Figure 5.

Weekly time series of deaths from all causes (A) and respiratory illness (B) per 10,000 population in Concepción, Chile, 1915–1920 (black lines). Shaded areas highlight 3 periods of high mortality rates associated with 3 waves of the pandemic occurring in July–September 1918, November 1918–March 1919, and August 1919–March 1920. Also shown are the Serfling seasonal regression model baseline (blue lines) and corresponding upper limit of the 95% confidence interval of the baseline (red lines).