LIVE POLIO IRUS VACCINES

476
Efficacy-Field Evidence
TABLE 2.
REPORTED CASES OF POLIOMYELITIS-MAURITIUS
YEAR
No. OF CASES
PERIOD
CASE RATE
PER 100,000
MORTALITY
RATE
1945
1948/49
1952
1959
1018
552
284
97
Feb-April
Nov-Feb
March-June
June-Sept
240
128
56
15
6
5.2
1.0
o
The epidemic started while the vaccination
campaign was still on, and occurred in midwinter.
Three previous epidemics had occurred in summer
or autumn. This is the first one in midwinter.
The details are given in Table 2.
The attack rate in children of one to seven
years who had received two to three doses of Salk
vaccine, and amongst the unvaccinated was:
Vaccinated, 3 doses
Vaccinated, 2 doses
Unvaccinated
Attack rate/100,000
2.30
11.23
279.17
It is of some interest to note that the incidence
in those who had received three doses of Salk
vaccine, which was prepared in North America,
not in South Africa, was 2.3 per 100,000, two
doses 11.23, and unvaccinated 279.
These figures are slightly loaded in favor of the
vaccine because of the specific attack rate which
is not gone into here, but they do reflect a marked
degree of protection.
The attack rate in the various age groups is
shown in Table 3. It will be noted that in the
1959 epidemic, as in the previous ones, but even
more marked, most cases occurred in the under
three-year-old age group.
Vaccination. Dr. Winter arrived on 14 August
1959. After consultation with the Ministry of
Health, it was agreed that all children between
six months and 10 years should receive the vaccine.
Vaccination centers, each in charge of a
medical officer, were established and vaccination
was started on 24 August. There was a good response
and within 10 days, 195,000 children out
of an estimated population of 213,000 had been
given the vaccine. The course of the epidemic
is shown in Table 4. It will be noted that
after 29 August there were only three further
cases, and there have been no cases since then.
It is apparent that the epidemic was waning
before the feeding of the vaccine virus was begun.
However, none of the three previous epidemics
terminated so abruptly and it is possible that the
vaccination campaign played some part in bringing
it to an end.
The island was devastated by two cyclones in
February and March this year, but no outbreaks
of poliomyelitis followed in their wake, as was
the case in 1945. Professor Dick went to the
island to study the very severe epidemic which
occurred in that year. To protect against typhoid
fever resulting from the breakdown in sanitation
about 250,000 people were inoculated twice. The
Director of Medical Services has commented that
the contrast of the administration of this vaccine
impressed him with the ease of the giving of
poliovirus vaccine by mouth.
TABLE 3.
POLIOMYELITIS ATTACK RATES (PER 100,000)-MAURITIUS
YEAR
1945
1952
1959
ATTACK RATE/100,000, BY AGE GROUP
0-1 1- 2- 3- 4- 5- 6- 7- 8- 9- 10-+
400 1490 1230 1230 1300 1190 860 340 170 80 Not given
237 388 422 139 36 Not given
55 154 115 41 14 15 10 5 11 0 .94
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