The Common Cold

A preschool-aged child may experience 3-8 colds per year. Most children fall ill 8-10 times within the first two years of life. The common cold is caused exclusively by viruses, such as rhinoviruses, parainfluenza viruses, coronaviruses, adenoviruses, etc. Over half of all cases are due to rhinovirus serotypes.

What Causes the Common Cold?

Rhinovirus was discovered in the 1950s, and even 70 years later, there is no cure or vaccine (due to the many serotypes with different proteins). Only supportive treatments are available to relieve symptoms.

How Is the Common Cold Transmitted?

Transmission occurs through direct contact between people or via droplets released by coughing, sneezing, or talking. The virus enters our body through the nose or eyes via infected droplets or contaminated hands and objects.

The incubation period (the time between infection and symptom onset) is typically around 2 days, though symptoms can appear within hours after exposure.

Why Do We Get More Colds in Cold Weather?

• Cold weather weakens nasal immunity:
  • Reduced mucus production
  • Reduced circulation of immune cells in nasal blood vessels
  • The body struggles to fight the virus at its entry point
• Close indoor contact increases transmission.
• Dry air allows viruses to survive and spread more easily.
• Less sunlight exposure reduces vitamin D production, which is crucial for immunity.
• Reduced physical activity lowers immune efficiency.

Symptoms of the Common Cold

• Sneezing
• Runny nose and congestion
• Irritability and fatigue
• Headache
• Mild fever (<39°C / 102°F)
• Sore throat (with or without a cough)

Symptoms typically last 5-7 days, and always less than 14 days.

Treatment of the Common Cold

There is no proven cure for the common cold, and antibiotics do not work because it is caused by viruses, not bacteria. The cold is a self-limiting illness, though complications like ear infections, sinusitis, and pneumonia can occur, which may require antibiotics if bacteria become involved.

Symptom Relief

• Nasal rinses with saline spray
• Decongestants for nasal relief
• Antihistamines (may reduce runny nose, but studies show mixed results)
• Honey (proven to help with cough)
• Avoid cough syrups for children under 2 years old
• Fever reducers if necessary (paracetamol/acetaminophen or ibuprofen)
• Plenty of fluids and rest

Prevention

• Hand hygiene is the most effective measure.
• Vitamin C and echinacea do not have strong evidence for preventing colds.
• Vitamin D plays a significant role in immunity, and maintaining good levels helps protect against infections.

References

• Human Rhinoviruses, Clin Microbiol Rev 2013;26:135-162
• Vitamin D and the Immune System, J Investig Med 2011;59:881-886
• American Academy of Pediatrics News, December 2011
• A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections, Viruses 2016 Sep; 8(9): 244
• Immune Changes in Humans During Cold Exposure, Journal of Applied Physiology, August 1999