Researchers at Johns Hopkins University Medical School have developed a treatment that they say can prevent the potentially fatal reactions that could be experienced by an estimated 1.7 million Americans when they are stung by bees, wasps, hornets or yellow jackets.

The researchers also said, in an article published in today's edition of the New England Journal of Medicine, that the treatment for stings that has been used for almost 50 years is "essentially useless."

The new treatment, announced yesterday at a news conference in Baltimore, involves giving injections to hypersensitive persons of the venom of the insect to which they are allergic.

The venom treatment was found to be completely effective 95 percent of the time, the researchers said.

They said in the article that the so-called wholebody extracts treatment now in use, which consists of groundup insect bodies, is little more effective than placebos - fake treatment - given to volunteers.

In the experiment, 59 patients in the researchers' study were divided into three groups. One group was treated with venom, one with the whole-body extract and one received the placebo.

Only 5 percent of those treated with venom had a serious reaction to a subsequent sting, but there was virtually no difference between the group treated with the placebo and the group treated with the old whole-body medication, the researchers said.

While most people simply experience pain, swelling and reddening in the area of a sting, hypersensitive people may experience swelling in the throat or tongue - making breathing difficult or impossible - and/or spasms and severe loss of blood pressure and shock.

About 50 deaths a year are attributed to insect stings. But Dr. Martin Valentine, who with Drs. Lawrence Lichtenstein and Anne Sobotka, was one of the principal investigators on the study said the number probably is much higher.

"Most fatal stings don't have time to develop a local reaction (swelling and reddening)," Valentine said, so they may be reported as heart attackts rather than death due to an insect sting.

The researchers said they do not expect universal acclaim for their work. In fact, Valentine said, "we have received a lot of 'interesting' mail and phone calls" condemning the negative view of whole-body treatments.

Lichtenstein said he hopes the venom can be marketed commercially and made available to physicians by next summer.

The federal Food and Drug Administration is already studying a drug company's application to market the product, he said.

There are no firm cost estimates yet. But the researcher said a year's series of shots will cost in the neighborhood of $150 to $200.

Individuals who need the venom will first have to undergo a series of injections over an 8-to-10 week period and then probably will need injections on a monthly basis for an indefinite number of years.

Some researchers have believed for many years that using the venom was the way to prevent severe reactions to insect stings. It was a technique dictated by logic for to treat other kinds of allergies, physicians administer a small amount of the allergen to the patient. Likewise, to build up a immunity to a virus, such as flu, a person is given small amounts of the virus.

The whole-body treatment first came into use in 1930 after the publication of an article in a medical publication for allergists. The article reported the success of the treatment on one patient, a bee keeper.According to Lichtenstein, the practice of the past 50 years has been based on a reported experience of that one patient.