The reasoning: lessons from COVID‑19
| Domain | Lesson |
|---|---|
| Transmission | Predominantly respiratory particles (short‑ and long‑range airborne); pre‑symptomatic and asymptomatic transmission; superspreading (overdispersion, k ≈ 0.1–0.5) driven by crowded, poorly ventilated indoor settings |
| Natural history | Incubation 2–14 days (median ≈ 5; shorter with Omicron); risk of severe disease rises steeply with age and comorbidity |
| Surveillance | ILI/SARI surveillance, lab network expansion (ICMR), genomic surveillance (INSACOG, 2020), wastewater surveillance |
| Non‑pharmaceutical interventions | Test–trace–isolate, quarantine, masks, ventilation, physical distancing; graded restrictions (cost vs benefit) |
| Health system | Medical oxygen (PSA plants, cylinders, concentrators), bed and ICU surge, workforce protection, continuity of essential services (TB, immunisation and ANC fell during lockdowns) |
| Vaccination | Covishield (ChAdOx1), Covaxin (inactivated), Corbevax (protein subunit), ZyCoV‑D (DNA); CoWIN platform; over 220 crore doses; prioritisation by risk |
| Communication | "Infodemic" management; transparent risk communication |
| Equity | Migrant workers, informal sector, digital divide |