LIVE POLIO IRUS VACCINES

312
Efficacy-Laboratory Evidence
child; negative "skips" in the series of positives
were encountered in six of these 24 children.
The duration of fecal excretion in these babies
appears to be somewhat shorter than is usually
observed following the administration of the
Sabin vaccine strains, and there is, moreover, a
suggestion that duration may be somewhat longer
among 30-day-old babies (subgroup 5a) than
among two-three-day olds (subgroup la), all of
whom were fed the same dose of Type 1. By
contrast, our previous observations of orally vaccinated
older children and adults 8 showed the
substantially longer mean and median durations
summarized in Table 4.
TABLE 4. DURATION OF FECAL EXCRETION OF
"SABIN VACCINE" VIRUSES FOLLOWING INFECTION
OF OLDER CHILDREN AND ADULTS*
Virus j Number of Duration of virus excretion
type individuals Median Mean
1 2t 11 - l days 21 ca's
2 17 16 -20 " 21
3 2C 31 - !. " 39 '
* From reference (9).
All except one of the babies fed trivalent vaccine
so far have become infected with at least
one virus type. The sole exception again is not
explainable on the basis of faulty vaccine administration
or the inadequacy of fecal observation;
virus was not isolated from any of the fecal
specimens collected on nine occasions during two
weeks after feeding. Among those who did become
infected, the pattern of virus excretion has
been rather consistent, but with minor variations.
Table 5 presents the isolation results from the
first six babies studied. Note that fecal specimens
are dated from the first dose received, and
that, therefore, those receiving three doses had a
longer opportunity to excrete passively the vaccine
material itself. Type 2 appears to become
predominant in every individual. Nevertheless,
Types 1 or 3 may appear from time to time and
even, as in baby No. 61, may be excreted for a
prolonged period of time.
DISCUSSION AND CONCLUSIONS
The major purpose of this investigation was to
titrate in two-to-three-day-old infants each of the
virus types included in the "Sabin vaccine," in
order to determine the 50 per cent and 90 per
cent end-points of infection in children of this
TABLE 5.
SERIAL RECORD
OF POLIOVIRUSES
ISOLATED FROM FIRST SIX INFANTS WHO RECEIVED
UNDILUTED TRIVALENT VACCINE
Day after Poli.ovirus type(s) isolated on indicated day
first Babies given 1 dose Babies given 3 doses
vaccine Baby Baby Baby Baby Baby Baby
dose # 28 #60 61 # # 31 # 62
O O OO 0 0
1 1,3 O i,2 1,2,3 0 2,3
2 0 1,3 1],2,3 1,2,3 1,2 2,3
3 2 1 0 1,2,3 1,2 2
4 2 1 2 1,2,3 2 2
5 2,3 - 2 1,2 2 2
6 2,3 1 2 2 2,3 2
8 2 1,2 2 2 2 2
10 2 2 2 2 2 _
14 2 2 2 2 2 0
21 1 0 3 2 2 0
28 1 2 3 2 0 0
35 0 1 3 0 0 0
42 0 O 3 2 0 0
49 O O 3 O 0 0
56 O0 2 O O 0 0
63 O O3 0 0 0
70 O O 0 0 0 0