LIVE POLIO IRUS VACCINES

598
Discussion
598 Discussion
high level; and how he hopes to achieve this in
an American community, I certainly would like
to learn.
I am reminded of the paper by Dr. Pundit from
India, in which he made a careful study of smallpox
in Madras. This is a disease that many of us
claim has been eradicated quite successfully from
many parts of the world. In spite of a program
which Dr. Pundit claims is excellent for maintaining
a high proportion of vaccination in the
newborn children in Madras, smallpox breaks out
repeatedly in that city because of the large number
of immigrant children, aged one, two, and
three years, who move into the city.
Dr. Sabin, I believe, will have to look into this
problem also in Cincinnati, if he hopes to really
break the spread of polio infection in that city.
But I certainly wish him well. He is one of
the best-qualified people in the country, with a
laboratory that can support this necessarily large
amount of laboratory surveillance. I am also
glad to welcome him into continuing activity in
the poliomyelitis field, in spite of his declaration
of changing to cancer on the first of January of
next year.
DR. PAGANO: In reply to Dr. Tobin's question,
we did gather specific data concerning whether
diphtheria-pertussis-tetanus inoculations given
simultaneously with the oral administration of
live poliovirus vaccine might have a provoking
effect.
In Philadelphia, where 850 children were given
CHAT Type 1 virus, 815 W-Fox Type 3, and 335
P-712 Type 2, approximately 90 per cent of the
children also received, during the same routine
well-baby clinic visit, a DPT inoculation; many
also were given smallpox vaccination.
We saw no evidence in this group of a provoking
effect, for, as you will recall, there was no
case of paralysis in a vaccinated child.
Of course, allowance has to be made for the
numbers of children involved, so that no conclusion
can be drawn, but here is some evidence
on that point.
DR. KITAOKA: I should like to give Dr. Sabin
my comment on which type of poliovirus will be
prevalent in the future. It is true that poliovirus
Type 2 was prevalent in the southwest Pacific
areas, but Type 1 was more often recovered in the
epidemic in Taiwan and Japan. According to our
experiments, it can be foreseen which type of
poliovirus will be expected in the next epidemic
season on the basis of an estimation of the immune
state of the community during the preepidemic
season. My question is not which is
best, monovalent or trivalent. I am very anxious
to know which is the safer among the Sabin, Cox,
and Koprowski's vaccines.
DR. SOPER: I have been sitting through this
with a great deal of interest, and I have not failed
to be greatly impressed by the reports given this
week.
I feel like adding to Dr. Langmuir's greeting
to the other eradicationists, because I, too, have
been burned on the application of the eradication
concept; although, on the other hand, I have
seen some strikingly successful applications.
I am impressed with the size and volume of vaccination
reported from the USSR, and the suggestion
of the possibility of eradicating poliomyelitis.
I should like to point out, however, that as we
get well into eradication programs, after the easy
part of eradication has been done, we come to a
point of invisibility of the disease, or the insect
that we are eradicating, and at that low level we
generally encounter the greatest difficulties.
The term "epidemiology of a disappearing
disease" has been introduced in recent years,
particularly with regard to malaria, to emphasize
the need for special methods to reveal and eliminate
the final vestiges of infection.
If Dr. Langmuir's observation is backed up by
future findings, we may find that the reverse is
true for poliomyelitis; its disappearance may
come rapidly.
I should like to point out to Dr. Sabin, however,
that eradication cannot be successfully undertaken
and maintained on a small scale. In a
city with its constant daily outside contacts and
movement of population in and out, it is very
difficult to imagine a virus being completely
eliminated.
There is one word I cannot fail to utter in
reply to Dr. Dick's implication that the poliomyelitis
situation in the world is well under control
with the Salk vaccine. This may be true for