Evening star., 1952-10-20

has would be temporary, for II
decays a few weeks after being
introduced into another persons
blood.
Risks Even in Mild Form.
There are two approaches tc
producing a vaccine.
One is to develop a mild strain
of the disease, which will give q
person a mild case and make him
immune. Such a mild strain has
been developed for the Lansing
type of polio. But there are pos
sible risks in using even a mild
form of polio virus. And it is
very difficult to produce a mild
form of all three types of polio.
A vaccine must contain all three
forms, because all three types OF
virus are so prevalent.
The other approach Is to make
the viruses inert, by using chem
ical, formalin, which destroys
their ability to produce disease
yet spares the ability to produce
antibodies.
DR. Howe did that.
He gave each of the three polio
types to different groups of mon
keys after they were severely para
lyzed. he removed the spinal cords,
ground them into thin broth,
and isolated the virus material in
a centerifuge.
A large monkey spinal cord, di-
luted 10 times, produces enough
vaccine for 20 children.
The three broths were combined
with forrnalin, to kill the viruses
The triple vaccine was given first
to monkeys. to be sure it was
harmless.
The vaccine was injected into
the muscle of children. AS a double
safety factor, they were also given
doses of gamma globulin before
the experiment, to combat any
infection that might develop. None
did. ~ -
Caused No Ill Effects.
The vaccine was administered ir
two doses. about three months
apart, and caused no discomfort
or temperature.
The crux of the experiment
was the amount of the three kinds
of antibodies-to fight the three
types of polio-found in the chill
dren's blood later.
The amount of Lansing virus
|antibody in every case compared
favorably with the amounts needed
to protect monkeys against the
Lansing form of polio.
All had more Leon-type anti.
body than Lansing. The Brunhildt
antibody level was poorest-only
two children showed any-but ir
this respect. they were like the
chimpanzees.
The amount of antibodies
needed to immunize against Leon
and Brunhilde strains Of virus is
not known.
Blood tests six months after the
first incubation showed that the
|antibody levels or amounts hae
dropped, but that most of the
children still had some anti
bodies.
There are still problems ahead
to be solved in the laboratory. One
lis to test new chemicals to kill
the virus. Another is to learr
how much antibody is needed II
Iimmunize against the Leon anc
Brunhilde strains of virus.
Another is to get large amount.
Iof polio virus. if mass vaccina.
tions are ever to become feasible
Three years ago, DR.. John En-
ders of Harvard found that viruse
could be grown in test tubes OF
several types of tissue. The poll
laboratory at Hopkins now has ,
test farm growing polio viruses.
discovery that at least one typ
of virus can be grown in hen egg
was announced recently by Dl
Herald Cox of Lederle Laborato
ries. This opens the prospect o
cheaply growing abundant sup
plies of virus for vaccines.)
DR.. Howe stressed that the hu
man trials are the elimination o
10 years of painstaking research
supported by the March of Dimes
by a team of researchers, includ
ing Drs. Kenneth F. Maxcy, Isa
ibel Morgan and DR.. Bodian.