Virology: An Exception Extended

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In their long, frustrating search for drugs that can knock out viruses, medical researchers have almost always been stumped by one basic problem: any virus-killing chemical must penetrate the body's own cells, and it usually destroys those cells along with the virus particles lurking in them. When the first effective use of a drug against a viral disease was reported last winter (TIME, Feb. 16), it seemed like the exception that proves the rule. Idoxuridine. or IDU, was successfully used for ulcers of the cornea and nearby parts of the eye that have little or no blood supply and are relatively resistant to drug damage. The next question was whether the new drug would also kill the same virus, herpes simplex, when it infects parts of the body that have a normal blood supply.

Three doctors in Brighton, England, now think that it does. They have taken another short but promising step toward control of viral infections by using IDU against herpes simplex, the virus of fever blisters, in cases where the sores had broken out on the upper lip, nostril or cheek. Doctors usually dismiss cold sores as trivial, but the virus may cause a fatal inflammation if it spreads to the brain; it can cause blindness if it reaches the eyes. Some of the British patients already had corneal infections.

At first, the Brighton doctors report in the British Medical Journal, they tried hourly swabbing of cold sores with an IDU solution. Then they cut out the nighttime swabs to let the patients sleep. Finally the doctors switched to an ointment that was applied only four times a day. The results were equally good by all methods. The patients' recurrent cold sores had previously taken seven to 21 days to heal; now they cleared up in two to five days. Since anybody infected with herpes simplex usually carries the virus for life, though infection erupts only at intervals, the next step is to find out how long the IDU "cure" lasts.