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Common Cold

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The Problem

In the course of a year, individuals in the United States suffer 1 billion colds, according to some estimates.


The economic impact of the common cold is enormous. The National Center for Health Statistics (NCHS) estimates that, in 1996, 62 million cases of the common cold in the United States required medical attention or resulted in restricted activity. In 1996, colds caused 45 million days of restricted activity and 22 million days lost from school, according to NCHS.

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The Causes

The Viruses. More than 200 different viruses are known to cause the symptoms of the common cold. Some, such as the rhinoviruses, seldom produce serious illnesses. Others, such as parainfluenza and respiratory syncytial virus, produce mild infections in adults but can precipitate severe lower respiratory infections in young children.






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The Cold Season



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Cold Symptoms

Symptoms of the common cold usually begin two to three days after infection and often include nasal discharge, obstruction of nasal breathing, swelling of the sinus membranes, sneezing, sore throat, cough, and headache. Fever is usually slight but can climb to 102o F in infants and young children. Cold symptoms can last from two to 14 days, but two-thirds of people recover in a week. If symptoms occur often or last much longer than two weeks, they may be the result of an allergy rather than a cold.


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How Cold Viruses Cause Disease

Viruses cause infection by overcoming the body's complex defense system. The body's first line of defense is mucus, produced by the membranes in the nose and throat. Mucus traps the material we inhale: pollen, dust, bacteria and viruses. When a virus penetrates the mucus and enters a cell, it commandeers the protein-making machinery to manufacture new viruses which, in turn, attack surrounding cells.


Kinins and other chemicals released by immune system cells in the nasal membranes are the subject of intensive research. Researchers are examining whether drugs to block them, or the receptors on cells to which they bind, might benefit people with colds.

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How Colds are Spread

  • Touching infectious respiratory secretions on skin and on environmental surfaces and then touching the eyes or nose.
  • Inhaling droplet nuclei: smaller infectious particles suspended in the air for long periods of time.

Research on rhinovirus transmission. Much of the research on the transmission of the common cold has been done with rhinoviruses, which are shed in the highest concentration in nasal secretions. Studies suggest a person is most likely to transmit rhinoviruses in the second to fourth day of infection, when the amount of virus in nasal secretions is highest. Researchers also have shown that using aspirin to treat colds increases the amount of virus shed in nasal secretions, possibly making the cold sufferer more of a hazard to others.

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Handwashing is the simplest and most effective way to keep from getting rhinovirus colds. Not touching the nose or eyes is another. Individuals with colds should always sneeze or cough into a facial tissue, and promptly throw it away. If possible, one should avoid close, prolonged exposure to persons who have colds.


A cold vaccine? The development of a vaccine that could prevent the common cold has reached an impasse because of the discovery of many different cold viruses. Each virus carries its own specific antigens, substances that induce the formation of specific protective proteins (antibodies) produced by the body. Until ways are found to combine many viral antigens in one vaccine, or take advantage of the antigenic cross-relationships that exist, prospects for a vaccine are dim. Evidence that changes occur in common-cold virus antigens further complicate development of a vaccine. Such changes occur in some influenza virus antigens and make it necessary to alter the influenza vaccine each year.

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Only symptomatic treatment is available for uncomplicated cases of the common cold: bed rest, plenty of fluids, gargling with warm salt water, petroleum jelly for a raw nose, and aspirin or acetaminophen to relieve headache or fever.

A word of caution: several studies have linked the use of aspirin to the development of Reye's syndrome in children recovering from influenza or chickenpox. Reye's syndrome is a rare but serious illness that usually occurs in children between the ages of three and 12 years. It can affect all organs of the body, but most often injures the brain and liver. While most children who survive an episode of Reye's syndrome do not suffer any lasting consequences, the illness can lead to permanent brain damage or death. The American Academy of Pediatrics recommends children and teenagers not be given aspirin or any medications containing aspirin when they have any viral illness, particularly chickenpox or influenza. Many doctors recommend these medications be used for colds in adults only when headache or fever is present. Researchers, however, have found that aspirin and acetaminophen can suppress certain immune responses and increase nasal stuffiness in adults.

Nonprescription cold remedies, including decongestants and cough suppressants, may relieve some cold symptoms but will not prevent, cure, or even shorten the duration of illness. Moreover, most have some side effects, such as drowsiness, dizziness, insomnia, or upset stomach, and should be taken with care.

Nonprescription antihistamines may have some effect in relieving inflammatory responses such as runny nose and watery eyes that are commonly associated with colds.

Antibiotics do not kill viruses. These prescription drugs should be used only for rare bacterial complications, such as sinusitis or ear infections, that can develop as secondary infections. The use of antibiotics "just in case" will not prevent secondary bacterial infections.



Inhaling steam also has been proposed as a treatment of colds on the assumption that increasing the temperature inside the nose inhibits rhinovirus replication. Recent studies found that this approach had no effect on the symptoms or amount of viral shedding in individuals with rhinovirus colds. But steam may temporarily relieve symptoms of congestion associated with colds.

Interferon-alpha has been studied extensively for the treatment of the common cold. Investigators have shown interferon, given in daily doses by nasal spray, can prevent infection and illness. Interferon, however, causes unacceptable side effects such as nosebleeds and does not appear useful in treating established colds. Most cold researchers are concentrating on other approaches to combatting cold viruses.

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The Outlook


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Common Cold