(NYT Syndicate) -- Using man-made antibodies, scientists are beginning to fashion vaccine-like medications that could protect against a wide range of diseases, such as the common cold, stomach bugs and genital herpes, according to a new report.

Unlike current vaccines, which are given by injection, the new medications would be delivered to the body part in need of protection by a tablet, a squirt or a gel, researchers explained in the report published this month in the journal Emerging Infectious Diseases.

In labs across the country, researchers are exploring ways that the man-made germ busters, known as monoclonal antibodies, can be used to prevent, rather than just to treat, infections, said report co-author, Kevin Whaley, a research scientist at Johns Hopkins University in Baltimore and the research director at ReProtect, a Baltimore company that focuses on technology to protect reproductive and sexual health.

For example, Whaley said, monoclonal antibodies _ which are normally made by the human body to fight invading infections _ have already been developed to target the genital herpes virus. Researchers have demonstrated that an application of herpes antibodies blocked infection by 100 percent in a mouse study, he added.

Whaley sees another possible use for monoclonal antibodies: protecting the gut against marauding pathogens that might lurk in food or water.

"If you're traveling to Mexico or Africa where there's a high likelihood of your getting diarrhea, you could take these (as a preventative measure), for example, with every meal or every drink of water," he said.

The beauty of monoclonal antibodies is that they can be engineered to attack a particular bug, Whaley said. "They're incredibly potent and incredibly specific," he added.

The fundamental principle behind the new technology is to protect people by, in effect, sealing off areas of the body through which germs gain access, Whaley said.

The surfaces most susceptible to infection are tissues that are covered by mucus, like the lungs, the gut and the vaginal opening, he explained. So researchers are developing inhalers for the lungs, pills for the gut and creams to protect the vaginal opening.

So far, few of the new medications have been tested in humans, Whaley acknowledged. "We've gotten 100-percent protection in our animals, but that's not the same thing as a human clinical trial," he said. "It's encouraging. But we have to be cautious about animal data."

Still, one human study that looked at protecting teeth from the bacteria that cause cavities was "a stunning success," Whaley said.

The new approach to disease prevention is "an intriguing strategy," a specialist in infectious diseases noted, adding that some applications might come sooner than others.

"The concept of targeting sexually transmitted diseases like herpes and HIV is a good idea," commented Dr. David J. Tweardy, interim chief of the division of infectious diseases at the University of Pittsburgh Medical Center. "Targeting diseases in the gastrointestinal tract might be more problematic. Because the gastrointestinal tract's major purpose is to digest food and proteins, it would be difficult to design a monoclonal antibody that could resist digestion and make it, intact, through the stomach to protect the small and large bowel," he said. "That's a major obstacle, though not necessarily an insurmountable one," the Pennsylvania physician noted.

It's hard to predict when these new medications might hit the market, he said. "But obviously the animal data is very, very encouraging as a proof of principle," he added. "Still, we're a long way away from showing that herpes can be prevented in women."

Copyright 1999 The New York Times Syndicate. All rights reserved.