American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What condition indicates a child is not immune and requires vaccination against a specific virus?

1. HBsAg +, HBsAb -, HBcAb -

2. HBsAg -, HBsAb -, HBcAb -

3. HBsAg -, HBsAb +, HBcAb +

4. HBsAg -, HBsAb +, HBcAb -

The correct answer is: HBsAg -, HBsAb -, HBcAb -

The scenario where a child has HBsAg negative, HBsAb negative, and HBcAb negative indicates that the child has no evidence of past or current hepatitis B virus infection. This serological profile means that the child is entirely susceptible to hepatitis B, signifying that they have not been exposed to the virus. Consequently, vaccination against the hepatitis B virus is necessary to provide immunity. In detail, HBsAg is a marker for active infection; the absence of this marker indicates that there is no active hepatitis B infection. The absence of HBsAb (antibody to the hepatitis B surface antigen) means that the child has not developed immunity in response to either infection or vaccination. Furthermore, the absence of HBcAb indicates that there has been no exposure to the hepatitis B virus. Therefore, this child's complete lack of any hepatitis B markers necessitates vaccination to establish immunity against the virus. Other profiles present variations of either previous exposure or existing immunity, negating the requirement for vaccination. For instance, the presence of HBsAb without HBsAg implies that the individual is immune, either through past infection or vaccination, and does not require further vaccination. Hence, the combination found in the correct answer is definitive for initiating the vaccination process.