Poliomyelitis

No abstract available.


Post-Inoculation
ON OCCASION, certain valuable therapeutic and prophylactic procedures may give rise to serious and unexpected sequelae. For example, in a few exceptional individuals severe and even fatal anaphylactic shock may be induced by the injection of animal antitoxic sera; encephalitis may occasionally complicate the illness of vaccination; and hepatitis may sometimes fellow the administration of human blood or serum or the use of syringes and needles contaminated by human blood. In these instances, time was required for the association between the connected events to become apparent. Indeed it was only after a century of vaccination that vaccinal encephalitis emerged as a problem.
To the foregoing there must now be added the occasional onset of paralytic poliomyelitis ffecting the injected limb of a child recently inoculated against diphtheria or whooping -cough. Since the First World War community protection against diphtheria by injections of formol toxoid has been practised in North merica with such success that anti-diphtheria Immunization was widely adopted in Europe. In Britain it became the national policy in 1940, with alum-precipitated toxoid as the officially recommended antigen. The universal c.onquest of diphtheria by artificial immuniza-tIon with toxoid, undoubtedly a triumph of pr:ventive medicine, proceeded without serious mIshaps and encouraged a similar attack on whOoping cough when a suitable vaccine became available in 1947. It was a logical development a year later to use the mixed diphtheria and whooping cough antigens in a single course of injections.
During epidemics of poliomyelitis in 1949, Geffen (1950 and Martin (1950) in London, and quite independently, McCloskey (1950) in :' 1 elb ourn e, noted that a' number of young mmunized patients developed paralysis which nvolved solely or most severely a recently inoculated limb. It was clear from the context that these children suffered from poliomyelitis and that the local paralysis, essentially a manifestation of damage to the motor cells of the anterior horn of the spinal cord, had a causal relation to the preceding injection of a prophylactic. Although the possibility of the poliomyelitis virus having been transmitted in the prophylactic itself or by way of infected needles or syringes was soon ruled out, it was thought advisable in both London and Melbourne to restrict the scope of community immunization during the further prevalence of poliomyelitis.
As a result of the London and Melbourne experience, official advice was given to medical officers of health in 1950 to suspend immunization against diphtheria and whooping cough in any area wherein poliomyelitis became exceptionally prevalent.
Although intramuscular immunizations were stopped at a very early stage during an epidemic of poliomyelitis which affected chiefly the pre-school children of South Tyneside in 1952, Grant (1953) has reported that it was then too late to prevent the appearance of a number of cases of paralysis associated with a recent inoculation.
Obviously, when a community carrying out the routine prophylaxis of children against diphtheria and whooping cough is attacked by poliomyelitis, there may be, through sheer coincidence, a number of patients who present a history of preceding inoculation and a clinical picture of poliomyelitis. Some of these will present no paralysis and others paralysis of the usual distribution but of varying severity. In the reports cited, they can usually be distin-'guished from the cases presenting .the severe focal palsy of true post-inoculation poliomyelitis, the so-called " double event". In the latter group paralysis, maximal or limited to the muscles underlying the site of inoculation, followed within approximately a month afterwards, or to be more specific within extreme limits of 5-58 days, and commonly within 7-16 days. In a statistical inquiry covering polio-myelitis in many areas in England, where the left arm is traditionally favoured for inoculation, Hill and Knowelden ('950) found that the paralysis in children who had been inoculated within the preceding month was more frequent in the left arm than in the right, and affected the arms more often than the legs, whereas in children not recently inoculated, the incidence of paralysis affected the right and left arms equally and the legs two to three times more frequently than the arms. These authors concluded that the misfortune of poliomyelitis involving an inoculated limb occurred more frequently within a month after the administration of a prophylactic· than could be attributed to chance. During the epidemic on South Tyneside, it was found that recent inoculation doubled the risk of contracting poliomyelitis in children of the age group usually selected for primary immunization.
Although post-inoculation poliomyelitis, as defined, has occurred most commonly and severely after the use of whooping cough vaccine, alone or combined with diphtheria toxoid, it has also followed the use of the common diphtheria prophylactic, alum-precipitated toxoid. All of these antigens are most suitably given by intramuscular injection. Martin and McCloskey also quote very rare instances of similar local paralysis following the injection of other substances such as penicillin, enteric vaccine and diphtheria toxoid antitoxin floccules . It seems then that the local trauma of injection must in some obscure way predispose the anatomically related portion of the spinal cord to an attack by the poliomyelitis virus, which must also be present in the system of the patient to produce the syndrome. Although the behaviour and mode of transmission of poliomyelitis is still very obscure, all the evidence suggests that the ascertained cases, ranging from the abortive and non-paralytic to the most severe paralytic forms, are but the witnesses to a more widely spread silent infestation of the population by the virus , for it has been demonstrated in the blood and faeces of symptomless contacts and other persons. It is therefore postulated that the neurone damage of postinoculation poliomyelitis is a reflection of a local trauma which will vary in degree with the quantity and quality of the substance injected. What is not understood is the observed tendency for the paralysis in some of these cases to spread to involve the opposite limb and other muscles of the trunk and limbs, although remaining most severe in the muscles of the site injected.
Alum seems to be the common factor in the prophylactic antigens incriminated in postinoculation poliomyelitis. In America, where formol toxoid was used, post-inoculation paralysis was not noticed although there were many epidemics of poliomyelitis during the great immunization experiment. It is probable then that it is this mineral that makes these products unsuitable for subcutaneous injection, for they are apt to cause local inflammatory reactions. Yet they must produce some local damage when given intramuscularly, and it is noteworthy too that the muscles in the site of the inoculation in these cases tend to be much more severely paralysed and much slower to recover than the other muscles involved.
As post-inoculation poliomyelitis is an extremely rare complication among the thousands of inoculations that have been carried out and has not so far produced any fatality, it could not be seriously suggested that protection against diphtheria or whooping cough should be withdrawn altogether simply because poliomyelitis has shown a greatly increased prevalence in the last seven years. Since poliomyelitis is a disease of the summer months, it might be possible to introduce a corresponding close season for inoculation, but it is doubtful if poliomyelitis is sufficiently prevalent each year III every area in the country to justify such a serious interference with the successful campaign of preventive inoculation. On the other hand, to continue immunization procedures locally until poliomyelitis has become exceptionally prevalent would invite the occurrence of some of these catastrophes. The medical officer of health is by law armed with an exact knowledge ?f the incidence of poliomyelitis in his area and IS usually administratively responsible for the conduct of immunization. When he becomes aware of confirmed poliomyelitis in his district, he can halt immunization procedures for a period to observe the trend of prevalence and thereafter adapt the local campaign in accordance with the behaviour of the disease. To do this Successfully he must have the complete cooperation of his colleagues, both general practihoners and specialists, first in notification of the disease and secondly in following his advice regarding immunization. In this connection it must be obvious that there are possible medicolegal implications in post-inoculation poliomyelitis. Already a medical protection society (1953) has successfully dealt with a charge of negligence founded on such a case.
Although Geffen (1953) is doubtful whether the prophylactic inoculations in these cases were indeed intramuscular, for most observers the determining factor in post-inoculation poliomyelitis is the muscle damage induced by the prophylactic. The answer to the problem may therefore lie, as Bousfield (1953) suggests, in the adoption of antigens made suitable for subcutaneous injection, an ideal that can apparently be attained by the elimination of the irritant mineral content. Since the original observations, manufacturers of prophylactic antigens have done much to make their products acceptable by subcutaneous injection and it remains to be seen whether the desired end has been achieved. As a result of my experience, I recommend that prophylactic injections should always be given in the buttock or thigh.
Association between poliomyelitis and therapeutic procedures is not confined to immunization, for tonsillectomy has been indicted as an antecedent factor in the production of bulbar paralysis, to provide yet another example of the possible effect of local trauma when poliomyelitis is prevalent. In 1951, the Medical Research Council began a study of problems associated with poliomyelitis and it is to be hoped that the report, when published, will not only deal with the relation between trauma and subsequent local paralysis but will also indicate the precautions necessary to avoid these rare misfortunes of medical treatment.