2015 Middle East Respiratory Syndrome Coronavirus (MERS-CoV) nosocomial outbreak in South Korea: insights from modeling

Abstract

Background. Since the emergence of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in 2012, more than 1,300 laboratory confirmed cases of MERS-CoV infections have been reported in Asia, North Africa, and Europe by July 2015. The recent MERS-CoV nosocomial outbreak in South Korea quickly became the second largest such outbreak with 186 total cases and 36 deaths in a little more than one month, second only to Saudi Arabia in country-specific number of reported cases.Methods. We use a simple mathematical model, the Richards model, to trace the temporal course of the South Korea MERS-CoV outbreak. We pinpoint its outbreak turning point and its transmissibility via basic reproduction number R0 in order to ascertain the occurrence of this nosocomial outbreak and how it was quickly brought under control.Results. The estimated outbreak turning point of ti = 23.3 days (95% CI [22.6–24.0]), or 23–24 days after the onset date of the index case on May 11, pinpoints June 3–4 as the time of the turning point or the peak incidence for this outbreak by onset date. R0 is estimated to range between 7.0 and 19.3.Discussion and Conclusion. The turning point of the South Korea MERS-CoV outbreak occurred around May 27–29, when control measures were quickly implemented after laboratory confirmation of the first cluster of nosocomial infections by the index patient. Furthermore, transmissibility of MERS-CoV in the South Korea outbreak was significantly higher than those reported from past MERS-CoV outbreaks in the Middle East, which is attributable to the nosocomial nature of this outbreak. Our estimate of R0 for the South Korea MERS-CoV nosocomial outbreak further highlights the importance and the risk involved in cluster infections and superspreading events in crowded settings such as hospitals. Similar to the 2003 SARS epidemic, outbreaks of infectious diseases with low community transmissibility like MERS-CoV could still occur initially with large clusters of nosocomial infections, but can be quickly and effectively controlled with timely intervention measures.

Estimating and modelling the transmissibility of Middle East Respiratory Syndrome CoronaVirus during the 2015 outbreak in the Republic of Korea

“…This suggests that the effectively breaking point took place on 28th or 29th May. This is in agreement with the result of Hsieh who fitted the Richards model to cumulative case data. Transmission dynamics modelling suggests the reproductive number before the intervention ( R 0 ) has median 9.11 and 95% CI [5.32, 15.92] with the breaking point at 28th May (or 6.85 [4.13, 11.92] if the breaking point is at 29th May) for the model assuming both contact rate and diagnosis rate vary with the breaking point (Table and Table C1 in Appendix ).…”

“…For the model that assumes only contact rate varies with the breaking point, the estimates of R 0 are: 6.07 [4.20, 8.70] (5.36 [3.76, 7.60]) (see Tables C2 and C3 in Appendix ). These estimates are compatible with the previous studies . Although all used cumulative data while we use daily incidence data, the similar estimates were obtained.…”

“…It has been the largest outbreak outside of the Middle East so far, and much theoretical attention has been attracted to estimate its transmissibility. Hsieh used a phenomenological model to obtain an estimate of R 0 ranging from 7.0 to 19.3. Xia et al .…”

Temporal patterns and geographic heterogeneity of Zika virus (ZIKV) outbreaks in French Polynesia and Central America

“…While the Richards model has many advantages in its ease of use and minimum requirement for the data needed for implementation (Hsieh, Fisman & Wu, 2010), its use of cumulative case number both could smooth out stochastic variations in disease incidence data but also introduces auto-correlation in the data, potentially leading to biased high estimates of R 0 as well as errors in parameter estimates and subsequently underestimation of uncertainty in the corresponding confidence intervals (Razum et al, 2003; King et al, 2015; Hsieh, 2015). …”

Co‐localization of Middle East respiratory syndrome coronavirus ( MERS ‐CoV) and dipeptidyl peptidase‐4 in the respiratory tract and lymphoid tissues of pigs and llamas

“…Since then, as per September 2018, 2,249 laboratory‐confirmed cases and at least 798 associated deaths have been reported to the World Health Organization (World Health Organization (WHO), ). Although the majority of cases were reported in the Middle East region, travel‐associated cases have been documented in other parts of the world (Cotten, Watson, et al., 2013; Hsieh, ; Tsiodras et al., ; WHO, ). On September 8th, 2018, South Korea reported the first MERS‐CoV case since the end of an outbreak in 2015, suggesting that MERS‐CoV is still a worldwide threat (WHO, ).…”