Severe mortality impact of the 1957 influenza pandemic in Chile

Gerardo Chowell, Lone Simonsen, Rodrigo Fuentes, Jose Flores, Mark A. Miller, Cécile Viboud

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Introduction: Epidemiological studies of the 1957 influenza pandemic are scarce, particularly from lower‐income settings.MethodsWe 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.ResultsChile 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=.02), but not with latitude (P>.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.ConclusionsThe estimated A/H2N2 mortality burden in Chile is the highest on record for this pandemic—about three to five 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.
Original languageEnglish
JournalInfluenza and Other Respiratory Viruses
Volume11
Issue number3
Pages (from-to)230-239
Number of pages10
ISSN1750-2640
DOIs
Publication statusPublished - 1 Mar 2017
Externally publishedYes

Keywords

  • 1957 influenza pandemic
  • Chile
  • Baseline mortality rates
  • Excess mortality rates
  • Latitude
  • Reproduction number
  • Transmissibility

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