The reasoning: varicella and mumps
| Feature | Varicella | Mumps |
|---|---|---|
| Agent | VZV (herpesvirus) | Mumps virus (paramyxovirus) |
| Transmission | Airborne, contact with vesicle fluid; SAR ≈ 90% in susceptible household contacts | Droplets, saliva |
| Incubation | 14–16 days (10–21) | 16–18 days (12–25) |
| Communicability | 1–2 days before rash until all lesions crusted (≈ 5 days) | Several days before to 5 days after parotitis |
| Clinical | Pleomorphic, centripetal rash in crops (macule → papule → vesicle → crust), pruritus; mild prodrome in children | Parotitis (often bilateral); ≈ 30% subclinical |
| Complications | Secondary bacterial infection, pneumonia (adults, pregnancy), encephalitis, congenital varicella syndrome (< 20 weeks), neonatal varicella (maternal rash 5 days before to 2 days after delivery), zoster | Orchitis (post‑pubertal males, ≈ 20–30%), oophoritis, aseptic meningitis, pancreatitis, sensorineural deafness |
| Prevention | Live varicella vaccine (not UIP); VZIG for high‑risk exposed (pregnant, immunocompromised, neonates) | MMR (India's UIP uses MR) |