Drugs v. Vaccines

Most researchers seek to conquer viral infections by vaccination, and their record has been impressive. A dozen major diseases caused by viruses have virtually succumbed to vaccines, including smallpox, yellow fever, polio and measles; rubella may be next (TIME, June 20). Some investigators, on the other hand, believe that drugs, not vaccines, will eventually conquer many other viral afflictions. Yet when the drug proponents met last week at a Manhattan symposium sponsored by the New York Academy of Sciences, they were dispirited and disaffected. The vaccinators, complained Co-Chairman Ernest C. Herrmann Jr. of the Mayo Clinic, have hogged not only the limelight but also the available funds, thereby inhibiting the development of potentially valuable antiviral drugs.

Two drugs are recognized as highly effective against specific viral diseases: idoxuridine (IUDR) for corneal infections caused by the fever-blister virus, and methisazone against smallpox. What exercised the virologists most last week was a third chemical, amantadine, an anti-influenza drug that the Food and Drug Administration has licensed, but under strict controls. Trade-named Sym-metrel by E. I. du Pont de Nemours & Co., amantadine does not cure a fullblown case of flu. But it may prevent infection if taken before exposure, and mitigate the illness if taken early enough afterward. The trouble with amantadine is that it can produce insomnia, nervousness and lightheadedness, especially in older people, who would then be liable to injury from falls.

Amantadine's effectiveness seems to be confined to the Asian A-2 strains of influenza virus. Last winter the U.S. Public Health Service, troubled by the drug's side effects, refused to approve its use against the newly emerging Hong Kong strain of A2. The stated reason was that its value had not been proved--though virologists complained at the Manhattan meeting that this was a disingenuous quibble. It could have been predicted, they said, that amantadine would prove as effective against the Hong Kong strain as it was against other A-2s.

Narrow Range. The most glowing testimonial to amantadine's value came, ironically, from the U.S.S.R.'s most famous vaccine developer, Dr. Anatoli A. Smorodintsev. The drug was given, he reported, in reduced doses of 100 mg. daily to 10,000 Russians in Leningrad, a flu epidemic area. Half of them did not develop flu at all; most of those who did had cases that were milder than average. According to Smorodintsev, the side effects were negligible--though Soviet researchers have been known to soft-pedal side effects before.

Proponents of antiviral drugs concede that a single agent, such as amantadine, is effective only against a narrow range of infections. But, they point out, that is also true of vaccines. Yet a hundred or more different viruses cause what is loosely called the common cold, and many more are responsible for other upper respiratory infections. For all virologists, the hope is that the laboratories will eventually yield antiviral agents, whether drugs or vaccines, that are more broadly effective.

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