Incubation Period
Chickenpox (varicella) has an incubation period of 10 to 21 days, most commonly 14–16 days. This is the time between exposure to the varicella-zoster virus (VZV) and the onset of symptoms.
What Happens During Incubation
- The virus enters through the respiratory mucosa or conjunctiva.
- It replicates locally, then spreads via the bloodstream (viremia) to the skin and other organs.
- The characteristic rash appears once the immune response triggers inflammation in infected skin cells.
Contagious Period
Infected individuals are contagious from 1–2 days before the rash appears until all lesions have crusted over (usually 5–7 days after rash onset).
Clinical Implications
- If exposed and non-immune, monitor for symptoms for 21 days.
- Post-exposure prophylaxis (varicella vaccine or varicella-zoster immune globulin) may be recommended for high-risk individuals (pregnant, immunocompromised, newborns) within a specific window.
