LIVE POLIO IRUS VACCINES

374 Discussion
374 Discussion~~~~~
There were a few persons whose antibody
titers did drop, but the great majority showed
an antibody rise of fourfold or greater. In calculating
booster effect, we counted only antibody
increases of fourfold or greater. As I
explained previously, our tests were carried out
using two tubes per dilution and fourfold
dilutions.
I think that our tests are, with minor differences,
rather comparable to the New Haven test.
We count only the original serum dilution in
recording our results. We now have studies in
progress correlating virus excretion with antibody
rise.
If you wish to see the conversion charts, I
shall be glad to have them projected, provided
the Chairman wishes to do so.
At this point I should like to ask Dr. Langmuir
how he accounts for the fact that 47 per cent of
all paralytic cases in Massachusetts last year
occurred in triple vaccinates. 1 think that is
something that seriously needs to be considered
and explained. How does he explain the fact
that 47 per cent of all paralytic cases in Massachusetts
in 1959 had received three or more
injections of Salk vaccine? Most of the cases
were due to Type 3.
I think that there is an immunological explanation
for this occurrence which I reported on in
1954 and I believe that there may be a valid
explanation for this occurrence.
DR. LANGMUIR: There is no question that the
Massachusetts experience in 1959, in my judgment
at least, must be classed as a vaccine failure.
This is a unique experience in that the cases of
polio, 137 paralytic cases, have occurred across
the state in an amazingly uniform manner without
apparent concentration. Out of 55 virus isolations
from these cases, 51 have been Type 3.
We have no comparable pattern anywhere else
in the country, either in 1959 or in the past three
years. Polio elsewhere has been very largely
Type 1 and very largely concentrated in unimmunized,
residual, isolated ethnically, and distinct
groups in several cities of the country.
The most logical explanation that I know of
for the Massachusetts story is that during the
period when Massachusetts was actively engaged
in its early immunization program-which was
different from that of almost all other states of
the country because that state was late in embarking
on this program-there may well have
been issued vaccines of somewhat lower potency
because in Type 3, potency was a very real
problem for a certain period of time. We are
now investigating this, but whether or not we can
identify the actual lot numbers given in 1956
and 1957 is still somewhat problematic.
DR. Cox: I am not claiming that I can prove
the facts causing this occurrence, but I should
like to quote from a report that I published in
1954, in which I stated that "extreme caution
must be taken to prove that a killed vaccine contains
a sufficient amount of antigen to make it a
good immunizing agent, rather than a sensitizing
agent."
In studies carried out with killed lymphocytic
choriomeningitis, Rocky Mountain spotted fever,
and epidemic typhus vaccines, as well as Japanese
B vaccines, we found that preparations
which do not contain enough antigen to produce
a good immunogenic vaccine actually sensitized
the vaccinated animals and made them more
susceptible to challenge than the non-vaccinated
controls. We actually experienced this for a
period of about one year when I was in the
Public Health Service, developing the spotted
fever and typhus vaccines. Later on we found
the same thing to be true, at Lederle, with killed
Japanese B vaccines.
Frankly, I do not know of any good killed
vaccine that is a good immunizing agent, unless
it has 108 virus particles (one hundred million),
and unless it is Rocky Mountain spotted fever.
Thus, if adequate quantitative studies are not
carried out in proposed killed vaccine preparations,
more harm than good could possibly
result from their use. I do not say that this is
the explanation for the Massachusetts experience.
However, it should be kept in mind.
CHAIRMAN LÉPINE: Thank you Dr. Cox. I
suggest that we return to the question of live
virus vaccine.
DR. BODIAN: I should like to ask Dr. Cox if
he agrees that some of the conversions that he
was tabulating could have been due to transient
heterotypic responses.