Inflammatory changes in the respiratory epithelium may persist for days or weeks after viral shedding dies down. 46 Mucous glands are activated, resulting in mild to copious exudative discharge. Blood vessels dilate and capillaries leak, causing edematous tissue and transudates in the nasal passages.
Parasympathetic neural pathways activate and coordinate local responses. 43, 44, 45 Viral replication triggers cytokine-mediated local inflammatory reactions, in addition to the recruitment of white blood cells.
Even the most positive previous trials have reported only modest symptomatic benefit, with little or no duration of benefit.Īs an infectious disease, viral ARI is characterized by the replication of viruses in the nasopharyngeal epithelium, 42 leading to a cascade of local and systemic immune responses. There is no proven cure for the common cold. Our own research indicates training in mindfulness-based stress reduction may serve to reduce incidence, duration and impact of viral ARI. 25, 26, 27, 28, 29, 30, 31 Immunization is considered impractical, as there are hundreds of strains of viruses. 18, 19, 20, 21, 22, 23, 24 In terms of prevention, behavioral strategies such as hand washing, regular exercise, and smoking avoidance are widely accepted to be at least somewhat effective. 17 Numerous factors appear to be involved, but overall, susceptibility remains poorly understood.Īlthough there still is no good proven cure for the common cold, a number of treatments have been reported to have symptom-reducing benefit in one or more randomized controlled trials (RCTs). 14, 15, 16 Some individuals are particularly prone to colds, whereas others get them infrequently. For adults, the average is two to three symptomatic colds per year and perhaps one or two asymptomatic infections. On average, children experience four to six symptomatic colds per year, in addition to several asymptomatic infections. 8, 9, 10Īlthough colds are often considered a nuisance rather than a major public health threat, even rhinovirus, the least pathogenic of the common cold viruses, may cause death among elderly and immunocompromised individuals. 5, 6, 7 Influenza causes an annual mid-winter epidemic that varies year to year, but can be a major cause of hospitalization and death. In the United States, noninfluenza ARI accounts for more than 20 million clinic visits and 40 million lost days of school and work, with total costs estimated at $40 billion, making noninfluenza ARI the seventh most expensive illness.
1, 2, 3, 4 Acute respiratory infections (ARIs) are often classified as being caused either by influenza, the most serious of the common viruses, or other viruses (noninfluenza ARI). Humanity’s most frequent illness, the common cold, is caused by acute viral infection of the upper respiratory tract.
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