The basic reproduction number and prediction of the epidemic size of the novel coronavirus (COVID-19) in Shahroud, Iran

Ahmad Khosravi; Reza Chaman; Marzieh Rohani-Rasaf; Fariba Zare; Shiva Mehravaran; Mohammad Hassan Emamian

The trend of R 0 over time provides a measure of the effectiveness of control and prevention strategies in the community, and to control an epidemic, the goal is to reduce and keep R 0 below the value of 1 [13] . In the present study, the estimated R 0 of 2.7 (95% CI, 2.1 to 3.4) during the early stage of the epidemic is in line with previous estimates [10, [14] [15] [16] . However, higher estimates of R 0 have been reported in larger populations [17, 18] . For precise estimation of R 0 , certain conditions must be met which include the precise detection of cases in the early stages of the epidemic, restricting the calculation to a small timeframe [12] , and choosing the appropriate estimation method [13, 19] . For precise detection of cases, all suspected cases (according to the screening protocol) and cases who have had close contact with confirmed cases should undergo viral nucleic acid testing. In Shahroud, there were 1055 suspected cases, and 405 of them tested positive. However, in the early stages of the epidemic in Iran, there was limited capacity for testing, and the calculated R 0 may be an underestimation.