According to an old medical maxim repeated in the New England Journal of Medicine last week, symptoms of the common cold, "if treated vigorously, will go away within seven days, whereas if left alone they will disappear over the course of a week." Despite years of intensive research, that wry wisdom is still true: there is no cure for the common cold. But the Journal did have some encouraging words for snifflers. In the same issue it published two studies, one conducted at the University of Adelaide, in Australia, the other at the University of Virginia, demonstrating that use of an alpha-interferon nasal spray can prevent 40% of colds. Says Dr. Frederick Hayden, who conducted the American study: "This is, to our knowledge, the first instance where it has been possible to show prevention of transmission of colds in an ordinary household setting."
Together, the two studies involved 150 families, each with four or more members. Every time one member showed the first signs of a cold, the rest of the family was instructed to begin using a nasal spray once daily for the next seven days. Half the families were using sprays containing alpha-interferon, one of several forms of the natural antiviral agent, while the others inhaled a harmless placebo. Over a period of six to eight months, the interferon families had 40% fewer colds than the placebo group.
The drug was especially effective in preventing colds caused by rhinoviruses, the largest single group of cold-causing viruses and the kind blamed for most of the colds brought home by schoolchildren in autumn. "They are responsible for more than half of colds in the fall and spring," says Dr. Jeffrey Stritar, director of antiviral clinical research at Schering-Plough Corp. in New Jersey. Schering, which funded both studies, is one of several companies using genetic-engineering techniques to manufacture alpha-interferon.
Although the interferon sprays caused irritation and minor nasal bleeding about 10% of the time, the main drawback of the treatment is likely to be price. Schering will not discuss the current cost of its interferon, but according to a spokesman, the company hopes "to have the product at an affordable level after FDA approval," which could take months or even years to obtain. Unless the price of interferon drops substantially, its most practical use may be to protect those most endangered by colds: people with asthma, cancer patients whose resistance is low and the elderly.