The progression of multiple sclerosis can be halted by the newly available anti-viral drug interferon in tests reported today in the journal Science.

A crippling disease, multiple sclerosis (MS) causes periodic deterioration of the central nervous system, leading to paralysis and sometimes death. An estimated 123,000 Americans suffer from the disease and about 8,800 contract it every year.

Interferon "seems definitely to stop or prevent these exacerbations," said Dr. Lawrence Jacob of the Millard Fillmore Hospital in Buffalo, who did the research. "It does not cure the disease . . . but down the road we hope that patients might be given interferon immediately after diagnosis, after only one or two exacerbations. Taken at that stage, it might arrest the progression of the disease."

He said he expected many other researchers to confirm the results soon, which would allow the drug to be used on a widespread basis within a few years.

The interferon exactly reversed the normal pattern for the patients. Nine out of 10 patients treated with the drug have done better than expected in tests running over a year and half. In a control group, the condition of nine of 10 patients who did not get interferon deterioriated as predicted or did much worse than predicted.

Five of the 10 patients treated with interferon showed big gains in their condition, while the deterioration of the others was halted and they continued unchanged. But for those who did not get the drug, five of 10 got much worse.

The work is important because it may lead to a new treatment for multiple sclerosis and because it helps determine the cause of the disease. The effectiveness of interferon suggests that MS is caused by a virus that can be controlled by interferon, or possibly that a periodic failure in the body's immune system is aided by interferon.

Interferon, a substance made naturally as part of the body's defenses, is one of the most powerful anti-viral agents known. Until the biotechnology advances of the past few years, however, it has not been available in quantities for testing.

The interferon used in Jacobs's experiments was only 1 to 3 percent pure. "Now 100 percent pure interferon is available, and it might be easier to administer and more effective as well," Jacobs said.

In the periodic bouts of degeneration in the disease, the brain and spine are attacked. The frequency and severity of the attacks tend to get worse during the course of the disease, and gradual paralysis and jerking spasms worsen.

In the experiments, 10 patients were given shots of interferon twice a week for more than a year, and were compared to 10 who did not get the shots.