There is no firm evidence that Echinacea products or garlic provide any meaningful benefit in treating or preventing colds. Vitamins C and D
Vitamin C supplementation does not affect the incidence of the common cold, but may reduce its duration. There is no conclusive evidence that vitamin D supplementation is efficacious in the prevention or treatment of respiratory tract infections. Prognosis
The common cold is generally mild and self-limiting with most symptoms generally improving in a week. In children, half of cases go away in 10 days and 90% in 15 days. Severe complications, if they occur, are usually in the very old, the very young, or those who are immunosuppressed. Secondary bacterial infections may occur resulting in sinusitis, pharyngitis, or an ear infection. It is estimated that sinusitis occurs in 8% and ear infection in 30% of cases. Epidemiology
The common cold is the most common human disease and affects people all over the globe. Adults typically have two to three infections annually, and children may have six to ten colds a year (and up to twelve colds a year for school children). Rates of symptomatic infections increase in the elderly due to declining immunity.Native Americans and Inuit are more likely to be infected with colds and develop complications such as otitis media than Caucasians. This may be explained as much by issues such as poverty and overcrowding as by ethnicity. History
While the cause of the common cold was identified in the 1950s, the disease appears to have been with humanity since its early history.
Possible explanations may include cold temperature-induced changes in the respiratory system, decreased immune response, and low humidity causing an increase in viral transmission rates, perhaps due to dry air allowing small viral droplets to disperse farther and stay in the air longer.The apparent seasonality may also be due to social factors, such as people spending more time indoors, near infected people, and specifically children at school. Although normal exposure to cold does not increase ones risk of infection, severe exposure leading to significant reduction of body temperature (hypothermia) may put one at a greater risk for the common cold; although controversial, the majority of evidence suggests that it may increase susceptibility to infection. Other
Herd immunity, generated from previous exposure to cold viruses, plays an important role in limiting viral spread, as seen with younger populations that have greater rates of respiratory infections. Poor immune function is a risk factor for disease. Insufficient sleep and malnutrition have been associated with a greater risk of developing infection following rhinovirus exposure; this is believed to be due to their effects on immune function. Breast feeding decreases the risk of acute otitis media and lower respiratory tract infections among other diseases, and it is recommended that breast feeding be continued when an infant has a cold. In the developed world breast feeding may not be protective against the common cold in and of itself. Pathophysiology
The symptoms of the common cold are believed to be primarily related to the immune response to the virus.