Volume 15, Number 10—October 2009
Dispatch
Excess Deaths and Immunoprotection during 1918–1920 Influenza Pandemic, Taiwan
Table 1
Excess all-cause deaths of Taiwanese and Japanese persons during 2 influenza epidemic waves in Taiwan, 1918–1920*
Time period | Observed no. deaths | Expected no. deaths† | SD | Excess no. deaths (95% CI) | Excess no. deaths, by wave‡ (95% CI) |
---|---|---|---|---|---|
First wave | |||||
1918 Oct§ | 8,725 | 8,366 | 489 | 359 (0–1,337)¶ | 24,907
(21,426–29,008) |
1918 Nov | 23,156 | 8,042 | 768 | 15,114 (13,578–16,650) | |
1918 Dec |
17,658 |
8,224 |
793 |
9,434 (7,848–11,021) |
|
Second wave | |||||
1919 Dec§ | 9,319 | 8,224 | 793 | 1,095 (0–2,682)¶ | 26,141 (20,572–32,845) |
1920 Jan | 23,906 | 8,478 | 973 | 15,429 (13,482–17,375) | |
1920 Feb | 16,466 | 7,466 | 955 | 9,001 (7,090–10,911) | |
1920 Mar§ | 8,625 | 8,009 | 630 | 616 (0–1,877)¶ |
*CI, confidence interval.
†Expected monthly no. deaths was computed from mean no. deaths for that month during 1916–1922, excluding the epidemic month. Total excess no. deaths for these 2 periods = 51,048 (95% CI 41,998–61,853).
‡Including the excess no. deaths in adjacent months.
§Excess no. deaths for these months are not statistically significant (i.e., not >2 SD above mean).
¶Max (0, lower bound).