LIVE POLIO IRUS VACCINES

138
Safety-Field Evidence of Safety
2.4
2.2
2.0
1.8
1 1
30 145
1
30
/1
i
1
i I
I
,tl
t 20
PERIOD OF VACCINATION
NUMBER OF INDIVIDUALS VACCINATED
1.6
1.4
1.2
1.0
.
I
0.8
, 1
0.6
0.4
0.2
REGION
I
0.6
0.4
0.2
REGION II
1.2
1.0
0.8
0.6
0.4
0.2
REGION
III
1.0
REGION
IV
- -. - a -1-
1959
REGION V
FIG. 4. Morbidity per 100,000 of population of reported cases of poliomyelitis during 3-month periods.
monkey kidney-cells in a medium consisting of
Hanks' solution with 0.5 per cent lactalbumin
hydrolysate, 5 per cent horse serum, and the
usual antibiotics. Four of the monolayers were
incubated at 37 ° C. and four at 40 ° C. The
final reading was made at the eighth day and the
titers were calculated according to the method
of Reed and Muench. It was found in preliminary
titrations that the difference in titer
at both temperatures was usually less than two