Hepatitis B virus (HBV) and tuberculosis have much in common. Approximately one-third of the world has been infected with each, and in the world of rheumatology, both represent important causes of infectious morbidity in patients who use biological and other immunosuppressive therapies. Furthermore, unlike most infections encountered in the biological setting, reactivation or progression of both hepatitis B and latent tuberculosis infection is largely preventable. Both infections can be screened for and preventive therapy is available and efficacious when employed correctly. Perhaps most pertinent to this editorial, the similarities do not end there. As for tuberculosis, there is variation in rheumatological practice and sometimes confusion, with optimal screening strategies often obscured by the fog of inadequate data and imperfect tests. The publication by Lan et al1 (pp. 1719) in this edition of Annals of Rheumatic Diseases helps clear the fog, adds important insights into the screening question, and provides strong data to suggest an optimal algorithm for HBV screening in this setting.

HBV is a DNA virus highly endemic in southeast Asia, Africa and other regions of the world outside of North America and western Europe, whereby most infection is transmitted perinatally (figure 1).2 If overlaid with the map for tuberculosis prevalence, one would be hard-pressed to distinguish the two. Within low prevalence regions, and also similar to tuberculosis, infection is more common among certain subgroups such as persons with HIV, a history of intravenous drug use, or a history of incarceration (box 1). In a substantial majority of HBV-infected patients, generally those infected perinatally, infection is chronic and life-long, frequently resulting in cirrhosis and eventually death.2 The lifetime risk of death among men from endemic regions with HBV approaches 40%, with substantial risk among women noted although several fold lower.3 Worldwide, approximately one million …