Situation: A 31-year-old man was diagnosed with human immunodeficiency virus (HIV) infection and chronic hepatitis B at the same visit. He is enrolled at a treatment hub and starts one tablet of tenofovir–lamivudine–dolutegravir once daily. He works rotating day and night shifts at a call center and lives with his female partner, whose hepatitis B status is unknown. His partner is tested. Her results are: hepatitis B surface antigen (HBsAg) negative; antibody to hepatitis B surface antigen (anti-HBs) negative; antibody to hepatitis B core antigen (anti-HBc) negative. Which instruction should the nurse give the couple?

Interpretation of the partner’s serology

The partner’s results show HBsAg negative, anti-HBs negative, and anti-HBc negative. This triple-negative pattern means she has no current hepatitis B infection, no evidence of past infection, and no vaccine-induced immunity. She is therefore considered susceptible to hepatitis B virus (HBV). In contrast, immunity would be demonstrated by a positive anti-HBs result, which is absent here.

Because she is a sexual and household contact of a person with chronic hepatitis B, the priority is to initiate the hepatitis B vaccine series immediately. Until the series is completed and immunity is confirmed by a positive anti-HBs titer, barrier protection with condoms is needed to reduce sexual transmission risk. The vaccine series is the core preventive measure; condoms are a temporary adjunct during the window before immunity develops.

Watch out! Option 2 is incorrect because negative anti-HBs does not indicate immunity. Option 3 is incorrect because an undetectable HIV viral load prevents sexual transmission of HIV only, not hepatitis B. Option 4 is incorrect because hepatitis B is not spread through shared dishes or cups; transmission occurs through blood, semen, and other body fluids, so the focus should be on vaccination and safe sexual practices rather than separating utensils.

The triple-negative profile defines a susceptible person who requires vaccination. This aligns with postexposure and preventive guidance for susceptible contacts of individuals with chronic HBV infection. In occupational and household exposure settings, hepatitis B vaccination is the standard intervention for unvaccinated susceptible persons ^[3].

Sexual transmission of HBV is a well-recognized route, and studies of high-risk populations confirm that HBV serologic markers are common among individuals with HIV or high-risk sexual behavior ^[1][2]. Coinfection with HIV and HBV is clinically significant, but the partner’s immediate risk is from HBV exposure, not from the partner’s HIV status. The instruction to use condoms until immunity is confirmed addresses the sexual transmission route specifically.

Key point! Hepatitis B vaccine series plus condom use until anti-HBs is confirmed positive is the correct dual strategy for a susceptible sexual partner of a person with chronic hepatitis B.