Sean Schafer, Office of Workforce and Career Development assigned to Oregon Health Services/Office of Disease Prevention and Epidemiology, Centers for Disease Control and Prevention, 800 NE Oregon, Suite 370, Portland, OR, USA, Katrina Hedberg, Office of Disease Prevention and Epidemiology, Oregon Health Services, 800 NE Oregon St., Ste. 772, Portland, OR, USA, and Paul R. Cieslak, Acute and Communicable Disease Program, Oregon Health Services, 800 NE Oregon St., Ste. 772, Portland, OR, USA.
BACKGROUND:
In 1999, because historical incidence exceeded twice the U.S. rate, CDC recommended universal childhood hepatitis A (HAV) vaccination in Oregon. Hispanics, who constitute 9% of Oregon's population (47% born abroad), have historically been at higher risk of infection. By May 2004, a total of 28% of Oregon children born in 2001 had received at least one vaccination.
OBJECTIVE:
To compare HAV incidence and demographic distribution in the pre-vaccine period (1996−1999) with the post-vaccine period (2000−2004).
METHOD:
HAV cases reported in Oregon residents during 1996−2004 were included. Incidences by age and ethnicity, obtained from case reports, were compared for pre- and post-universal-vaccination periods. Geographic analysis linked non-Hispanic cases to census block groups and calculated incidence by proportion of Hispanic residents.
RESULT:
Pre-universal-vaccine, annual HAV incidence was 15.0 cases per 100,000 population and highest among persons aged 20−39 (26.9) and 5−9 (22.0) years. Hispanics accounted for 9% of cases. Post-vaccine incidence among non-Hispanics decreased 82% (14.5 to 2.2) and declined to ³ 2.4 among each age group. Among Hispanics, incidence declined 63% (21.3 to 7.9). Declines were least (45%) among persons aged 0−19 years, whose post-vaccine incidence remained 24.9. Hispanics accounted for 26% of Oregon's cases in the post-vaccine period. Incidence was 3.7 among non-Hispanics living in areas with proportionally highest Hispanic populations and 1.5 in areas with fewest Hispanics, an incidence ratio of 2.5.
CONCLUSION:
Although HAV vaccination rates among Oregon children remain low, incidence declined substantially for all groups except Hispanic children. Risk is higher for non-Hispanics in areas with more Hispanic residents. Further HAV reductions might require alternative vaccination strategies among Hispanic immigrants and their neighbors.
LEARNING OBJECTIVES:
Describe increased HAV risk among Hispanics since universal childhood vaccination recommendations in Oregon and higher incidence among non-Hispanics living in areas with more Hispanics.
See more of Epidemiology Track Workshop: Hepatitis A: Recent Trends and Impact of Vaccination
See more of The 39th National Immunization Conference (NIC)
Recorded presentation