The patterns of hepatitis a epidemiology in Manitoba 1992–2003: Implications for vaccination strategies

Objectives The objective of this study is to examine annual trends in the incidence of hepatitis A virus (HAV) infection, and to evaluate the impact of the preventive measures adopted by Manitoba Health in the last decade through the use of Manitoba Provincial laboratory database. Methods Data were extracted from the database on population-based laboratory tests for detecting IgM anti-HAV antibody in serum, conducted during 1992–2003 in Manitoba. Results Of 1214 serologically confirmed cases, 534 patients (44%) were shown to be Manitobaʹs aboriginal population. The annual incidence of hepatitis A per 100,000 population decreased significantly during the study period, from 8 in 1992, to 3 in 2003 (p < 0.01). During 1992–1997, incidence per 100,000 population was highest among children aged less than 10 years, ranging from 29.2 in 1992 to 91.3 in 1994. After adjustment, the incidence rate in the northern part of Manitoba was significantly higher than that in the Southern part (p < 0.001, RR, 1.63, 95% CI, 1.10–2.51). Conclusions The differences in incidence rates by age group and health district suggest that vaccination policies may need to be tailored to regional epidemiology. In conjunction with the timely incidence data, sero-surveillance data and risk factor data are essential for informed HAV vaccination and control policies.