Epidemiological evidence of an early wave of the 1918 influenza pandemic in New York City - PubMed (original) (raw)

Epidemiological evidence of an early wave of the 1918 influenza pandemic in New York City

Donald R Olson et al. Proc Natl Acad Sci U S A. 2005.

Abstract

The 1918 "Spanish flu" was the fastest spreading and most deadly influenza pandemic in recorded history. Hypotheses of its origin have been based on a limited collection of case and outbreak reports from before its recognized European emergence in the summer of 1918. These anecdotal accounts, however, remain insufficient for determining the early diffusion and impact of the pandemic virus. Using routinely collected monthly age-stratified mortality data, we show that an unmistakable shift in the age distribution of epidemic deaths occurred during the 1917/1918 influenza season in New York City. The timing, magnitude, and age distribution of this mortality shift provide strong evidence that an early wave of the pandemic virus was present in New York City during February-April 1918.

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Figures

Fig. 1.

Fig. 1.

All-cause and P&I monthly mortality rates for all ages (A and B) and all-cause mortality rates by age group (_C_-H) are calculated per 10,000 population. Observed rates are days-per-month adjusted. Expected model baselines (solid lines) are derived from each series of nonepidemic months. Epidemic thresholds (dashed lines) are the upper 95% confidence limit above each baseline. The major epidemic influenza season months are indicated (shaded). Two 1917/1918 influenza season peaks (arrowheads) show excess mortality primarily confined to the ≥65-years age group in January (C), and to the groups <45 years old in March 1918 (_E_-H). Other severe mortality events are evident: summer diarrheal disease epidemics were confined to young children (H), the 1916 polio epidemic to all children (G and H), and the summer 1917 heat wave and diarrheal disease epidemic among the youngest and oldest age groups (C and H).

Fig. 2.

Fig. 2.

Annual and epidemic period mortality rates by age group. (A) Average age-specific calendar year P&I death rates are plotted in a U-shaped age distribution for 1915-1917 (○), and in the characteristic W-shaped distribution for the pandemic year 1918 (▪). (B) Influenza-season-attributable excess deaths are plotted for the 1915/1916 epidemic influenza season (○), the epidemic months March and April 1918 (▴), and the pandemic season from September 1918 through April 1919 (▪). (C) The excess rates are plotted on a log10 scale. (D) Relative risk of death is plotted by age group on a log10 scale for the March and April 1918 epidemic period (▴) and the pandemic from September 1918 through April 1919 (▪) relative to the severe 1915/1916 epidemic season.

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References

    1. Glezen, W. P. (1996) Epidemiol. Rev. 18, 64-76. - PubMed
    1. Johnson, N. P. A. S. & Müller, J. (2002) Bull. Hist. Med. 76, 105-115. - PubMed
    1. Reid, A. H. & Taubenberger, J. K. (2003) J. Gen. Virol. 84, 2285-2292. - PubMed
    1. Jordan, E. O. (1927) Epidemic Influenza: A Survey (Am. Med. Assoc., Chicago).
    1. Taubenberger, J. K., Reid, A. H., Krafft, A. E., Bijwaard, K. E. & Fanning, T. G. (1997) Science 275, 1793-1796. - PubMed

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