Identification of acute vaccine-preventable hepatitis in individuals with chronic hepatitis in British Columbia between 1991 and 2007

BACKGROUND:

In British Columbia (BC), hepatitis A virus (HAV) and hepatitis B virus (HBV) vaccines are provincially funded for persons with chronic hepatitis infections.

PURPOSE:

To assess the effectiveness of BC public health follow-up of HBV and hepatitis C virus (HCV) cases and immunization policy by determining the number of vaccine-preventable acute hepatitis infections reported following a chronic HBV or HCV diagnosis, by examining demographic characteristics and by observing temporal trends.

METHODS:

All newly identified cases of HAV, HBV and HCV between 1991 and October 2007 were extracted from the BC integrated Public Health Information System and linked to ascertain cases of hepatitis suprainfection.

RESULTS:

Between 1991 and October 2007, 30 BC residents with chronic HBV and 104 with HCV were subsequently diagnosed with HAV. Acute HBV was identified in 162 persons previously diagnosed with HCV. Significantly more men than women developed hepatitis suprainfection (P<0.0001), but women were of a younger age when they were diagnosed with HAV (P=0.02) and acute HBV (P=0.0002). HAV suprainfection cases among those with HCV peaked in 1998 at 33 cases and declined to zero cases in 2007. In comparison, HBV suprainfection among individuals with chronic HCV peaked in 1996 at 26 cases and declined to two cases in 2007.

DISCUSSION:

Cases of HAV and acute HBV have declined among HCV-infected individuals. However, despite the availability of publicly funded vaccines for high-risk groups, a substantial number of acute HBV infections post-HCV identification are still identified, indicating that follow-up and vaccination coverage should be improved in these populations.