LIVE POLIO IRUS VACCINES

200
Safety-Field Evidence of Safety
TABLE 11. APPEARANCE O0 m+ REVERTANT IN THE DISHES INOCULATED WITH DILUTED nm MUTANT
Each 10 fold dilution
Inoculum
(0.1 aml)
m mutant 10 -2 10 - 3 10 - 4 10 - 5 10o6 10 - 7 10 - 8 10 - 9
Name of strain (in tubes)
E-453 m 4/4' 4/4 2/4 1/4 0/4 TCID 50 /! 1 '
1.6 x 10
(in dishes) 17'- O PFU/ml 4
MEF-1 mit m+ 32 2 2.7 x 10
29 1
32 O
*Numerator: No. of C.P. positive tubes.
Denominator: No. of test tubes.
** No. of m' plaque in one dish.
Selection of m +
with agar extract
revertant from m mutant
,11.
10 6
4,
105
104
1 2 3 4 5 6
Days after infection
7 8 9 10 2nd 3rd
passage
* - to + . + = grade of cytopathogenic effect.
FIG. 1