Extra Shots Urged by CDC to Combat Measles Outbreak
The U.S. Centers for Disease Control on Thursday recommended two significant changes in the routine for measles vaccinations: an extra shot for many infants and re-vaccinations for older children if an outbreak hits their schools.
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.
“We view these recommendations positively. Clearly something needs to be done,” said Dr. Loring Dales, chief of the immunization unit for the state Department of Health Services in Berkeley. “In our large inner-city areas, such as Chicago, Los Angeles, Miami, Newark and New York City, we have had recurrent problems with large and continuing measles outbreaks in preschool-age children. We need higher immunization levels in these populations.”
Measles outbreaks nationally currently fall into two patterns: outbreaks among infants under the current 15-month vaccination age and outbreaks among vaccinated school-age children who still turn out to be susceptible to the measles virus, according to an article in Thursday’s issue of the New England Journal of Medicine.
To combat the outbreaks, the CDC’s Immunization Practices Advisory Committee recommends 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 administered measles-mumps-rubella vaccine. The current recommendation is one measles immunization at 15 months. 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 had measles shots before 1980 should be re-vaccinated, along with their siblings. If a school fighting a measles outbreak cannot re-vaccinate all students whose shots came before 1980, it should at least target students vaccinated before the age of 15 months.
The 1980 cutoff was chosen because vaccinations given before that time may not have been as effective. This was because an improved measles vaccine was introduced around that time and because, until 1976, the vaccinations came earlier in life--at 12 months. These shots of the old measles vaccine at 12 months turned out to be less effective than at 15 months.
Dr. Sonja Hutchins, a CDC measles specialist, said there was no way to predict how many children would be affected by Thursday’s recommendation. “We’re in the process of analyzing that now,” she said.
Since the measles vaccine was licensed in 1963, reported case rates in the United States have decreased by more than 98% in all age groups.
Over the last six years, measles cases reported in the United States have ranged from a low of 1,497 in 1983 and a high of 6,282 in 1986. In 1987, the last year for which complete data is available, nearly 75% 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.
In California, 813 measles cases were reported in 1987 and about 802 cases have been provisionally reported for 1988, according to Dales. More measles cases were reported in California in 1987 and 1988 than in any other state.
The majority of California cases in 1987 were in secondary school students, Dales said. The majority of cases in 1988 were in unvaccinated Latino preschool children in Los Angeles County. The current Los Angeles County outbreak so far has involved about 700 cases, most of which occurred between May and November of 1988.
