Table 1. Relative excess pulmonary tuberculosis (PTB) mortality due to influenza, pneumonia, and combined diagnosis of influenza/pneumonia during the Russian (1889) and Spanish (1918) influenza pandemics.
| Increase in PTB mortality due to: | City of Bern | Switzerland | ||||
|---|---|---|---|---|---|---|
| Increase by a factor of n per 100 deaths1 | 95% CI | p-value | Increase by a factor of n per 100 deaths1 | 95% CI | p-value | |
| Russian influenza pandemic | ||||||
| Influenza | 1.5 | 1.4–1.6 | <0.001 | 2.00 | 1.8–2.2 | <0.001 |
| Pneumonia | 1.5 | 0.9–2.3 | 0.12 | 2.4 | 2.1–2.7 | <0.001 |
| Influenza and pneumonia | 1.4 | 1.1–1.8 | 0.005 | 1.50 | 1.4–1.6 | <0.001 |
| Spanish influenza pandemic | ||||||
| Influenza | 3.6 | 0.7–18.0 | 0.13 | 1.5 | 1.1–1.8 | 0.004 |
| Pneumonia | 36.4 | 1–1272.5 | 0.048 | 6.9 | 2.8–17.3 | <0.001 |
| Influenza and pneumonia | 4.1 | 1.1–15.6 | 0.037 | 1.7 | 1.3–2.2 | <0.001 |
PTB, pulmonary tuberculosis; 95% Cl, 95% confidence interval
1 per 100,000 population
Estimates based on the time periods between 01.01.1889 to 31.12.1894 (Russian influenza pandemic) and 01.01.1918 to 31.12.1920 (Spanish influenza pandemic)