COLDS: PROPELLED THROUGH THE AIR?

The competing theory that colds are spread though the air by inhaling contaminated droplets released by cold victims is espoused by Dr. Elliot Dick, professor of preventive medicine at the University of Wisconsin Medical School in Madison. He and his colleagues studied groups of men with colds who played poker for twelve hours with healthy men susceptible to the viruses involved. Half the healthy men were fitted with neck collars or arm braces that kept them from touching their faces. Thus, the only way the restrained players could catch a cold was through the air.

In three of the experiments, the infection rate among those wearing restraints was 55 percent and the rate among the unrestrained players was only slightly higher, at 66 percent. However, in a fourth experiment, Dr. Dick separated the sick men and the healthy men. First, he got the men with colds to contaminate the playing cards and chips with nasal secretions. Then in a separate room twelve new healthy, unrestrained volunteers played poker with these contaminated cards and chips and were told to repeatedly touch their eyes and noses during the game. Not one of the twelve caught a cold.

According to Dr. Dick, this series of experiments strongly supports aerosol transmission of cold viruses and seriously questions their spread through hand-to-hand-to-nose contact. It is also possible that both theories are correct; different cold viruses may be spread most efficiently by different mechanisms, and the most efficient mode may depend on the circumstances. Since contaminated droplets do not travel far, you would have to be fairly close to an infected person to catch his or her cold.

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Anti-Infectives