What causes the common cold and how can it spread?

Health officials report that the common cold is caused by a diverse group of viruses, most frequently rhinoviruses, and can spread easily through everyday contact. Clinicians and laboratory researchers note that rhinoviruses account for approximately 30–50 percent of colds; other culprits include coronaviruses, respiratory syncytial virus (RSV), adenoviruses and enteroviruses.

Infections begin when a virus reaches the nose, mouth or eyes and begins to replicate on mucous membranes. Experts explain that an infected person can be contagious before symptoms appear and for several days afterward, with viral shedding highest in the first 48 hours. Transmission occurs primarily through respiratory droplets produced when an infected person coughs, sneezes or talks, but it can also occur by touching contaminated surfaces (fomites) and then touching the face. Small-particle aerosols may contribute in enclosed or poorly ventilated spaces.

Public health guidance emphasizes practical measures to reduce spread. Frequent handwashing with soap and water, using alcohol-based hand sanitizers when soap is unavailable, routine cleaning of high-touch surfaces and avoiding close contact with sick individuals lower risk. Masking in crowded or poorly ventilated settings, improving indoor ventilation and staying home when ill further reduce transmission. There is currently no vaccine that prevents the common cold, and treatment focuses on symptom relief.

People at higher risk of complications include very young children, older adults and those with weakened immune systems or chronic respiratory conditions. Health authorities advise that people who develop severe symptoms, such as difficulty breathing or high fever, seek medical care. Clear communication from clinicians and ongoing laboratory surveillance support effective prevention and response. Researchers continue to monitor viral evolution and seasonal patterns, and public health campaigns aim to translate that evidence into accessible advice. Individuals are encouraged to consult healthcare providers for personalized guidance and to follow health recommendations during peak respiratory virus seasons.