Question

A pregnant woman whose niece contracted varicella in the same house was negative for serum antibodies of varicella. What would this mean?

• A. She is susceptible to zoster
• B. She is susceptible to chicken pox
• C. She is immune to chicken pox
• D. She is immune to zoster

Hint:

Absent VZV antibodies indicates no prior exposure, which determines susceptibility to primary infection.

Answer 1

The Correct Option is B

Step 1: Interpret the serology. A negative result for serum varicella-zoster virus (VZV) IgG antibodies means the pregnant woman has no detectable immunity against VZV. She has not previously been infected by chickenpox and has not been vaccinated.

Step 2: Understand VZV serology implications.

• Presence of VZV IgG = past infection or vaccination = immunity to chickenpox and protection against reactivation (zoster is reactivation of latent VZV, so it cannot occur without prior infection).
• Absence of VZV IgG = no prior infection = susceptible to primary varicella (chickenpox).

Step 3: Apply to this scenario. She is seronegative for VZV antibodies and has been exposed to a household contact with active varicella. This means she is susceptible to chickenpox, placing her and her fetus at risk (congenital varicella syndrome if infected in first 20 weeks).

Step 4: Eliminate other options. Zoster occurs only from reactivation of latent VZV; if she has never had chickenpox, she cannot develop zoster. Options C and D are incorrect as she is clearly not immune.

Conclusion: A seronegative pregnant woman exposed to varicella is susceptible to chickenpox.