (Cochrane Clinical Answer).
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.
Find out more: What are the benefits and harms of antibiotics for people with the common cold and/or acute purulent rhinitis? (Cochrane Clinical Answer).
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.
Home and herbal remedies
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.
The Cochrane Review Heated, humidified air for the common cold (August 2017) concluded that the little evidence available shows that there may be little to no benefit or harm of inhaling heated humified air.
Honey is probably effective in relieving cough symptoms in children over 12 months old and may be as effective as over-the-counter preparations.
The evidence for this is in the Cochrane Review Honey for acute cough in children (April 2018). A simple remedy our grandmothers would endorse. You can read more in my blog Honey for cough in children: can it help?
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 products have not been shown to provide benefits for treating colds, although, it is possible there is a weak benefit from some Echinacea products”.
This was the conclusion of the Cochrane Review Echinacea for preventing and treating the common cold (February 2014). Despite the limited evidence, echinacea is widely used in Europe and North America for common colds.
Find out more: Echinacea for preventing and treating the common cold (Cochrane podcast).
There is currently very limited evidence on the effects of vaccines for preventing the common cold.
The Cochrane Review Vaccines for the common cold (May 2017) which looked at the evidence for potential vaccines found only one An 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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Lynda Ware has nothing to disclose.