COVID-19? When will the peak and the end to this pandemic occur? Answers to 1 these questions are essential for implementing the policies needed, especially in the 2 economic and healthcare sectors. The whole world is affected, and many have lost 3 their lives; hospitals are packed, healthcare providers are overwhelmed, and 4 businesses are closed. 5 The pathogen of SARS-CoV-2 has the same phylogenetic similarity to SARS-CoV 6
and MERS-CoV. Coronavirus can infect humans and some wild animals such as bats, 7 birds, and mice. These viruses affect the major systems in the body which are 8 respiratory, gastrointestinal, hepatic, and central nervous system. The outbreak of 9 coronaviruses demonstrated evidence of animal-to-human transmission and human- 10 to-human transmission. The vaccines and appropriate treatment are needed to stop the 11 COVID-19 pandemic and any upcoming coronavirus outbreaks in the future. As long 12
as there is direct contact between humans and animals, and the changes of the climate 13 and ecology, there is still a possibility that another pandemic may occur (Chen, 2020) . 14 Saudi Arabia is one of many countries suffering from COVID-19. This will lead to 15 negative impacts in many sectors. Saudi Arabia is a premier economic power, not 16 only because it is the leading country in oil production, but also because it is 17 considered the heart of the Islamic countries. to forecast the spread of diseases, and they were successful. SIR model is one of the 48 All rights reserved. No reuse allowed without permission.
was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. . https://doi.org/10.1101/2020.05.05.20091520 doi: medRxiv preprint most common models that could forecast the end point of COVID-19 in Saudi Arabia 1 (Bailey, 1975 ). 2
Susceptible, Infected, and Recovered (SIR) is a commonly used model that tracks the 3 process of a certain disease. SIR is used to estimate vital epidemiological parameters, 4 such as forecasting works and transmission rates (Ming, 2020). Since some people are 5
asymptomatic, it is difficult to trace this virus and to determine the first case in Saudi 6
Arabia. Moreover, the uncertainty of determining the exact number of infected people 7
is due to some of them being infected but either asymptomatic or have mild 8 symptoms, such as a common cold, will be a problem too. It is interesting to use a 9 mathematical procedure that has dealt with diseases, such as COVID-19, and apply it 10
to have an evidence basis for forecasting. 11
Method 12
Based on the nature of COVID-19 and the characteristics of the virus, SARS-CoV-2 13 that causes the disease, SIR model is a good fit to forecast the end period of COVID-14
19. A mathematical model is an important component in our research because it is the 15 foundation that can guide scholars to identify which concepts are important, what 16 these concepts are like, and how they may be related to each other. They shape the 17 plan for the future, and then influence how the findings are interpreted. Susceptible, 18
infected, and recovered model (SIR) is a very common model that is used in 19
forecasting the disease progression of many infectious diseases. 20
The model first was presented by Kermack and Mckendrick (1927) , in our study we 21 employ the SIR model to predict the peak of the COVID-19 progression and provide a 22 rough estimation of its end. The growth index will be calculated, according to the data 23 from March 2 until April 29. Susceptible, Infected, and Recovered are the main 24 components of the model. The susceptible will be the whole population of the country 25 of Saudi Arabia, which is roughly 34,000,000, because this disease is highly 26 contagious, this data was taken from an authoritative source. The infected and the 27 recovered are secondary data that have been taken from Worldometer. parameter represent the recovery rate whose been infected. 44 All rights reserved. No reuse allowed without permission.
was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. This section will present the results for our SIR calculations. Our time path was 70 4 days as of the study in China calculated their based on 70 days (Pan, et al., 2020) . We 5 assumed at t = 0 we have S(0) = .99 percent of the population is Susceptible and 6 starting infected at I(0) = 0.01, which was one percent of population infected, and 7 recovery rate is zero R(0) = 0. We compared our results with China cases, and it 8
showed similar results to the constant parameters for SIR model that have been used 9
to forecast the epidemic COVID-19 in China. Table 1 showed the constant parameters  10 for SIR model in Saudi Arabia. One important policy Saudi Arabia has implemented 11 is lockdown of all activities and stay at home order which we did not measure to our 12 study. 13 14 15 was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. . https://doi.org/10.1101/2020.05.05.20091520 doi: medRxiv preprint According to the growth index of COVID -19 over time, where it's clear that the 1 increase in number of cases. Timeline clearly indicates a growth in the case index 2 since the first case and its rising but in sustainable rate, which is shown in graph 2. 3 Graph 2: Growth Index of COVID-19 4 5
The data showed an interesting result about the peak of the disease progression. It is 6
projected to occur around the 20 th day after running the model. According to the 7 model, the peak time will be around the 20 th of May. Then the cases will decrease 8 until the 55 th day, which is around June 20 th . 9
Graph 3: Modeling the Spread of the Disease 10 11
According to graph 2, we have data for 55 number of days since the emergence of the 12 first infected person in Saudi Arabia which was on March 3 rd . The parameters have 13 been used according to those data. The model and the parameters allowed us to 14 forecast the time needed to predict the end time of COVID-19. The other countries 15 that had declines took around three months. So, the time was estimated around 70 16 days from the start date of 29 April. 17 Discussion 18 All rights reserved. No reuse allowed without permission.
was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. . https://doi.org/10.1101/2020.05.05.20091520 doi: medRxiv preprint COVID-19 left us uncertain about the nature of the disease, and what will happen in 1 the future. The uncertainty of the disease not only impacts the health sector, but the 2 economy as well. By analyzing the trend of this virus across other countries, the SIR 3 model gave us an optimistic picture about an estimated time to end this pandemic. To 4 make the number of cases less than the hypothetical result, people in Saudi Arabia 5 must follow the same protective measures to prevent the spread of the virus. Health 6 officials implemented productive measures such stay at home orders and ministry of 7
finance have a stimulus package around SAR 120 billion to lessen the Impact of 8 COVID-19 on Economic Activities and Private Sector (Ministry of Finance). This 9 study helps policy makers in considering further action as our model predicts the 10 slowness of spread of COVID-19 and the volume of any stimulus package needed. 11
In the study, SIR model using R software package was employed to predict an end 12 point of COVID-19 in Saudi Arabia. Previous studies have investigated an outbreak 13 of infectious disease and its severity using SIR in different countries and exploring 14 different approaches. For example, COVID-19 outside Hubei in China was less 15 intense in another other region compared to Hubei (Lili Wang et al. 2020). 16 Based on the data above, the peak time will affect around 40% of the Saudi 17
population. As a result of this trend, the peak time will be the most dangerous time for 18 COVID-19 transmission. Prolonged social distancing is needed to prevent 19 catastrophic events in the healthcare system. According to this model simulation, 20 urgent actions are needed to prepare for any critical situations in the healthcare and 21 economic sectors. 22
People must take precaution seriously to end the COVID-19 pandemic and heed the 23 statistics available. The government did great to help citizens and non-citizens there 24 by providing them with the care that they need and overcomes their financial losses. 25
In addition, healthcare providers were privileged by postponing all the debts as an 26 appreciation for their hard work. The Saudi Arabia health officials have already 27
implemented strong predictive measures to reduce the spread of the virus such as stay 28
at home order, closing malls, etc. The infection rate in Saudi Arabia as of today is .93 29 which means every infected person will infect roughly one. This is still a good 30 number to make it easier for health care providers to combat the COVID-19. 31
Therefore, there will be success in delaying and eliminating a sudden increase of 32 cases of COVID-19. Finally, the study suggests a second wave of the COVID-19 will 33 start in 20 to 30 days before it slows down again in Saudi Arabia. was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which this version posted May 9, 2020. . https://doi.org/10.1101/2020.05.05.20091520 doi: medRxiv preprint