The U.S. Centers for Disease Control are recommending two significant changes in the routine for measles vaccinations - an extra shot for many infants and new vaccinations for older vaccinated children should an outbreak hit their schools.

But Utah likely will not implement the guidelines."The Utah Department of Health is reviewing the guidelines to determine what the economic impact would be in Utah," said state epidemiologist Craig Nichols. "It does appear that the guidelines are well-developed and will solve some of the major measle transmission problems, especially in inner-city areas. But there have not been major problems in Utah."

Utah, in fact, has had very few cases of measles, and most have been imported.

"It's unlikely that Utah will need to implement the guidelines, since they are specifically for outbreak control," Nichols said.

The CDC's measles specialists, who once expected to eradicate measles in the United States by 1982, now say the new measures are necessary to prevent continuing outbreaks of the disease in such large inner-city areas as Chicago, Los Angeles, Miami, Newark and New York City.

Nichols said measles outbreaks currently fall into two patterns nationally: outbreaks among infants under the current 15-month vaccination age, and outbreaks among vaccinated school-age children who turned out to be still susceptible to the measles virus.

To combat the outbreaks, the CDC's Immunization Practices Advisory Committee is now recommending these steps:

- Infants under 15 months old, in areas where recurrent measles is a problem, should get two measles shots instead of one - a shot of measles vaccine alone at 9 months, and a second dose at 15 months as part of the commonly used measles-mumps-rubella vaccine. The current recommendation is one measles immunization at 15 months of age. An alternative in large urban areas with low levels of immunization is a single dose of the measles-mumps rubella vaccine at 12 months, according to the report.

- In schools with measles outbreaks - and in nearby schools where the disease might spread - all students who received measles shots before 1980 should be vaccinated again, along with their siblings. If a school fighting a measles outbreak cannot vaccinate all of its students whose shots came before 1980 again, it should at least target students vaccinated before the age of 15 months.

The 1980 cutoff was chosen because vaccinations given before that time used a less effective vaccine and, until 1976, were given at 12 months, which was less effective than 15-month shots.

"Utah's policy has been that we would immunize children at a younger age (than 15 months) if there were an ongoing outbreak," Nichols said. "But we haven't had a problem and haven't had to implement that program."

Over the past six years, measles cases reported in the United States have ranged from a low of 1,497 cases in 1983 to a high of 6,282 cases in 1986. In 1987, the last year for which complete data is available, nearly three-fourths of the 3,652 measles cases reported occurred in children who had been vaccinated but got measles anyway - thus posing a potential threat to other susceptible children like themselves.