Short answers, pulled from the story.
The common cold is caused by viruses infecting the upper respiratory tract, with more than 200 viral types associated with it. The most common are rhinoviruses, responsible for up to 40% of cases, followed by coronaviruses, adenoviruses, enteroviruses, parainfluenza, and RSV. The viral cause of 20 to 30% of colds is unknown.
Most people recover from the common cold in seven to ten days, though some symptoms can last up to three weeks. The average duration of cough is eighteen days, and in children the cough lasts more than ten days in 35 to 40% of cases. In children, half of cases resolve in 10 days and 90% in 15 days.
There is no cure and no vaccine for the common cold. Vaccination has proven difficult because more than 200 viruses are involved and they mutate rapidly, making a broadly effective vaccine highly improbable. Treatment focuses only on relieving symptoms.
No, the common cold is a viral infection, not a result of cold weather alone. Many cold viruses are seasonal and occur more often in winter, but normal exposure to cold temperatures does not increase the risk of infection. Severe exposure causing hypothermia may increase susceptibility, though this remains controversial.
Zinc supplements taken as pills may shorten colds by up to 33% and reduce symptom severity if supplementation begins within 24 hours of the onset of symptoms. Some zinc remedies applied directly inside the nose have led to the loss of the sense of smell. Reviews in 2017 and 2018 have disagreed on whether to recommend zinc.
The common cold is transmitted by airborne droplets, by contact with nasal secretions, or through contaminated objects touched and carried to the eyes or nose. Rhinoviruses can survive on surfaces for over 18 hours. Transmission is common in daycare and schools, and people sitting close together are at greater risk.
The common cold leads to 75 to 100 million physician visits annually in the United States at a conservative cost of $7.7 billion per year. Americans spend $2.9 billion on over-the-counter drugs and $400 million on prescription medicines. The total economic impact of cold-related work loss exceeds $20 billion per year, accounting for 40% of time lost from work.