Dr. Winston Price isolated the first rhinovirus, the most common cold culprit, in 1956. This discovery was a critical step in understanding why a virus causes the common cold. The challenge is how to treat this virus. So far, there are no medication treatments to cure the common cold. The health care toolbox includes both over-the-counter and prescribed medications for symptomatic relief only.
The virus’s job is to infect, replicate, and invade. There are more than 200 viral strains that are known to cause colds. The most common cold virus is rhinovirus. Rhinoviruses cause 10-40% of colds. There are three distinct types of rhinoviruses and 169 different strains. In fact, some coronaviruses cause mild colds.
Respiratory syncytial virus (RSV) is more common in children and older adults. An RSV vaccine is available to prevent serious RSV infections, hospitalizations, and death in children and older adults. Human parainfluenza virus (HPIV) primarily affects children before the age of 2, but the symptoms of HPIV are mild. Unknown cold viruses account for 20-30% of common colds.
Rhinoviruses change by a process called antigenic drift. Antigenic drift creates new viral strains that are not recognized by pre-existing antibodies produced during previous colds. The question becomes how to develop a selective antiretroviral medication in this ongoing state of change. Each time a specific cold virus mutates, the new variant may be resistant to antiviral therapies.
Cold viruses (rhinoviruses)grow better in the cooler temperatures (90-95 degrees F) found in the nasal passages. The low humidity, cold, and dry air of winter weaken the nasal membranes. Cooler temperatures in the nares also suppress the immune system and reduce the body's natural defenses. Low temperatures and humidity provide a more stable environment for viruses like influenza to replicate and spread. In winter, people spend more time indoors with family and friends, who can transmit cold viruses to one another. The families who have or had kids in preschool know they face a higher risk of more than the usual 2-3 colds per year.
There are a few myths to consider. Myth: Being out in the cold weather will give you a cold. There are more viruses outdoors, but there is no evidence that spending time outdoors in cold environments increases the risk of getting a cold. Myth: Dairy products can lead to a cold. I was told that dairy products produce more mucous, which could lead to a cold. Products such as milk coat the throat, and it feels slimy like mucous. Myth: Vitamin C can help prevent a cold. Vitamin C can help with recovery from a cold. Doses of Vitamin over 500 mg are not indicated during the recovery period. Myth: Stress causes a cold. People who are chronically stressed may experience a decrease in white blood cell counts. White blood cells fight off infection. A lower white blood cell count increases the risk of a cold. Short-term stress actually increases the immune response.
Therapy for the common cold focuses on symptomatic relief and on decreasing the duration of the cold. The majority of the treatment consists of over-the-counter medications and supplements.
Many medications or supplements are ineffective in adults with cold symptoms, according to Cochrane reviews. Cochrane reviews summarize data from studies, often using meta-analysis to show if a drug works, for whom, and with what potential side effects, making them a gold standard in healthcare research. Antibiotic studies show no benefit for symptomatic duration compared to placebo. Both sedating (Benadryl) and non-sedating antihistamines (Allegra and Claritin) as monotherapy are no more effective than a placebo. Cough syrups such as Robitussin DM (guaifenesin and dextromethorphan) are no better than a placebo. Dextromethorphan may cause false positive urine drug tests for amphetamines, PCP, and opiates. Steam has been shown to offer no benefit for cold relief. Echinacea is no more effective than a placebo in reducing symptom duration or severity. Vitamins A, C, and E were no more effective than a placebo in symptom duration or severity.
Some medications or supplements are effective in adults with cold symptoms, according to Cochrane reviews. Acetaminophen 500 to 1000 mg, as a one-time dose, in small studies, shows improvement in 3-6 hours in nasal obstruction and rhinorrhea (runny nose). In a small randomized controlled trial, inhaled ipratropium (Atrovent inhaler)was found to reduce cough significantly. Atrovent inhalers are most commonly used in patients with COPD to reduce secretions. Intranasal oxymetazoline (Afrin nasal spray) showed minor improvements in symptoms of nasal congestion. Afrin was used for 10 days in the studies. A caution for Afrin is to use it for no more than three consecutive days due to a rebound in congestion with prolonged use. Nonsteroidal anti-inflammatory medications like ibuprofen (Motrin) did not affect symptoms or cough, but did improve sneezing, headache, ear, joint, and muscle pain. Zinc acetate or gluconate, in three systematic reviews, found improvement in symptom duration and mixed conclusions for cold recovery. Honey has been studied in single nighttime doses in children aged 12 months or older. The studies were flawed: the physician rated whether the child’s cough was less rather than asking the parents; they were not blinded; and the Honey Board funded the studies.
My favorite cold study was reported in CHEST 2000; 118:1150-1157. Chicken soup significantly inhibited neutrophil migration in a concentration-dependent manner. Neutrophils are the first line of defense against pathogens entering the bloodstream. Neutrophils engulf the “bad guys” and eat them up. The more chicken soup that was consumed, the greater the symptomatic relief. All the vegetables in the soup and the chicken individually exhibited inhibitory activity. This trial suggests that chicken soup may contain several substances with medicinal properties. A mild anti-inflammatory effect could be one mechanism by which the soup mitigates symptomatic upper respiratory tract infections. Commercial soups varied greatly in their inhibitory activity. The recipe in this study came from Dr. Stephen I. Rennard, MD, FCCP’s wife, Barbara.
There is some current ongoing research on the treatment of the common cold. One study I found on ClinicalTrials.gov is NCT06531707: Efficacy and Safety of the Combination of Ibuprofen/Loratadine Versus Ibuprofen or Loratadine. Future cold treatments will focus on broad-spectrum antivirals, host-directed therapies, and immunomodulators. Moving beyond targeting single viruses to blocking viral entry (e.g., ICAM-1 blockers) or hijacking host cell processes (e.g., capsid formation inhibitors) for broader effectiveness, future trials will explore compounds such as tremacamra, vapendavir, and natural extracts, alongside symptomatic relief and a better understanding of host factors.
My best advice comes from my mother and grandmother. Get lots of sleep, drink lots of fluids, and get symptom relief with antihistamine/decongestant combinations and chicken soup. In 2025, zinc lozenges may shorten the duration if used within 24 hours of symptom onset. Side effects of zinc lozenges include an unpleasant or metallic taste and nausea. Stay well and fly safe.
