The transmission dynamics of Middle East Respiratory Syndrome coronavirus


                  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 (R
                     0), and the model fitting procedure was adopted to calculate the R
                     0 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 R
                     0 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.
               


63
The Middle East respiratory syndrome coronavirus (MERS-CoV), which belongs to the family of 64 coronaviruses like the novel coronavirus, was first detected in a hospital in Jordan in April 2012. It caused two

Data collection and processing
Further, until the data collection deadline (18 December 2019) for this study, countries in the Middle East 100 continued to report sporadic confirmed MERS-CoV cases monthly to WHO during the COVID-19 pandemic. By 101 comparing this data with the publicly available information reported by the Ministries of the two countries Patient data, including gender, age, region, comorbidities, occupation, e.g., health care worker (HCW), 105 severity of disease, date of death, date of laboratory confirmation, date of symptom onset, and contact history,

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were also retrieved and used as input data for the models. Furthermore, according to the MERS epidemic report

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[13] published on 18 December 2019: 8 two cases were reported on 11 October 2015 and 28 August 2018. However, both were imported cases and did 111 not cause a large-scale epidemic. Therefore, they were excluded from the study.

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(2) Overall, 1,469 MERS cases with detailed data were recorded in Saudi Arabia. This included five 113 patients with mild symptoms, 73 asymptomatic patients, 66 cases were reported as "'Not Available (NA)', 37 114 cases recorded as 'No Report (NR)', and three cases with blurred information. Therefore, 1,285 cases, with a 115 valid 'date of symptom onset', were included in the Saudi Arabia database.      d) The proportion of the symptomatic population was p (0 ≤ p ≤1), and the incubation and latent 156 periods were 1/ω1 and 1/ω2, respectively. Therefore, after the incubation period, the E population could The definitions of the parameters in the SEIARD model are shown in Table 3, and the equations in the 162 SEIARD model were as follows:

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For each outbreak, the basic reproduction number (R0) was used to determine the transmissibility of 218 MERS-CoV. R0 is one of the key values that is used predict whether an infectious disease will spread in a 219 population or die out [29]. When R0 < 1, the disease will not amount to an epidemic, but will gradually disappear, 220 with the number of infected persons decreasing monotonically to zero. Conversely, when R0 > 1, the disease will 221 become an epidemic. For the SEIARD model, R0 was calculated according to the following equation:

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MERS is a kind of respiratory infectious disease that is characterised by seasonality and periodicity.

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However, its transmission route is complicated and unknown, and moreover, in some cases, it is asymptomatic.

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Reportedly, identifying the natural host of emerging human-infected pathogens is the first step in preventing

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Weekly data on disease incidence were used to calculate the infectivity coefficient of the virus, , as well as its 409 basic reproduction number, R0. Thus, it was observed that the models could better simulate the MERS epidemic,

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All relevant data are within the paper and its Supporting Information files. 424 https://wwwwhoint/en/news-room/factsheets/detail/mi-ddle-east-respiratory-syndrome-coronavirus-(mers-cov).            Note: (1) One of the two cases in Germany was reported by The Robert Koch Institute, so it was included in 3 J o u r n a l P r e -p r o o f