Preventable Diseases at a 10-Year Low : County: Cases of measles, other illnesses have plummeted due to immunization efforts. But many 2-year-olds are in need of shots.

Rates of measles, mumps and other diseases that can be prevented by vaccines dropped to a historic low in Los Angeles County last year following intensive immunization campaigns, according to a new study.

But the number of children who are fully vaccinated against such diseases by age 2 remains significantly below target levels, keeping alive the possibility of future outbreaks, said the 1994 annual report of the county health department’s immunization program.

Only 15 cases of measles were reported last year, along with 49 of mumps and none of rubella--the lowest incidence of those diseases in a decade.

The number of measles cases has plummeted since an epidemic of the highly contagious virus killed 40 county residents--about half of them children--between 1988 and 1991. About 2,700 people were hospitalized with the disease in the same period. In 1990, the peak year of the outbreak, more than 4,000 cases were reported.

County health officials responded by distributing more than 600,000 doses of combined measles, mumps and rubella vaccine, known as MMR. Officials attribute the subsequent plunge in measles to that effort and to the fact that those who recover from measles develop permanent immunity.

“It is a major accomplishment,” said Dr. Jim Cherry, a UCLA expert on pediatric infectious diseases. He said measles is much more difficult to suppress in places where a significant portion of the population is poor and there are people who are uneducated and illegal immigrants facing language barriers.

Although most people recover completely from the fever, coughing and red skin spots of measles, some develop complications of pneumonia and encephalitis, which can be fatal.

The dramatic falloff in measles locally reflects a nationwide decline that has brought the disease tantalizingly close to eradication.

In 1993, only 312 cases were reported in the United States--the fewest since the measles vaccine was licensed for sale in 1963, according to the federal Centers for Disease Control and Prevention. The year before the vaccine came on the market, there were more than 481,000 reported cases in the U.S., including 408 deaths. Since 1992, no American has died of measles.

The county report said health officials are close to their goal of fully immunizing 98% or more of children entering kindergarten against measles, mumps, rubella, diphtheria, tetanus, pertussis and polio. For example, the level of kindergarten-age children with a full set of DTP shots--which cover diphtheria, tetanus and pertussis--is 94%.

But county officials fell far short of their target of delivering a full set of shots to 95% or more of children by the age of 2, the report said. In 1993-94, only 58% of 2-year-olds had received all legally required shots.

“Although vaccine-preventable diseases are at an historic low at this time, the danger of future outbreaks remains as long as immunization levels remain as low [among children age 2 and younger],” the report said. “It is therefore imperative that efforts to raise immunization levels in the county be continued or augmented.”

Dr. Shirley Fannin, the county’s chief of communicable-disease control, said local immunization efforts receive sufficient funds from the federal and state governments--$5.3 million in the 1994-95 fiscal year--to keep a tight rein on vaccine-preventable maladies.

But she warned that turmoil in the county Health Services Department triggered by the county’s budget crisis could stall future immunization drives, opening the door to a rise in the level of measles and other viruses.

Budget cuts in the department have reduced the number of clinics that administer vaccinations from 39 to 10, Fannin said, adding that the remaining clinics are not conveniently located for many people who need shots. The county already has turned over six clinics to private operators, and plans to do the same with more.

“I fear we’re going to have a major drop-off in the number of doses given this year because of the disruptions,” she said.

Dr. Caswell Evans, the department’s assistant director for public health programs and Fannin’s boss, said vaccinations will be given at more than just 1 clinics, but on a smaller scale. However, he said he does not know if the new clinic system will result in fewer vaccinations.

Evans said the county will experiment with using mobile immunization vans and other new ways to deliver shots. But he stressed that the success of future vaccination drives depends more on private doctors and managed-care organizations, which he said conduct far more immunizations than the county.

Although measles cases nationwide hit a record low in 1993, the number more than tripled last year, to 958 cases, according to the Centers for Disease Control.

Dr. Stephen Redd, chief of CDC’s measles elimination program, said that rise was largely the result of several outbreaks among people who were unvaccinated because they claimed religious or philosophic exemptions to legally required measles shots.

The largest outbreak, involving 247 cases in 10 states, was traced to students at a Colorado ski resort, according to a recent CDC report. The students, who attended a college in Illinois and a school in Missouri, were unvaccinated because they had religious exemptions, the CDC said.

Two other outbreaks involving people with philosophic exemptions to vaccinations occurred in Salt Lake City, Utah, (134 cases) and White Pine County, Nev. (12 cases).

The CDC also reported four cases of measles last year among people who were fully vaccinated with two properly spaced shots.

Los Angeles County also reported 46 cases of pertussis, or whooping cough, last year. That figure was down from 104 cases in 1993, but higher than the 26 cases reported in 1984.

Health officials attributed the persistence of the disease to a reluctance on the part of parents to allow their children to receive pertussis vaccinations. Such shots, while highly effective, do not protect as well as other vaccines.

The county immunization report also showed a steady drop in the number of hepatitis B cases over the past decade, with only 221 reported last year. By contrast, 1,077 cases were reported in 1992. Hepatitis B can be acquired through sexual activity, and Fannin attributed the decline in the virus partly to safe-sex practices among gay men.