Azimi S S, koohi F, Aghaali M, Nikbakht R, Mahdavi M, Mokhayeri Y, et al . Estimation of the basic reproduction number (𝑅0) of the COVID-19 epidemic in Iran. Med J Islam Repub Iran 2020; 34 (1) :668-675
URL:
http://mjiri.iums.ac.ir/article-1-6630-en.html
Seyyedeh Sara Azimi ,
Fatemeh Koohi ,
Mohammad Aghaali ,
Roya Nikbakht ,
Maryam Mahdavi ,
Yaser Mokhayeri ,
Rasool Mohammadi ,
Niloufar Taherpour ,
Mehran Nakhaeizadeh ,
Davood Khalili ,
Hamid Sharifi ,
Seyed Saeed Hashemi Nazari
Prevention of Cardiovascular Disease Research Center, Department of Epidemiology, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran , saeedh_1999@sbmu.ac.ir
Abstract: (3165 Views)
Background: Estimation of the basic reproduction number of an infectious disease is an important issue for controlling the infection. Here, we aimed to estimate the basic reproduction number (𝑅0) of COVID-19 in Iran.
Methods: To estimate 𝑅0 in Iran and Tehran, the capital, we used 3 different methods: exponential growth rate, maximum likelihood, and Bayesian time-dependent. Daily number of confirmed cases and serial intervals with a mean of 4.27 days and a standard deviation of 3.44 days with gamma distribution were used. Sensitivity analysis was performed to show the importance of generation time in estimating 𝑅0.
Results: The epidemic was in its exponential growth 11 days after the beginning of the epidemic (Feb 19, 2020) with doubling time of 1.74 (CI: 1.58-1.93) days in Iran and 1.83 (CI: 1.39-2.71) in Tehran. Nationwide, the value of 𝑅0 from February 19 to 29 using exponential growth method, maximum likelihood, and Bayesian time-dependent methods was 4.70 (95% CI: 4.23-5.23), 3.90 (95% CI: 3.47- 4.36), and 3.23 (95% CI: 2.94-3.51), respectively. In addition, in Tehran, 𝑅0 was 5.14 (95% CI: 4.15-6.37), 4.20 (95% CI: 3.38-5.14), and 3.94 (95% CI: 3.45-4.40) for exponential growth, maximum likelihood, and Bayesian time-dependent methods, respectively. Bayesian time dependent methods usually provide less biased estimates. The results of sensitivity analyses demonstrated that changes in the mean generation time affect estimates of 𝑅0.
Conclusion: The estimate of 𝑅0 for the COVID-19 ranged from 3.94 to 5.14 in Tehran and from 3.23 to 4.70 in nationwide using different methods, which were significantly larger than 1, indicating the potential of COVID-19 to cause an outbreak.