The rate of rubella has reached an all-time low in the United States, and federal health officials say eradication of the once common childhood disease is possible in this country.

The national Centers for Disease Control in Atlanta said last week that 551 cases of the disease sometimes known as German measles were reported in the United States last year, down 12 percent from 1985 and down 99 percent since the advent of rubella vaccine.

Five percent of the nation's counties reported rubella cases last year, compared with 7 percent two years earlier, the CDC said. Elimination of rubella in this country appears feasible with intensified efforts, the Atlanta-based agency added in its weekly report.

The major concern that scientists have about rubella, a usually mild disease causing fever and rash, is the risk of congenital rubella syndrome (CRS) -- the spread of rubella infection from mother to unborn child, which can cause miscarriages and birth defects that include heart and vision disorders.

Twelve cases of congenital rubella syndrome were reported in the United States last year, up from two in 1985. Eight of the 1986 cases occurred in one cluster in New York City, eight to 10 months after a rubella outbreak there, the CDC said.

Thus far in 1987, federal health officials have received reports of two congenital rubella syndrome cases, the CDC said.

"The continued occurrence of rubella in childbearing-age populations means that potentially preventable cases of CRS will continue to occur during the next 10 to 30 years," the agency warned.

The CDC has advocated targeting vaccine programs for Americans of childbearing age.

The 551 rubella cases last year marked a dramatic drop from the 57,686 cases reported in 1969, the year that saw the first licensed rubella vaccine. The nation's rubella rate in 1986 was two cases per million residents, down from more than 250 cases per million reported in the late 1960s, the agency said.

Ten states still don't require rubella vaccine for later elementary and high-school children, and 41 states do not require proof of rubella vaccine for college students, the CDC noted.