Interferon

This marvelous broad-spectrum protective mechanism, researchers have found, begins to work within several hours after the initial viral invasion. The amount of interferon produced is usually insufficient to block all of the viruses before infection takes some toll in damaged and destroyed cells. But the substance is critical in slowing viral spread, thereby buying the body time to mount its other defenses—eater cells, killer T cells and so on—in a combined effort to terminate infection.

The effectiveness of interferon against colds was demonstrated in 1973 by Dr. Thomas Merigan of Stanford University and a group of researchers at Britain’s Common Cold Unit. They tested it on groups of volunteers who were deliberately exposed to the common rhino type of cold virus. Five of the 16 subjects who received no interferon showed significant symptoms of infection following exposure to cold viruses; none of the 16 volunteers receiving interferon showed any symptoms.

This landmark experiment showed for the first time that interferon applied artificially could block viral reproduction and spread in a human respiratory infection. It was also the first demonstration in history of successful local antiviral treatment for a respiratory infection.

Other similar studies of interferon’s power as a cold preventive were begun in 1979 with very small samples of students at the Baylor College of Medicine and Texas A&M University (page 147). In these tests the interferon was administered nasally through an apparatus that produced an aerosol mist. (A control group of volunteers was administered a salt-water aerosol.) The incidence of colds was reduced by almost half in the subjects given interferon.

Interferon, unfortunately, is not only scarce but different in every creature. Unlike antibodies, which can be taken from animals to make human vaccines, interferon from most animals has virtually no effect in humans. Thus, over the initial years of experimentation with this substance, researchers were obliged to depend upon extracts collected with great difficulty from human blood supplies. It takes some 90,000 pints of blood—as much as is donated in Seattle, Washington, in an entire year—to produce 10,000 pints of the crude material from which .014 ounce of interferon can be refined. And because the method of extraction is technically difficult, the supplying of interferon to researchers has been expensive and slow.