Which of the following statements best reflects HAV serology indicating immunity rather than active infection?

• A. IgM anti-HAV positive
• B. IgG anti-HAV positive
• C. Both IgM and IgG anti-HAV positive
• D. IgG anti-HAV negative

Answer: (B)

Immunity to hepatitis A is reflected by IgG anti-HAV antibodies. IgG anti-HAV persists long after exposure or vaccination and provides lasting protection, so its presence indicates immunity. In contrast, IgM anti-HAV appears early in active or recent infection, signaling current disease rather than lasting immunity. Therefore, a pattern with IgG anti-HAV positive and IgM anti-HAV negative best reflects immunity without active infection. If IgM were positive, that would point to an acute infection; IgG negative would indicate no immunity. If both IgM and IgG are present, you may be in a transition period, but IgG positivity alone is the hallmark of immunity.