Breakthrough of hepatitis B virus escape mutants after vaccination and virus reactivation

Escape mutants of hepatitis B virus (HBV) carry mutations in the major antigenic region of the hepatitis B surface antigen (HBsAg). They are able to grow in the presence of antibodies against HBsAg (anti-HBs) and may escape detection by immuno assays for HBsAg. Antibodies against HBV core antigen (anti-HBc) are considered to be a universal marker for active or resolved HBV infections but they may appear very late. Highly sensitive detection of HBV DNA is the most universal reliable marker of infectivity, but in the blood donation setting even the most sensitive assay for HBV DNA may not detect all infectious donations. This brief report describes three cases of HBV infections caused by HBV escape mutants. The implications of the findings for the prevention of HBV transmission through donor blood are discussed.