Annual trends of hepatitis C virus infection in Manitoba between 1998 and 2018: A focus on special populations.

Background: Hepatitis C virus (HCV) infection is a major cause of liver-related morbidity and mortality worldwide. Epidemiological data of HCV infection in the Canadian province of Manitoba are limited. Methods: A population-based retrospective study was conducted using data from the Manitoba Centre for Health Policy repository. Using the test results provided by the Cadham provincial laboratory, individuals in Manitoba with a diagnosis of HCV infection were identified. Annual prevalence and incidence rates (crude and standardized) were calculated for the overall population and stratified by sex, regional health authority (RHA), residence area, income quintile, and special population groups (children, older adults, and pregnant persons). Results: A total of 8,721 HCV cases were diagnosed between 1998 and 2018 in Manitoba. Overall crude HCV incidence and prevalence were estimated as 0.03% and 0.37% during the study period, respectively. No significant change was observed in the standardized HCV incidence rate (per 100,000) during the study period (54.3 in 1998 and 54.8 in 2018). However, the standardized HCV prevalence (per 100,000) increased from 52.5 (95% CI 39.2-68.7) in 1998 to 655.2 (95% CI 605.9-707.3) in 2018. An overall average incidence rate based on sex, RHA, region, income, and special population groups was observed to be higher in males (40.1), Winnipeg RHA (42.7), urban region (42.3), low-income quintiles (78.5), and pregnant persons (94.3), respectively. Conclusion: Although incidence rates of HCV infection in Manitoba appeared to have initially declined, rates showed an upward trend by the end of the study period while prevalence increased steadily.