The Salk Vaccine Fiasco
BY DR. ALFRED BYRNE WHEN the results of the Salk vaccine trial were assessed statistically, the vaccine was pronounced to be effective, potent, and 'incredibly' safe. It has since proved so in Canada, where a million children have been vaccinated against polio, none of them developing para- lysis attributable to the vaccine. Yet the same type of vaccine prepared on a commercial scale in America has apparently proved incredibly dangerous; so dangerous that the British Government last week cancelled the proposed clinical trials of the Salk vaccine. What went wrong? What, or who, is to blame for the fact that so many American children injected with the Salk vaccine, and others in contact with them, after- wards developed paralytic polio, which in some cases was fatal?
It now seems clear that some of these stricken children were given injections containing the living virus. Dr. Salk based his whole case on the assumption that the virus can be inacti- vated by formaldehyde, and that there is a clear interval between the time the virus is inactivated and the time it loses its power to excite the required antibodies—a time in which the virus is safe, but still potent for vaccination purposes. In this very critical assumption, Salk turns out to have been wrong.
Last month (June) the US health authorities issued a tech- nical report on the Salk vaccine. A British scientist closely concerned with polio policy in this country, with whom it was discussed, described it as 'a terrifying document.' The epithet may be unscientific but it is horribly apt. The Surgeon General of the Health Service, Dr. Leonard Scheele, from whose department the report emerges, has attempted to reassure the American public. But the report makes it clear that the vaccine, prepared according to Dr. Salk's original specifications, can be extremely dangerous. According to the report, Dr. Salk was of the opinion that the process of inactiva- tion goes smoothly and regularly from beginning to end. The experience of manufacturers, however, suggests that the inactivation slows up as it goes along, so that it takes far longer than was first thought to render the final tiny particles of the virus inactive. In fact, there may be still a minute number of these active particles still present at the end of the, whole procedure. Several of the six manufacturers licensed to make the Salk vaccine have had the daunting experience of finding active virus—in one instance, in four out of six batches tested—in the vaccine, when it should have been safe and ready for use.
Much of the American work which went towards developing this and other anti-polio vaccines was financed by the National Fund for Infantile Paralysis, whose president, Mr. Basil O'Connor, was a business partner of the late President Roosevelt. In attempting to apportion the blame for the con- fusion in the present mass immunisation which, after starting, Stopped, restarted, and is now at a standstill again, the Fund must not be forgotten. Some months before the publication of the Francis report on last year's field trial, to which even Salk had not access, the NFIP placed an order for $9 million of the vaccine. That extravagance could be interpreted either as a benevolent gesture towards the manufacturing houses, or else it sprang from a burning but unscientific desire to get on with the vaccinating and be damned, because at that time there had still been no convincing proof that vaccines of the Salk type were clinically effective against poliomyelitis in human beings.
The Fund, which sponsored the field trials and paid for the assessment of the result, was also, alas, behind the disgustingly vulgar and misleading publicity that accompanied the announcement of the results at Ann Arbour, last April. There is a rule of conduct observed on all levels of journalism that one must not publish news which might raise false hopes or foster a false sense of security in matters pertaining to health. Such, of course, was not the intention, but that was the effect of the NFIP's exuberance in turning the announcement of the Francis report, a formal and highly technical scientific paper. into 'the greatest show on earth.' Even the selection of the day for the publication of the paper—the tenth anniversary of the death of Roosevelt, who had been a polio sufferer— smacked more of the circus than of the campus.
But when joybells rang, sirens sounded and the glad news that the Vaccine was a success was flashed across the tele- vision screens of the continent, lbw could the press be expected to present the story in its proper perspective? The newspapers seized happily on a sentence from the Francis teport that the vaccine had proved successful in warding off Paralytic polio in from 60 per cent. to 90 per cent. of cases. Carried away by the occasion, Dr. Dwight Murray, chairman of the American Association's board of trustees who, pre- sumably, had not had time to read the report, declared the Salk vaccine 'one of the greatest events in the history of medicine.' No less moved. Dr. Salk said he was 'sure' that bring vaccine was potentially 100 per cent. effective and could bring complete triumph over polio. A more cold-blooded appraisal of the results of last year's experiment would have shown that there is still no information if the vaccine is effective in infants, how long the immunity may last and what will happen if the children require to be reinjected with a vaccine whose virus has been grown from potentially danger- ous monkey kidney.
There was, however, no time for cold blood on April 12. The infectious enthusiasm of the NFIP had already spread to the. Department of Health, Education and Welfare, the long- expected resignation of whose secretary, Mrs. Oveta Culp Ho4y, took place last week (July 13) 'for personal reasons of high order.' Given a preview of the report, Mrs. Hobby's department was ready to issue licences on the big day to approved firms to manufacture the vaccine. When, later, Mrs. Hobby was sharply criticised for the way her department had' handled the vaccination programme, she made the astonishing statement that she had not anticipated the great public demand for the vaccine. It is hard to see how anyone could underestimate the effect that the NFIP's rather shameful publicity stunt would have had on the parents of America, where the problem of polio is a larger and far more personal proble— than it is here.
At mak, the health authorities checked batches of the manu- facturers' vaccines to ensure that they were safely free froth active virus.
Later, in response to public demand, the regulations were relaxed and the health authorities released a large proportion of the vaecine used this year after scrutinising the makers' records of their methods . of manufacture and testing. Other batches were tested by tissue culture and on monkeys. Now, however, it is known that the monkey test for live virus is so crude as to constitute a source of danger since it will not always, by any means, differentiate between the presence of no live virus and live virus present in small amounts. No wonder some of the more reputable American virologists have (last inonth) voted to stop using the Salk virus for this year's programme.
It was indeed a bleSsing that the newspaper strike saved the health authorities of this country from the obvious charge on the part of the unthinking of being too cautious.
The remarkable fact is that so few cases of paralysis fol- lowed the use of Salk's vaccine. The number of casualties might hate been multiplied ten- or a hundred-fold. If the British health authorities had been as impulsive\ as their American counterparts this recent American tragedy could have been reproduced here. Thank God for British phlegm !