New Orleans, March 11 -- The latest tests on children with the anti-polio vaccine have revealed that the vaccine provides the body with lasting defensive powers against the three types of viruses causing the disease, it was reported tonight.

This was described as the long-sought answer to a vital question, making it practically certain not only that the vaccine will produce effective immunity against all three types of polio but also that the immunity will be of the lasting type, possibly for the individual's lifetime.

This could mean that within the next three to five years polio, crippler of young and old alike, will join diphtheria, smallpox, typhoid and other formerly dreaded infectious diseases as plagues finally tamed and conquered by man.

The newest findings were described here tonight before the New Orleans Graduate Medical Assembly by Dr. Jones E. Salk, of the Virus Research Laboratory, University of Pittsburgh School of Medicine.

Dr. Salk developed the vaccine against the three types of polio-producing viruses, using viruses that had been rendered incapable of producing the disease while they will retained their power to produce immunity. Replying to remarks made this morning in Detroit by Dr. Albert Sabin of Cincinnati, Dr. Salk presented further evidence that this vaccine was not only safe and effective but that it was also "a practical means for inducing and maintaining antibody (immunity) formation."

Nature builds defenses against infectious diseases in two ways: It stimulates the body to produce substances known as antibodies, which serve as specific agents to neutralize and destroy the organism causing the infection. At the same time, the body, once exposed to a certain specific infectious organism, is so conditioned by nature that it responds much more quickly and effectively against a second challenge by the same infective organism.

Body Functions Noted

In other words, nature provides the body with a "memory," known as the "recall" reaction, or the "booster" response.

Dr. Salk's latest tests with his anti-polio vaccine, he reported tonight, not only produce antibodies against the three types of polio virus but also stimulate in the body the "booster" response.

Until now, he said, this was "the $64 question," since it had not been known whether the body would develop a "memory" in response to artificial stimulation by dead viruses as it does in nature in response to exposure to living viruses.

Furthermore, he reported, the triple vaccine could be produced economically on a large scale.

The three types of viruses are grown in test tubes in an artificial medium containing small bits of kidney tissue from monkeys. The kidneys of one monkey, costing only $35, it was pointed out, could provide enough virus to vaccinate 1,000 children. In other words, the kidneys of one monkey would provide 3,000 cubic centimeters of vaccine, or 3,000 doses of one cubic centimeter each.

500,000 Tests Will Be Made

In the tests scheduled to take place this spring on 500,000 children throughout the country, under the auspices of the National Foundation for Infantile Paralysis, each child will be given three "shots" of one cubic centimeter each. The first two, or primary, "shots" will be given at intervals of one week, while the third or "booster" shot, will be given one month after the second.

Dr. Salk also replied to the question, asked b Dr. Sabin, whether the monkey kidney tissue may not produce a toxic reaction, as proteins from a foreign body have sometimes been known to do. He said the actual amount of monkey kidney tissue used is so tiny as to be completely insignificant.

In tests so far on nearly 5,000 children, he said, there has been no untoward reaction of any kind, not even a fever. One child, known to be allergic to penicillin, developed a mild case of hives.

The test tubes in which the viruses are cultured contain penicillin to prevent bacterial spoilage.

The results of continuing studies in human subjects, Dr. Salk reported, indicate the following:

"That by the proper use of a suitably prepared non-infectious [dead] virus vaccine, antibody [immunity] can be induced readily in amounts equal to that resulting from natural infection [by live viruses]: And, that, in many instances, concentration of antibody in the blood stream can be raised to levels beyond that which may be regarded as an average response to the naturally acquired infection.

"The immunologic mechanism is altered by primary immunization [with killed non-infectious viruses] in a manner similar to that observed in persons who have had a natural infection.

"That these effects can be achieved with small doses of vaccine and with few injections."

The question still remaining to be answered, Dr. Salk said, is the proper interval between the primary, conditioning "shot" and the "booster" shot, and whether lasting immunity can be given with one single injection.

In case the latter proves to be true, it would mean that the single injection with dead virus would create in the body a "memory" that would enable it to respond quickly and effectively against a challenge of living virus in a natural infection. Such a challenge would then be the equivalent of the "booster" injection.