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What prevents, treats common cold? Study may have answer

To prevent the common cold, wash your hands and load up on zinc, Canadian researchers are reporting.

To treat a cold, however, the findings are less clear, according to the review, which was published Jan. 27 in the Canadian Medical Association Journal.

“Although self-limiting, the common cold is highly prevalent and may be debilitating. It causes declines in function and productivity at work and may affect other activities such as driving,” wrote the authors led by Dr. G Michael Allan, a family medicine physician at the University of Alberta in Canada, who directs the medical school’s evidence-based medicine program.

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 “Its impact on society and health care is large,” they added.

Medical costs associated with cold and flu can surpass more than $40 billion a year when factoring direct care like trips to the doctor or indirect costs from missed work.

Symptoms typically include a runny nose, sore throat, sneezing and coughing that can make sufferers feel miserable. That’s why people often run to the drug store at the first sign of symptoms.

But, is what they’re buying working as well as they had hoped?

The researchers first tackled which methods and treatments helped prevent the cold.

They examined two trials on children taking zinc to avoid colds. They found the number of colds, school absences and rates of antibiotic use were significantly lower in the group that took zinc compared to those who took placebos. Such trials, called randomized controlled trials, look for cause and effect, and are typically considered the gold standard for medical research.

“Although the evidence for cold prevention with zinc comes from studies involving only children, there is no biological reason why zinc would work only in children and not adults,” they concluded.

Next up in the review were probiotics, which are supplements that contain “good” bacteria thought to boost the immune system. They found probiotics might be helpful in preventing upper respiratory tract infections, citing studies of young children. But overall, the evidence was inconsistent.

Evidence showed physical interventions, such as hand-washing or using disinfectants, were found to be effective at preventing cold in the majority of results reviewed.

As for other methods, gargling with water for 15 seconds, three times per day was shown to help in one study, but researchers said a second study should confirm this before it is recommended for cold prevention. Ginseng was deemed “questionable” for preventing colds based on the available studies. No meaningful benefits towards prevention were found for average patients taking vitamin C, vitamin D and echinacea.

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 The researchers also looked at what treatments will help once a person actually gets sick with a cold.

Antihistamines and decongestants alone were not found to clinically improve cold and flu symptoms, but combinations of both drugs likely aided at curbing some symptoms in adults and older children. Still, the researchers recommended against the combination treatments for children 5 and younger, citing a lack of studies.

Prescription nasal spray, called intranasal ipratropium, was shown to curb cold symptoms. On the other hand, they carried some side effects like mouth and nasal dyness.

Over-the-counter cough meds had slightly helped adults, but those benefits were not seen in children.

Vapor rub helped kids and parents sleep, but was linked to more harms -- including burning sensations, rash and redness -- than benefits for treating cold symptoms, the researchers found.

Nonsteroidal anti-inflammatory drugs (ibuprofen) and acetaminophen appear to be effective in relieving pain and fever in people with colds, but not other symptoms. Doctors have previously warned acetaminophen may increase risk for liver damage if too much is taken, a danger during cold and flu season, since many over-the-counter drugs contain the ingredient.

A single spoonful of honey was also shown to reduce cough in young children and help them sleep.

Though zinc was shown to help prevent a cold, it didn't always work once you already contracted the virus. Zinc, taken orally, might help reduce the duration and severity of the common cold in adults, but no benefits were seen in sick kids. Zinc nasal sprays were recommended against entirely for adults and kids, due to side effects. 

The bottom line?

“The symptoms will probably linger whether you treat them or not,” Dr. Amy Espositio, a physician at Beth Israel Medical Center in New York City who was not involved in the study, said to CBS News.

Symptoms of a cold can mimic other conditions including allergies, strep throat, sinusitis and influenza, the authors pointed out. A trip to the doctor's office might clear up any confusion about what's ailing you or your family.

If you’re feeling sick with these symptoms, however, resist the temptation to call your doctor and demand antibiotics, warns CBS News chief medical correspondent Dr. Jon LaPook.

The cold and flu are viruses, whereas antibiotics treat bacterial infections. Antibiotics might be prescribed if cold symptoms do not subside for more than three days, which might be a sign of a sinus infection.

Indeed, the new review found antibiotics offered no benefits for treating the common cold.

“Viruses are not treatable by antibiotics,” LaPook said. “Every year I have to talk over and over again to patients about this.”

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