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61
It will here be noticed that the age group 6/10 females
is the largest group, mainly due to the infection in the
Raglan Road Girls' School.
Inevbation Period.
In the early days of the epidemic all known contacts,
whether close or indirect, were seen daily for sixteen days
after contact, but it was soon discovered that cases arose
after the sixteenth day; thereafter contacts were observed
for twenty-one days. In one case the onset of symptoms
arose twenty-two days after the case in the family had been
removed to hospital.
There are several factors affecting this incubation
period. One must be the susceptibility or the resistance of
the individual infected, and other factors are the amount
and virulence of the infecting organism. It was also shown
that in a vaccinated person the period of incubation appears
to be prolonged, and unless vaccination is carried out within
48 hours of exposure to infection it appears to have no
effect upon the onset of Smallpox, nor did it modify the
period of rash.
Vaccination.
In reporting on Smallpox and the action taken against
its spread, one regrets that the control of vaccination is not
placed with the sanitary authority. I am unable to give
particulars of the number of persons vaccinated during this
period, nor am I able to report on the severity or otherwise
of the effects of vaccination. However in the following-up
of close contacts amounting to many hundreds, during the
period of three months, practically 100 per cent. were
vaccinated or became vaccinated after contact. I would
here like to record my appreciation of the help given me
in this respect by Dr. J. H. Yolland, the Vaccinating
Officer of the Bromley Common area of the Borough.
Of the 57 cases infected 44 were unvaccinated, nine
Mere vaccinated in infancy (ages 05, 00, 53, 45, 41, 34, 27,
23, 5,), while four were vaccinated in the incubation period.
The case aged five, who had been vaccinated in infancy,
showed one doubtful scar of vaccination, and developed a
true case of Smallpox of mild degree.