Travel Med Infect Dis

. 2021 Dec 22;102243.
doi: 10.1016/j.tmaid.2021.102243. Online ahead of print.
The transmission dynamics of Middle East Respiratory Syndrome coronavirus

Jia Rui 1 , Qiupeng Wang 2 , Jinlong Lv 3 , Bin Zhao 4 , Qingqing Hu 5 , Heng Du 6 , Wenfeng Gong 7 , Zeyu Zhao 1 , Jingwen Xu 1 , Yuanzhao Zhu 1 , Xingchun Liu 1 , Yao Wang 1 , Meng Yang 1 , Li Luo 1 , Qiuping Chen 8 , Benhua Zhao 1 , Yanhua Su 9 , Jing-An Cui 10 , Tianmu Chen 11



Background: In this study, we aimed to quantify the contribution of different transmission routes of the Middle East respiratory syndrome (MERS) and determine its transmissibility.
Methods: Based on the natural history and transmission features of MERS in different countries, a susceptible-exposed-symptomatic-asymptomatic-recovered/death (SEIARD) model and a multi-route dynamic model (MMDM). The SEIARD model and MMDM were adopted to simulate MERS in South Korea and Saudi Arabia, respectively. Data on reported MERS cases in the two countries were obtained from the World Health Organization. Thereafter, the next generation matrix method was employed to derive the equation for the basic reproduction number (R0), and the model fitting procedure was adopted to calculate the R0 values corresponding to these different countries.
Results: In South Korea, 'Person-to-Person' transmission was identified as the main mode of MERS transmission in healthcare settings, while in Saudi Arabia, in addition to 'Person-to-Person' transmission, 'Host-to-Host' and 'Host-to-Person' transmission also occurred under certain scenarios, with camels being the main host. Further, the fitting results showed that the SEIARD model and MMDM fitted the data well. The mean R0 value was 8.59 (95% confidence interval [CI]: 0-28.02) for MERS in South Korea, and for MERS in Saudi Arabia, it was 1.15 and 1.02 (95% CI: 0.86-1.44) for the 'Person-to-Person' and 'Camel-to-Camel' transmission routes, respectively.
Conclusions: The SEIARD and MMDM model can be used to simulate the transmission of MERS in different countries. Additionally, in Saudi Arabia, the transmissibility of MERS was almost the same among hosts (camels) and humans.

Keywords: Basic reproduction number; Coronavirus; Mathematical model; Middle East respiratory syndrome.