Handwashing and zinc may be best for preventing the common cold, whereas acetaminophen, ibuprofen and perhaps antihistaminedecongestant combinations are the recommended treatments, according to a review of medical literature.
The common cold affects adults approximately two to three times a year and children under age 2 approximately six times a year, according to background information in the study, which was published Jan. 27 on the website of the Canadian Medical Association Journal. Symptoms such as sore throat, stuffy or runny nose, cough and malaise are usually worse in the first three days and can last seven to 10 days, sometimes as long as three weeks.
Although self-limiting, the common cold is highly prevalent and may be debilitating, wrote Michael Allan, MD, of the University of Alberta, Edmonton, Canada, and Bruce Arroll, PhD, of the University of Auckland, New Zealand. It causes declines in function and productivity at work and may affect other activities such as driving.
Most colds are caused by viruses, with only about 5% of clinically diagnosed colds having a bacterial infection, yet antibiotics are sometimes used inappropriately for viral infections, the researchers noted.
The review, aimed at clinicians and patients, looked at available evidence for both traditional and nontraditional approaches to preventing and alleviating colds.
Clean hands: A review of 67 randomized controlled trials indicated that handwashing, a traditional public health approach, is likely effective, as are alcohol disinfectants and gloves.
Zinc: At least 2 trials indicated that children who took 10 or 15 mg of zinc sulfate daily had lower rates of colds and fewer absences from school due to colds. The authors suggest zinc may also work for adults.
Probiotics: There is some evidence that probiotics may help prevent colds, although the types and combinations of organisms varied in the studies, as did the formulations (pills, liquids, etc.), making comparison difficult.
Antihistamines: Combined with decongestants and/or pain medications, antihistamines appear to be somewhat or moderately effective in treating colds in older children but not in children under age 5 and adults.
Pain relievers: Ibuprofen and acetaminophen help with pain and fever. Ibuprofen appears better for fever in children.
Nasal sprays: Ipratropium, a drug used to treat allergies and chronic obstructive pulmonary disorder, may alleviate runny nose when used in a nasal spray but has no effect on congestion.
According to the evidence, the benefits of frequently used remedies such as ginseng, (found in ColdFX), gargling, vapor rubs and homeopathy are unclear. Cough medicines show no benefit in children but may offer slight benefit in adults. Honey has a slight effect in relieving cough symptoms in children over age 1. Vitamin C and antibiotics show no benefit, and misused antibiotics can have associated harms.
The authors note that the evidence for preventing and treating colds is often of poor quality and has inconsistent results.
Much more evidence now exists in this area, but many uncertainties remain regarding interventions to prevent and treat the common cold, they wrote. We focused on RCTs [randomized controlled trials] and systematic reviews and meta-analyses of RCTs for therapy, but few of the studies had a low risk of bias.
“However, many of the results were inconsistent and had small effects (e.g., vitamin C), which arouses suspicion that any noted benefit may represent bias rather than a true effect.
Study access (via subscription or purchase): www.cmaj.ca/content/early/2014/01/27/cmaj.121442