Infectious disease prevalence in Los Angeles county--a comparison to national estimates, 1999-2004 birth rates for U.S. teenagers reach historic lows for all age and ethnic groups.

This is the first time seroprevalence of antibody to these nine infectious diseases have been available for LAC. Differences in the race and ethnicity distribution of the United States and LAC were observed. Because disease prevalence varies by race and ethnicity, in some instances these demographic differences affected the population differences seen between the United States and LAC in the seroprevalence of the infectious diseases reported in this study. Seroprevalence for HAV was higher in LAC as compared with the United States among the total population and among the Mexican-American population. California is 1 of 11 states in which routine vaccination of children was recommended in 1999 by the Advisory Committee on Immunization Practices (ACIP) because mean incidence rates in these states were at least twice the national mean from 1987–1997 (9). Seroprevalence to CMV and T. gondii have been shown to be higher among Mexican-American persons then other race and ethnicity groups (1,3). The higher seropositivity for CMV and T. gondii among persons from LAC is due to the higher proportion of Mexican-American persons in the LAC population. No differences in seropositivity were observed when comparing Mexican-American persons in the United States and LAC for these two outcomes. No significant differences in seroprevalence between the United States and LAC were seen for measles, mumps, rubella, varicella, HSV-1, and HSV-2. Estimates of seropositivity from immunization or disease for LAC may assist in policy development, program planning, and measuring health disparities.