| Window | Peak | |
|---|---|---|
| Incubation Period | 10-14 dys | 10-12 days (fever onset) |
| Communicable (Infectious) Period | 8 dys (4 days before & after rash ONSET) | Highest just before and during the early rash phase |
| R₀ = basic reproduction number* | 12–18 |
*how many people, on average, an infected person can infect.
| Schedule (ON) | Earliest time | |
|---|---|---|
| Dose 1: MMR | 1 year* | 6 mon. → doesn’t count for school |
| Dose 2: MMRV | 4-6 years | 15 mon.→ count for school |
*If not immune, giving a second dose of vaccine cannot help after the 72 hr PEP window