Estimating the risk of Middle East respiratory syndrome (MERS) death during the course of the outbreak in the Republic of Korea, 2015

Kenji Mizumoto, Masaya Saitoh, Gerardo Chowell, Yuichiro Miyamatsu, Hiroshi Nishiura

Research output: Contribution to journalArticle

21 Scopus citations


Objectives: A large cluster of the Middle East respiratory syndrome (MERS) linked to healthcare setting occurred from May to July 2015 in the Republic of Korea. The present study aimed to estimate the case fatality ratio (CFR) by appropriately taking into account the time delay from illness onset to death. We then compare our estimate against previously published values of the CFR for MERS, i.e., 20% and 40%. Methods: Dates of illness onset and death of the MERS outbreak in the Republic of Korea were extracted from secondary data sources. Using the known distribution of time from illness onset to death and an integral equation model, we estimated the delay-adjusted risk of MERS death for the South Korean cluster. Results: Our most up-to-date estimate of CFR for the MERS outbreak in South Korea was estimated at 20.0% (95% confidence intervals (CI): 14.6, 26.2). During the course of the outbreak, estimate of the CFR in real time appeared to have decreased and become significantly lower than 40%. Conclusions: The risk of MERS death in Korea was consistent with published CFR. The estimate decreased with time perhaps due to time-dependent increase in case ascertainment. Crude ratio of cumulative deaths to cases underestimates the actual risk of MERS death because of time delay from illness onset to death.

Original languageEnglish (US)
Pages (from-to)7-9
Number of pages3
JournalInternational Journal of Infectious Diseases
StatePublished - Oct 1 2015



  • Case fatality ratio
  • Epidemic
  • Korea
  • MERS
  • Statistical estimation

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases

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