True or false: HBV infections:

TRUE:

B. May not be clinically recognized but may lead to chronic hepatitis.

C. Reliably protect against subsequent HBV infection regardless of the measured antibody titer to hepatitis B surface antigen (HBsAg).

FALSE

A. Are usually asymptomatic

D. Are completely prevented by postexposure administration of HBIg hepatitis B immunoglobulin (HBIg).

E. Preclude subsequent infection with HDV.

DISCUSSION: Although some types of hepatitis are more often asymptomatic than symptomatic, that is not the case for hepatitis B. Further, even if the HBV infection is asymptomatic, serious long-term side effects may occur. A prior infection with hepatitis B confers lifelong immunity even if the antibody titer wanes below the protective level of 10 mIU. HBIg is useful in reducing the incidence of postexposure HBV infection from around 30% with no intervention, to 15% with standard immune globulin, to about 5% to 7% with HBIg. HBV infection is required for infection with HDV and is therefore an essential step toward, rather than preventive of, HBV infection.