Common cold

Lore & Background

The common cold is a viral infection of the upper respiratory tract, affecting the nose, throat, sinuses, and larynx. Over 200 distinct virus strains can cause it, with rhinoviruses (accounting for up to 40% of cases and having over 100 known serotypes), coronaviruses, and adenoviruses being the most frequent. The viral cause of 20–30% of colds is unknown. Transmission occurs through airborne droplets from breathing, talking, or coughing, or via contact with contaminated surfaces, where rhinoviruses can survive for over 18 hours. Risk factors include attending child care facilities, poor sleep, and psychological stress. Symptoms—such as coughing, sore throat, runny nose, sneezing, headache, fatigue, and fever—are primarily caused by the body’s immune response rather than direct tissue damage. A sore throat occurs in about 40% of cases, a cough in about 50%, and muscle aches in about 50%. Fever is uncommon in adults but frequent in infants and young children. Nasal mucus may vary from clear to yellow or green, which does not distinguish viral from bacterial infection. Symptoms typically begin within sixteen hours of exposure, peak within two to four days, and resolve in seven to ten days, though coughs may last an average of eighteen days and occasionally persist for weeks. In children, coughs last over ten days in 35–40% of cases and over 25 days in 10%. The cold is the most frequent human infectious disease; adults average two to three colds per year, while children average six to eight, with infections more common in winter.

Reader's Guide

The common cold is the most frequent infectious disease in humans, with adults averaging two to three colds per year and children six to eight. Infections occur more commonly during winter. There is no vaccine due to the rapid mutation and wide variation of viruses. Prevention relies on hand washing, avoiding touching the face with unwashed hands, and staying away from sick people. There is no cure, but symptoms can be treated: zinc may reduce duration and severity if started early; NSAIDs like ibuprofen may help with pain; antibiotics should not be used as all colds are viral. Cough medicines lack good evidence of effectiveness. The condition is self-limiting, typically resolving in seven to ten days, though cough may persist for up to three weeks. The color of mucus does not indicate viral versus bacterial infection. Herd immunity from previous exposure limits spread, and poor immune function, insufficient sleep, and malnutrition increase risk. Breastfeeding mothers with a cold can continue breastfeeding, as the virus is not transmitted through breast milk.

Did You Know?

• Well over 200 virus strains are implicated in causing the common cold.
• Symptoms are mostly due to the body's immune response, not tissue destruction by the viruses.
• The average adult gets two to three colds a year; the average child gets six to eight.
• There is no vaccine for the common cold due to rapid mutation and wide variation of viruses.