Serial intervals, probability of infection, R0 and R for measles infections on the ships ‘America’, ‘Garrow’ and ‘Roslin Castle’ travelling from England to Australia, 1838–1882
| Serial interval | |||||||
|---|---|---|---|---|---|---|---|
| Ship | Generation | Days into voyage | Measles cases | Mean (95% CI) | Probability of infection | Basic reproductive number (R0) (outbreak) | Effective reproductive number (R) (outbreak) |
| America* | 1 | 24–27 | 3 | 0.34 | – | – | |
| 2 | 43 | 1 | 17 (12.7 to 21.3) | 0.13 | – | – | |
| 3 | 54 | 1 | 11 | 0.13 | – | – | |
| 4 | 65 | 1 | 11 | 0.13 | – | – | |
| Garrow | 1 | 11–14 | 3 | – | 0.22 | 7.1 | 1.3 |
| 2 | 22–28 | 8 | 12 (11.2 to 13.1) | 0.22 | – | – | |
| 3 | 35–41 | 25 | 13 (12.7 to 13.5) | 0.54 | – | – | |
| 4 | 45–49 | 27 | 10 (9.3–10.0) | 0.2 | – | – | |
| Roslin Castle | 1 | 4–9 | 2 | – | 0.05 | 10.9 | 1.6 |
| 2 | 14–24 | 21 | 11 (10.3–12.5) | 0.47 | – | – | |
| 3 | 28–36 | 29 | 13 (13.0–13.6) | 0.59 | – | – | |
| Combined voyages | 3–4 | – | 101 | 12.3 (12.1–12.5) | – | – | – |
*The convict ship ‘America’ continued to take prisoners on board until day 27 of the voyage. The first three measles cases were put ashore at Woolwich, England on day 27.