What is the commonly cited incubation period for varicella after exposure?

• A. 7 days
• B. 14 days
• C. 21 days
• D. 28 days

Answer: (C)

Varicella incubation is the time from exposure to the onset of the rash. For chickenpox, the rash typically appears around two weeks after exposure, but the overall window can extend up to about three weeks. In practice, the maximum incubation period used for exposure assessment and quarantine guidance is 21 days, which is why this duration is commonly cited. Seven days would usually be too short for the rash to develop, fourteen days is within the usual window but does not reflect the commonly cited maximum, and twenty-eight days exceeds the known upper range. So 21 days best captures the standard upper bound used in guidance and exams.