Influenza Other Respir Viruses. 2016 Nov 24. doi: 10.1111/irv.12439. [Epub ahead of print]
Severe mortality impact of the 1957 influenza pandemic in Chile.

Chowell G1,2, Simonsen L2,3,4, Fuentes R5, Flores J6,7, Miller MA2, Viboud C2.
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Epidemiological studies of the 1957 influenza pandemic are scarce, particularly from lower income settings.

We analyzed the spatial-temporal mortality patterns of the 1957 influenza pandemic in Chile including detailed age-specific mortality data from a large city and investigated risk factors for severe mortality impact across regions.

Chile exhibited two waves of excess mortality in winter 1957 and 1959 with a cumulative excess mortality rate of 12 per 10,000, and a ~10-fold mortality difference across provinces. High excess-mortality rates were associated with high baseline mortality (R2=41.8%; P=0.02), but not with latitude (P>0.7). Excess mortality rates increased sharply with age. Transmissibility declined from R=1.4-2.1 to R=1.2-1.4 between the two pandemic waves.

The estimated A/H2N2 mortality burden in Chile is the highest on record for this pandemic - about 3-5 times as severe as that experienced in wealthier nations. The global impact of this pandemic may be substantially underestimated from previous studies based on high-income countries. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.


1957 influenza pandemic; Chile; baseline mortality rates; excess mortality rates; latitude; reproduction number; transmissibility

PMID: 27883281 DOI: 10.1111/irv.12439
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