HICAGO, Jan. 22 — Rubella, or German measles, a disease that once infected tens of thousands of Americans a year and was responsible for numerous birth defects, is on the verge of elimination in the United States, researchers say.

Cases of rubella have fallen to 272 as of 1999 from almost 58,000 in 1969, when the vaccine against it was introduced, according to a study by the Centers for Disease Control and Prevention that is being published in Wednesday's issue of The Journal of the American Medical Association.

Almost all cases of the disease in the United States are now among Hispanic adults born in other countries, primarily Mexico — meaning that the virus may no longer be circulating in the general United States population, said Dr. Susan E. Reef of the centers' National Immunization Program.

"What we're seeing now shows the success of the U.S. program," Dr. Reef said. "The most important thing is that we can eliminate this."

Rubella, which typically causes a mild rash, was considered harmless until the 1940's, when it was found to cause birth defects in children whose mothers were infected while pregnant. The virus can cause miscarriages and stillbirths, and, in babies, cataracts, heart defects, hearing damage and developmental delays.

Infants in the United States are routinely immunized against rubella, and in the late 1970's doctors also began vaccinating women of childbearing age.

The goal now, Dr. Reef said, should be to educate foreign-born people about rubella, ensure that doctors ask them whether they were vaccinated abroad and perhaps help other countries with vaccination programs.

As of January 2001, 44 of 47 countries in the Americas had childhood rubella vaccination programs, though most have been in effect for less than three years. The Dominican Republic, Peru and Guatemala were the holdouts.

In 1989, the United States set a goal of eliminating rubella by 2000. From 1992 through 1997, fewer than 300 cases were reported annually, with a low of 128 cases in 1995.