Measles Surveillance Data Research Articles

Measles—United States, 1996, and the Interruption of Indigenous Transmission

As of December 30, 1996 (week 52), local and state health departments had reported a provisional total of 488 confirmed cases of measles to CDC for 1996, and the Commonwealth of Puerto Rico had reported eight cases. In addition, indigenous transmission of measles in the United States was interrupted for a prolonged period beginning in late 1996. This report summarizes measles surveillance data for 1996, which indicate a substantial proportion of cases were associated with continued international importations of measles and outbreaks among school-aged children who were not required to receive a second dose of measles-containing vaccine (MCV) to attend school.

The Impact of College Prematriculation Immunization Requirements on Risk for Measles Outbreaks

To assess whether prematriculation immunization requirements (PIRs) affect the number of measles cases on college campuses. We surveyed a stratified random sample of 880 colleges and universities to determine their immunization policies and practices and occurrence of measles outbreaks from 1988 through 1991. We merged national measles surveillance data with survey data by county to determine the risk for measles introduction on college campuses. We used logistic regression methods to estimate the effect of PIRs and assess risk factors for college measles outbreaks. A total of 3205 US colleges and universities listed in standard guides. Of selected schools, 91 (11%) of the 796 responding schools reported one or more measles cases occurring from 1988 through 1991. Schools with a state-mandated PIR were significantly less likely to report measles outbreaks of two or more cases than other institutions (adjusted relative risk [RR] = 0.30; 95% confidence interval [Cl], 0.11 to 0.84). None of the 14 schools that reported outbreaks of 10 or more cases was subject to state regulation or had a PIR specifying two doses of measles vaccine in place. Of schools with introduction of measles, residential colleges were more likely to report extensive spread of measles (five or more cases) than nonresidential colleges (RR = 35.8; 95% Cl, 2.08 to 617.0). Of public schools, 4-year programs had a higher risk of a large outbreak (five or more cases) than 2-year programs. These results strongly support current recommendations for requiring proof of vaccination of college students to decrease the risk for measles outbreaks on college campuses. State regulations mandating PIRs ensure the best protection against widespread measles transmission.

The Geographic Distribution of Measles in the United States, 1980 Through 1989

To describe the geographic distribution of measles cases in the United States by county for the 10-year period from 1980 through 1989. Ecological analysis of national measles surveillance data. Measles cases reported to the Morbidity and Mortality Weekly Report from 1980 through 1989 were analyzed. Data from the 1980 and 1990 US censuses were used to produce demographic profiles for each of the 3137 countries. Outcome variables examined included mean annual incidence and number of years reporting measles, with use of Spearman's rank correlation coefficients to examine the association between the demographic and the two outcome variables. A total of 56,775 measles cases were reported during the decade. Of the nation's 3137 counties, 1690 (53.9%) did not report any cases; only 17 (0.5%) reported measles in all 10 years. Counties reporting measles more frequently during the decade had higher median populations, population densities, and percentage of black and Hispanic populations than those counties reporting less frequently. Population size, population density, and percentage of Hispanic population were associated with number of years reporting measles and mean annual measles incidence rate. Measles cases in counties reporting measles every year predominantly occurred in unvaccinated preschoolers; cases in counties reporting less frequently predominantly occurred in vaccinated school-aged children. This analysis illustrates the focal nature of measles in the United States during the past decade. Most counties have not reported a single case of measles during the entire decade, and only 17 counties reported measles every year. Targeted strategies are needed to improve age-appropriate immunization levels among preschool-aged children living in large inner-city areas.