LIVE POLIO IRUS VACCINES

164 Safety-Field Evidence of Safety
VIRUS FED
PRIOR TO
STOOL
COLLECT ON
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In.
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Type 2
Type I
Type 3
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Type 2 Ch.
In.
Type 1 C.
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Type 3 C
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0 5 10 IS 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Percent
FIG. 1.
Percentages of poliovirus isolated from six stool specimens collected from
group B individuals (vaccine group).
Ad.-Specimens from 147 adults.
Ch.-Specimens from 109 children.
In.-Specimens from 23 infants.
Only 3 stool specimens were missing, no more than 1 from any group.
for spread to the control group as compared to
the "supply" available for Types 2 and 1.
The percentage of isolations accomplished
from each of the six stool specimens received
from the group A individuals (placebo-fed during
the control period) is shown separately for
141 adults, 95 children and 30 infants in Fig. 2.
Isolations due to community spread are shown in
bar-graph form. Isolations of Type 2 and 1 from
specimens submitted after these types of poliovirus
had been fed to group A are shown at the
right of the bar-graph as percentages only. The
total of 45 isolations from group A participants,
shown in the bar-graph, Fig. 2, were from specimens
submitted by 29 individuals.
There is a progressive increase in the number
of isolations from the first to the fifth stool specimen,
and then a decrease in the number of isolations
in the sixth.
Poliovirus Type 2 was isolated from four participants
(two children, two adults) in three
group A families; the identity of these individuals,
the chronological data of the stool specimens,
and the antibody titers vs. Type 2 poliovirus
are shown in Table 2. The stool specimens
were collected 12 to 15 days after the group B
participants were fed Type 2 virus. Two of the
four persons were children in the same family
(4-3 and 4-4) and neither child had antibodies
to Type 2 virus detectable in the pre-feeding
blood specimen but both showed a significant
antibody response in the second (post-control)
blood specimen. Both adults had antibody titers
to Type 2 in the pre-study blood specimen and
neither showed an increase in titer in the postcontrol
blood specimen. Both adults had received
Salk vaccine.
In addition to the four people who picked up
Type 2 virus there were five other members of
these three families. Four of the five additional
persons had Type 2 antibodies. The fifth person,
a child of 105-2, had no Type 2 antibodies detectable
in serum dilution 1:4. There was no evi-