O.K. for Live Vaccine

By next summer, or fall at the latest, Americans will be able to take their polio vaccination in three month-apart swallows of live-virus vaccine instead of being dependent on the hypodermic needle for injections of the Salk killed-virus vaccine. Last week Surgeon General Leroy E. Burney of the U.S. Public Health Service said he had been convinced that it is now possible to manufacture a live-virus vaccine "suitable for use in the U.S." Whether this unexpectedly abrupt decision was the result of mounting evidence of safety or of pressure on the Government by live-virus advocates was not so clear.

To supplement at first, but not necessarily to replace, Dr. Jonas E. Salk's killed vaccine, the PHS Committee on Live Poliovirus Vaccine selected the live but attenuated strains developed by the University of Cincinnati's Dr. Albert Bruce Sabin. Whereas the Salk vaccine's virus particles are inactivated so that they cannot multiply, much less cause disease, the Sabin vaccine's viruses are expected to multiply. In this way, they cause a harmless infection. They do this in the digestive tract and render this part of the body an unsuitable seeding ground for future invasions of poliovirus. (The Salk vaccine triggers the production of antibodies, which circulate in the blood and protect the brain and spinal cord against paralysis, but does not sterilize the gut.)

Capsule or Teaspoon. The Sabin vaccine, which, like the Salk, is grown in monkey kidney cells, has been tested on a small scale in the U.S. but used wholesale in the U.S.S.R., where almost 80 million people have now taken it in various forms and on different dosage schedules. Full protection against all three types of polio requires three virus strains, one of each type. Dr. Sabin has tried giving them separately at short intervals, as well as in a three-in-one dose. Best results to date have been with the spaced, single-type doses, and it is expected that this regimen will be followed in the U.S. Each dose of vaccine can be given in a capsule, or as a teaspoonful of sweetish, cherry-colored liquid, or--as in current Soviet practice--built into a hard candy "sourball" with a different color for each virus type.

Before Dr. Burney's announcement, front runner among three U.S. groups seeking approval of a live-virus vaccine had been New York's Lederle Laboratories, using strains developed by Dr. Herald R. Cox. These have been put into a one-swallow, trivalent vaccine that 413,316 residents of Florida's Dade County (Miami and environs) took early this year. So far, there has been no case of paralytic polio in the county among the vaccinated, except seven which, say doctors, were already incubating when the victims took the vaccine.

Import Later. Lederle officials, who have invested $13 million in developing the Cox product, were stunned by the PHS endorsement of Sabin vaccine, which was financed by March of Dimes funds and had the powerful support of the National Foundation. Also stunned was Dr. Hilary Koprowski, an early Lederle worker on the vaccine, now at Philadelphia's Wistar Institute. At issue was the question whether the Sabin vaccine was indeed safer than the Cox and Koprowski varieties, as the PHS implied.

Foreseeing a huge public demand for the easier-to-take oral vaccine, manufacturers rushed to get into the business. Pennsylvania's Wyeth Laboratories and Indianapolis' Pitman-Moore Co. planned to make it. Lederle, with a new $2,000,000 production line, said it would accept the Washington dictate and go to work with Sabin strains. Brooklyn's Charles Pfizer Co. is making the vaccine in England, and is applying for permission to ship its product into the U.S.

Reason for the long delay before the vaccine can be generally available is the necessity for extreme care and precision in manufacture, to make sure that no virulent, disease-causing virus particles slip through. The manufacturers will have to make five separate batches and convince the PHS Division of Biologics Standards that they are all simon-pure and safe before the public gets its first prescriptions. The vaccine will be cheaper than the Salk, and the cost of administering it will be much less.

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