Evening star., 1953-03-27
By Alton L. BIokesIee

ported in the Journal of the
American Medical Association.
Not one got sick.
Further Tests Needed.
BY every expectation, it would
actually make them throw off
any epidemic or invasion by live
polio virus. The vaccine protects
monkeys that way. Humans, of
course, are not Intentionally Civ
en- a dose of virus.
The next step is to try it on
more and more persons. to make
sure it is as good as it looks, DR..
Salk explained last night at
Science-presS dinner of the Ma
tional Foundation for 1nfantile
Paralysis.
There are rumors the vaccine
will be tried soon in fairly large
field tests.
But DR.. Salk, 38, said, 1--WE
have not yet had chance to de-
eide on what the next steps will
be. Plans for future steps
have not been announced. We
still have work to do before we
can go out on a broad SCALE"
Initial Tests Tragic.
Twenty years ago a vaccine
was used widely, with tragic re-
suits. Some children died, some
were paralyZed. In those days
little was known about the mys-
terious polio virus and it was not
known that there were three
dangerous types.
Tests of the new vaccine will
not be rushed too rapidly. nor
delayed unduly," said Basil
O'Connor, foundation president.
Enthusiasm about this vaccine
is plain. But DR.. Salk and other
experts tell of reasons for going
slow
1t isn't known just how long
the vaccine can protect. It is
apparently at least six to eight
weeks, probably months, maybe
years.
Gamma Globulin, the anti
bodies from blood donations,
protects only about five weeks.
It is the immediate bet for a
polio preventive this Summer.)
Scientists would like to test
any vaccine first on 1000 to
5000 or more children, to be
certain it's good.
Reactions Differ.
They know there's no perfect
drug, no perfect vaccine, because
humans are too individual. Many
react strangely to a drug that
is perfectly safe for every one
else-like people who get reac-
tions from penicillin or from
eggs or chocolate.
Ninety persons is just too
small a number. Polio experts
figure that only one child out
of every $50 will develop para
lytic polio during all their life
times.
There's an outside chance
there may be polio viruseS which
his directly at nerves, without
going through the blood first
Antibodies from a vaccine go
to the bloodstream, to stand
guard there.
Any real test of a vaccine
must be made in advance Of the
polio season, for many people
get the live polio virus without
ever becoming recognizably sick
They create their own anti
bodies. If the natural virus is
prevalent, any tests run then
wouldn't show that the vaccine
was really creating the anti
bodies.
Four Safely Checks Made.
And if one or two children al
ready had contracted the virus
and became paralyzed after get
ting the vaccine too late, the
vaccine could be blamed, quite
wrongly, as responsible.
DR.. Salk is sure the new vac
cine is safe. Four safety checks
are made before it's ever used.
But" he said, when you in
oculate children with polio vac
cine, you don't sleep well for two
or three weeks" worrying about
the chance something could go
wrong.
His work represents budding
of facts developed by many SCI
entists in years of an $18 million
March of Dimes research pro-
gram.
although progress has been
more rapid than we had any
right to expect, there will be no
vaccine available for the next
polio season." said the professor
of research bacteriology, the
father of three children.
161 Persons Tested.
DR.. Salk reported testing 161
persons, 4 to 40 years old. at two
Pennsylvania institutions, with
several kinds of vaccineS.
Seventy-one got injections of
vaccine consisting of killed
virus, of one type only, mixed
in water. Results with vaccines
OF each of the three types OF
polio this way were variable.
The mineral Oil vaccine was
best.
The viruses for the vaccine
are grown in test tubes, using
bits of monkey kidney tissue and
nutrient fluid. The harvest OF
virus is separated out carefully,
then the virus is killed by bath
ing it in formaldehyde for seven
days.
That's the first safety check.
AS second, the doctor injectS
the killed virus into the brains
of monkeys to make sure no live
New Material Found
Gold Coast experiments at Ac-
era have resulted in the develop-