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taken during an epidemic of poliomyelitis. In some parts of London all immunisation
was stopped while a poliomyelitis epidemic was in progress locally, in others intramuscular
injections were stopped during an epidemic while subcutaneous injections
using non-alum prophylactics continued.
During the next two or three years immunisation figures declined partly because
the publicity given to the matter made parents reluctant to come forward, and also
because of the difficulty in overtaking the arrears resulting from the cessation of activity
during poliomyelitis epidemics. The appearance of the combined diphtheria/whooping
cough prophylactics without alum which was singularly free from local reaction proved
a great stimulus to increased figures in recent years.
However, it was obvious that the final solution of this problem would have to await
the answers to a number of questions. How great was the risk in terms of the number
of injections given? Does it vary with different methods of injection, e.g., intramuscular,
subcutaneous? Does it vary with the age of the child? With the time of
the year? With the presence of an epidemic of poliomyelitis? With different types of
prophylactics? It was obvious that the answers to these questions could not be obtained
at once. In 1950 a committee of the Medical Research Council was set up to enquire
into the problem. During the next few years an enquiry was carried out by the committee
in which all public health departments co-operated. The committee reported
in 1956* and in July, 1957 the Ministry of Health issued Circular 8/57 making a number
of recommendations based on the report. The report showed that inoculation with
certain diphtheria and whooping cough prophylactics involves some slight risk of
paralysis due to poliomyelitis. The risk is greatest from April to September (i.e., it
begins before the usual poliomyelitis season) and when a combined alum-containing
prophylactic is used. There was no evidence that subcutaneous injection reduced the
risk. The way was now open for recommendations which would reduce the risk to
negligible proportions. The recommendations made by the Ministry of Health were :
(a) Alum prophylactics should not be used. This means that in addition to the
alum-containing combined prophylactic which had not been used in the Council's
service since 1950, no further use will be made of APT and PTAP.
(b) Where antigens are used in combination regard should be had to the
seasonal incidence of poliomyelitis and the season of maximum risk of provocation
paralysis. It has, therefore, been decided that in the Council's service the use of
combined antigens will cease at the beginning of April in each year. It may be
resumed at any time after August according to the amount of poliomyelitis that
is occurring. It may be that in epidemic years it may not be possible to begin
the use of combined prophylactics again until towards the end of the year.
(c) If non-alum antigens are used singly they may be used throughout the year
subject to the discretion of the medical officer of health. This means that when
the combined antigens are stopped in April it may be possible to continue prophylaxis
using single antigens.
At the time of writing it is too early to say what the effect of these changes
may be on the level of immunisation. Whilst the changes of routine are disturbing,
it may be hoped that the knowledge that steps have been taken which, in the light
of full enquiry, appear to be capable of reducing the risk to negligible proportions
may set at rest doubts that may have been in the minds of parents and members
of the staff and allow a substantial increase in the numbers of children immunised.
Vaccination
against
poliomyelitis
In January, 1956, the Ministry of Health decided to make available through the
National Health Service the small quantities of a British manufactured poliomyelitis
vaccine that were then beginning to become available, for use during the months of
May and June. Since that time there have been roughly three stages in the poliomyelitis
vaccination programme.
* Report—1956 Lancet ii—1223.
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