LIVE POLIO IRUS VACCINES

Live Virus Vaccine Studies in Southern Africa
477
TABLE 4.
POLIOMYELITIS EPIDEMIC, 1959-MAURITIUS
JUNE JULY AUGUST
Week ending 20 27 4 11 18 25 1 8 15 22 29
No. cases 1 0 5 - 17 20 19 16 8 5 4
Subsequent to feeding virus:
SEPTEMBER
OCTOBER
Week ending 5 12 19 26
No. of cases 1 - 2 - nil.
Laboratory Studies. Before the campaign began,
samples of stools and blood from family
groups and blood from children under six years
who had not received Salk type vaccine were
taken at random from all parts of the island.
The results of the virus isolations, summarized
in Table 5, show that 216 stools were tested,
with a percentage positive rate of 33 per cent,
indicating a very wide spread of infection.
Post-epidemic, but pre-vaccination immunity
is given in Table 6, and it will be noted that
Rodrigues. Rodrigues is a small island, a
dependency of Mauritius, 300 miles further east.
It has a population of about 17,500 and a steamer
from Mauritius calls about once a month with
mail and supplies.
In an immunity survey carried out in 1957
(see Table 7), it was found that most children
under 12 years lacked immunity to Type 1 poliovirus.
In January 1958, vaccination with Salk
type vaccine was offered. However, many children
were not inoculated, and as an epidemic of
TABLE 5.
VIRUS ISOLATION-MAURITIUS
No. OF STOOLS TESTED
216
No. POSITIVE
71 (Type 1)
PERCENTAGE POSITIVE
33
TABLE 6. PRE-VACCINATION IMMUNITY,
AUGUST 1959-MAURITIUS
TOTAL
TYPE 1
TYPE 2
TYPE 3
AGE GROUP
0-5 yrs
6-10 yrs
11-15 yrs
Over 20
TESTED
113
57
6
17
113
57
6
17
o
o
o
o
40
56
6
17
73
1
o
o
33
56
6
16
80
1
0
1
193
in the 0 to 5-year-age group, of the 113 tested,
every one was immune to Type 1; 40 were immune
to Type 2; and 33 to Type 3.
So the conclusion obviously is that the epidemic
had immunized the population before the
vaccine was given.
poliomyelitis was occurring in Mauritius it was
considered desirable to immunize the population
with live virus vaccine before the epidemic strain
was introduced, as seemed likely to occur. It
was originally planned to begin this campaign
in September 1959, but this was not possible as