LIVE POLIO IRUS VACCINES

332
Efficacy-Laboratory Evidence
O/o
100
97
PRE-FEEDING TITERS
FiG. 1. Percentage of 360 Cuban children with four-fold or greater rise in antibody titers after
taking 2ml. oral trivalent poliovaccine.*
* (106.1 TCDao each type per dose.)
cine no triple negatives were left. Figure 1
shows the conversion and booster response rates
in 360 Cuban children after ingestion of the trivalent
oral vaccine. The same figures are shown
on the bar graph indicating the response of those
individuals who showed no detectable antibodies,
at least by our own methods. Thirty-two out of
35 converted to Type 1, which is 91 per cent;
15 out of 22 to Type 2, which is 68 per cent; and
33 out of 34 to Type 3, which is 97 per cent.
Now, I should like to point out that these other
figures are cumulative values. In other words,
anything with an antibody titer of 1:8, but less
than 1:16, is depicted here. As you can see, as
you go across the chart, as the antibodies are
found to increase, lesser responses to the vaccine
are found. This is what you would expect.
Group 2 comprised 123 males residing in a
closed institution in New England. They ranged
in age from 17 to 70 years, but most were in their
mid or late 20's. In this institution we believe
there were plenty of chances for rebound infections.
At the time of vaccination, the frequency
rates of seronegatives among them were
31, 31, and 32 per cent, respectively, for poliovirus
Types 1, 2, and 3. The distribution and
grouping of these seronegatives is detailed in
Table 2, and collectively they represent 115 antibody
gaps in 67 of the 123 inmates. You can see
that these are broken down into single negatives
to Types 1, 2, and 3; double negatives to 1 and
2, 1 and 3, 2 and 3; and triple negatives.
Of the 123 individuals there were 12 triple
negatives. In these columns you see the numbers
of negatives left after the vaccine was fed; thus
we had 100 per cent conversion to Type 1. Nine
individuals failed to convert to Type 2, and one
individual failed to convert to Type 3. We had
left a single double negative, an individual that
failed to respond. He was a double negative to
Types 2 and 3. No triple negatives were left.
Serum neutralization tests on specimens collected
31 days after feeding showed that 103 (89.6 per
cent) of the 115 pre-vaccination negatives became
positive as a result of oral vaccination. Ten of
the 12 residual seronegatives were for Type 2
virus, and seven of these occurred among the 12
originally triple negatives. This points up to
what we have been uniformly finding, that in the
triple negative it is more diffcult to get a positive