A study of hepatitis A seropositivity in Dallas County, Texas, 1998 through 1999

This paper provides background information on the epidemiology and a descriptive analysis of infection with hepatitis A virus in Dallas County, Texas, for 1998 and 1999. Reported cases were obtained from the Dallas County Health Department, and incidence rates per 100,000 population were calculated. Persons who tested seropositive for hepatitis A virus between January 1, 1998, and December 31, 1999, were included. Variables of interest included age, sex, race, and date of occurrence. The overall incidence rate of this infection in Dallas County for 1998 was 1.9 times higher than that of the United States; in 1999, the overall rate for Dallas County increased by more than 1.6 times. Rates were significantly higher among males, highest among Hispanics, and lowest among blacks for both years. Incidence rates among age groups varied between years by increasing in people 50 years and older from 1998 to 1999 as a result of a single cafeteria-related outbreak of 150 cases in March 1999. Infection with hepatitis A virus remains the most reported vaccine-preventable disease in the United States.