# Situation: A 29-year-old woman has a pre-employment medical examination at a private manufacturing company. Her hepatitis B surface antigen (HBsAg) test is positive. Her alanine aminotransferase (ALT) level is normal, she has no symptoms, and she recalls no past illness with jaundice. The occupational health nurse counsels her. Her family is screened at the Rural Health Unit (RHU). The results for HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) are: Mother: HBsAg negative, anti-HBs positive, anti-HBc positive Husband: HBsAg negative, anti-HBs negative, anti-HBc negative Sister: HBsAg positive, anti-HBs negative, anti-HBc positive Brother: HBsAg negative, anti-HBs positive, anti-HBc negative Which family member should the nurse refer for hepatitis B vaccination?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629718  
> language: ko  
> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 29-year-old woman has a pre-employment medical examination at a private manufacturing company. Her hepatitis B surface antigen (HBsAg) test is positive. Her alanine aminotransferase (ALT) level is normal, she has no symptoms, and she recalls no past illness with jaundice. The occupational health nurse counsels her.

Her family is screened at the Rural Health Unit (RHU). The results for HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) are:
Mother: HBsAg negative, anti-HBs positive, anti-HBc positive
Husband: HBsAg negative, anti-HBs negative, anti-HBc negative
Sister: HBsAg positive, anti-HBs negative, anti-HBc positive
Brother: HBsAg negative, anti-HBs positive, anti-HBc negative
Which family member should the nurse refer for hepatitis B vaccination?

## 보기

1. The mother
2. The brother
3. The husband **✔ 정답**
4. The sister

**정답: 3**

## 해설

A person with all three markers negative has never been infected and is not immune, so the husband needs the vaccine. Anti-HBs with anti-HBc (mother) means immunity after a resolved infection, and anti-HBs alone (brother) means immunity from vaccination. A positive HBsAg (sister) means current infection; vaccination cannot help her, and she needs medical evaluation instead.

## 심화 해설

Interpretation of hepatitis B serologic markers

A positive HBsAg indicates the presence of hepatitis B surface antigen, which means the person currently harbors the virus. In contrast, anti-HBs is the protective antibody; its presence signals immunity, whether from resolved infection or from vaccination. The anti-HBc (core antibody) is a marker of exposure to the actual virus, not of protection, and it appears only after natural infection, never after vaccination alone.

The four family members can be classified by combining these three markers. The husband is negative for HBsAg, anti-HBs, and anti-HBc, which means he has never been exposed to hepatitis B and has no immunity. He is susceptible and is the correct candidate for vaccination.

| Family member | HBsAg | Anti-HBs | Anti-HBc | Interpretation | Action |
| --- | --- | --- | --- | --- | --- |
| Mother | Negative | Positive | Positive | Resolved past infection with natural immunity | No vaccine needed |
| Husband | Negative | Negative | Negative | Susceptible, never infected, not immune | Refer for hepatitis B vaccination |
| Sister | Positive | Negative | Positive | Current or chronic HBV infection | Medical evaluation, not vaccination |
| Brother | Negative | Positive | Negative | Immunity from prior vaccination | No vaccine needed |

Key point! The presence of anti-HBc distinguishes immunity from natural infection from immunity from vaccination. The mother has both anti-HBs and anti-HBc, indicating she was infected in the past and cleared the virus. The brother has anti-HBs but no anti-HBc, which is the classic profile of vaccine-induced immunity. Neither requires vaccination.

Watch out! The sister has a positive HBsAg, which means she is currently infected. Vaccination is ineffective once infection is established; instead, she needs further evaluation for chronic hepatitis B, including liver function tests, hepatitis B e antigen (HBeAg) status, and HBV DNA levels to assess disease activity and infectivity.

For the index patient, the 29-year-old woman with positive HBsAg and normal ALT, the occupational health nurse should recognize that she may be a chronic carrier. Normal ALT and absence of symptoms do not rule out chronic infection. She should be counseled about transmission prevention, the importance of regular monitoring, and the need for family members to be screened and vaccinated if susceptible. The serologic screening of her family at the RHU is a key public health measure, because household contacts of a chronic carrier have a significant risk of acquiring HBV through percutaneous or mucosal exposure to infected blood or body fluids.

Interpreting hepatitis B serology requires looking at all three markers together, not any single result in isolation. A negative HBsAg alone does not confirm immunity, and a positive anti-HBc alone does not mean the person is protected. The husband’s triple-negative profile is the only one that indicates susceptibility and therefore the only one that warrants referral for vaccination.

## 임상 시나리오

Hepatitis B Serologic Interpretation and Vaccination ReferralIdentifying the susceptible contact in family screening
A person with all three markers negative (HBsAg negative, anti-HBs negative, anti-HBc negative) has never been infected and has no immunity. This is the susceptible profile that requires hepatitis B vaccination.

Anti-HBs positive with anti-HBc positive indicates immunity from a resolved natural infection, as seen in the mother. Anti-HBs positive with anti-HBc negative indicates vaccine-induced immunity, as seen in the brother. Neither requires vaccination.

A positive HBsAg means current or chronic infection. The sister with this result should be referred for medical evaluation, not vaccination, because the vaccine cannot clear an existing infection.

CautionDo not confuse anti-HBc with protection. It is a marker of natural exposure only and never appears after vaccination alone. Always interpret the full three-marker panel before deciding on vaccination.

## 핵심 개념

- **HBsAg** — Hepatitis B surface antigen; positive result indicates current HBV infection or carrier state.
- **anti-HBs** — Antibody to hepatitis B surface antigen; presence indicates immunity from resolved infection or vaccination.
- **anti-HBc** — Antibody to hepatitis B core antigen; appears only after natural infection, not after vaccination.
- **susceptible** — Negative for HBsAg, anti-HBs, and anti-HBc; never infected and not immune, requires vaccination.
- **vaccine-induced immunity** — Profile of anti-HBs positive with anti-HBc negative, indicating protection from hepatitis B vaccination.

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