For detailed information about the methods and data used here, please refer to our pre-print

https://www.frontiersin.org/articles/10.3389/fphy.2020.00289/full

https://www.frontiersin.org/articles/10.3389/fphy.2020.00289/full

Data is obtained from three sources:

Ministry of Health and Medical Education of I.R. Iran

World Health Organisation (WHO)

Worldometers.info/coronavirus

Ministry of Health and Medical Education of I.R. Iran

World Health Organisation (WHO)

Worldometers.info/coronavirus

**How do we model the spread of COVID-19?**

We use an extended version of the classical susceptible-exposed-infected-recovered (SEIR) mathematical model in epidemiology with homogenous mixing assumption. The model distinguishes between recovered and removed (or death). We assume 50 million of the entire population of Iran is susceptible. In some of the scenarios, we also assume 80, 30 and 10 million susceptible individuals. We estimate the basic reproduction number, known as R0, from reported data from Iran in various selected time windows using a generalized Least Squares Method (LSM) where the estimation problem is formulated as an optimization to minimize the root mean square error (RMSE) of the number of active cases, recovered cases and deaths. Depending on the selected time window, we have estimated R0 between 2 and 5 which is consistent with what is estimated in other countries including China, Italy and South Korea.

Source: Network Science by Albert-László Barabási, Chapter 10. http://networksciencebook.com/chapter/10#SIR

**How do we define the number of "active cases"?**

Number of active cases = (total number of infected cases - total recovered - total death)

Note that the total number of infected case is cumulative and will continue to rise, albeit with slowing rate if the spread starts diminishing. However, the number of active cases has a peak, initially starting as an exponential growth and then gradually slow down. The number of active cases reduces after the peak until it reaches zero or near zero when the virus is no longer spreading.