Analysis of the Worldwide Corona Virus (COVID-19) Pandemic Trend;A Modelling Study to Predict Its Spread

Muhammad Qasim; Waqas Ahmad; Minami Yoshida; Maree Gould; Muhammad Yasir

Syndrome Coronavirus 2 (SARS-CoV-2) and the disease was renamed COVID-19 by the World Health Organization (WHO) 1 According to WHO, the virus has spread to 197 countries and territories and infected 372,757 people and caused 16,231 deaths (4.35 % mortality rate). 2 This mortality rate of COVID- 19 varies with the addition of new cases. 3 As compared to other two types of Corona virus Severe Acute Respiratory syndrome (SARS) 4 and Middle East Respiratory Syndrome (MERS) 5 which has mortality rate of 9.6% and 34.45 respectively the COVID-19 current mortality rate is almost 4.14%. The average incubation periods for COVID-19 has been reported 4-5 days with an average time of 14 days 6 7 8 from start symptoms to death which is almost similar to MERS. 9 Since human to human transmission of COVID-19 has been confirmed, respiratory droplets and contact are treated as the main path of its transmission so its patients need to quarantine to reduce its spread. 10 A recent study confirmed the spread of COVID-19 through aerosol droplets as SARS-CoV-2 remained viable in aerosols for 3 hours with little reduction in infectious titre from 10 3.5 to 10 2.7 50% tissue-culture infectious dose (TCID50) per litre of air and its reduction rate has been found similar to SARS-CoV-1, from 10 4.3 to 10 3.5 TCID50 per millilitre. While COVID -19 was found to be more stable on plastic and stainless steel than on copper and cardboard, the viable virus was detected up to 72 hours after application to these surfaces 11 which partly explains it lethality. Another unique characteristic of COVID-19 was that its reoccurrence was reported in an oropharyngeal swab test. 12 Further evolution of COVID-19 has been documented and a second strain of the virus was identified and mutations seen in 149 sites across the strains and the strains have been reclassified as L and S. 13 But this claimed was countered by Maclean et al., 2020 who diffused this information by considering it as miss interpretation of the SARS-CoV-2 data, and highlighted its methodological limitations. 14 Since the outbreak started, the reported number of cases and deaths is increasing exponentially despite precautionary measures worldwide. Real-time data reports and forecasting are essential tools for tackling measures and policy formulations to contain the infection. 15, 16 Epidemiological predictions based on real time data create an opportunity to forecast the geographical spread of diseases and also give estimate for burden of case counts to early want to the public health system and paved path for interventions during a pandemic crisis. Exploiting all available real time data is an important aspect of modern pandemic response and helps to take strategic decisions with evidence based support. 17 A few studies have been reported since the start of COVID-19 to model disease prevalence, spread and forecast its expansion. A modelling study conducted based upon the number of cases exported from Whuan to international locations predicted an epidemic doubling time of 6.4 days. 6 Another model reported by the Imperial College of London estimate the potential total number of corona virus cases in Whuan city by using the total volume of international travel from Wuhan over the last two months. 18 Another model was reported to estimate the total number of cases over Diamond Princess Cruise ship by utilizing the number of positive cases on-board at the cruise ship in Japan. 19 To model outbreak size in Wuhan City by