LIVE POLIO IRUS VACCINES

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Discussion
Discussion
We know that it is possible to inhibit paralysis DR. GARD: I should like to remark on what
with a certain level of antibody. Is there a level Dr. Bodian just said. Actually, I reported last
of serum antibody which can be correlated with
the inhibition of virus excretion in feces?
As some of you may know, Dr. Howe found a
level which was inhibitory, namely a titer of
about 1:500.
Recently, I have attempted to analyse this
point, using passive antibody, in order to supplement
experiments I had begun about 10 years
ago.
In chimpanzees with a passive antibody level of
year at the First Conference that we had found
an effect of excessively high titers produced by
vaccination with inactivated virus.
We had to come up to titers of 1,000 or above
to find evidence of inhibition of excretion through
the intestines. This year, we planned an experiment
to try to confirm that observation, by immunizing
infants with inactivated vaccine, trying
to produce a wide enough range of antibody titers
to get any significant results.
1:500, one sees the first signs of inhibition of These results are not yet complete. I hesitate
fecal virus excretion. But this could only be to be too certain about their outcome. As things
detected by doing daily titrations of the virus in
the feces.
Inhibition of virus in the throat occurs at much
lower levels, and at levels of 1:500, we completely
eliminated the virus in the oropharynx in
animals which were nevertheless excreting virus
in the feces. It therefore seems that there is one
level of antibody which will inhibit paralysis,
and this is a very low level, presumably very
close to our ability to detect another level of
anywhere from 1:8 to 1:256, in which range the
throat excretion is dampened sharply, but in
order to show any effect on excretion in feces, we
have to get up to at least 1:500.
This does not mean that live poliovirus vaccine
does not have another type of effect on virus
excretion. It merely means that there may also
be an effect due to antibody alone.
look now, we will probably have the confirmation
of the previous observation that high titers tend
to restrict intestinal excretion of the virus.
CHAIRMAN GEAR: We now come to the paper
by Dr. Prem on "Vaccination of Pregnant Women
and Young Infants with Trivalent Oral Attenuated
Live Poliomyelitis Vaccine." This presentation
will be followed by Dr. Vonka's paper on
"The Development and Persistence of Polio Antibodies,
Measured by Different Methods of Neutralization
Test, in Young Adults Fed with 100,-
000 TCD 50 of Type 3 Attenuated Virus." After
that we shall have Dr. Voroshilova's paper on
"Virologic and Serologic Investigations of Children
Immunized with Trivalent Live Vaccine
from A. B. Sabin's Strains."