Federal health experts recommended Thursday that infants be immunized against hepatitis B, a potentially deadly cause of liver disease, in addition to the vaccinations they currently receive.

However, Los Angeles health officials said there does not appear to be any urgency in administering the vaccine here because the rate of infection has rapidly declined from 20.6% in 1986 to 6.7%. They said they are unlikely to launch a vaccination program in public clinics without new federal funds.

The Centers for Disease Control's Immunization Committee recommended a three-dose series of hepatitis B vaccine before a child is 18 months old. If it is administered universally, the vaccine could spell an eventual end to hepatitis B in this country, the CDC said.

Health officials acknowledged that the vaccine would increase costs. Most physicians charge $25 to $50 to inoculate a child, so adding hepatitis B to the list of shots would mean higher pediatricians' bills for parents as well as additional expense for public immunization clinics.

Dr. Shirley Fannin, who is in charge of communicable disease control for Los Angeles County, criticized the CDC's recommendation as inappropriate for the county because of the declining rate of infection, the high cost of the vaccine, and its focus on "the least likely group to show the disease--little kids." The recommendation is not mandatory.

Hepatitis B virus infects 200,000 to 300,000 Americans each year, mostly through sexual contact or shared drug needles. It also is spread easily from mother to newborn.

An estimated 1 million or more U.S. patients have been left with chronic infections that can be passed to others. In most cases, hepatitis B causes symptoms such as jaundice or abdominal pain. But in serious instances, it can cause acute liver disease, cirrhosis or liver cancer, and it kills about 5,000 Americans a year.

Dr. Harold Margolis, chief of the CDC's hepatitis division, defended the policy as a strategy that should begin to break the chain of hepatitis B transmission in about 20 years, as the babies immunized today grow into adulthood.

"This is a long-term strategy," Margolis said.

The CDC's Immunization Practices Advisory Committee, in its report, also said that while widespread vaccination of adolescents or adults would bring a quicker end to the disease, it would be substantially more expensive to vaccinate these people. Children, on the other hand, can be given the vaccine during already-recommended routine doctors' visits.