Table 2.

The reproduction number of COVID-19 before and after the introduction of control measures for the countries. The time and type of conducting the control measures was defined in the corresponding reference.

The reproduction number	Before control measures	After control measures	Data Type	Model	Time	Reference
China	1 ∼ 4	<1	The daily case data	The classic SEIR model, the model formulated with the use of renewal equations, Poisson process, the extension of a classic SEIR model to seven compartments, the SIR model stratified by age groups and contact patterns	12/8/2019 to 3/8/2020	[42], [43], [44], [46], [47], [48], [49]
Niger	0.4 ∼ 3	Around 1	The daily case data	Poisson process	3/19/2020 to 7/4/2020	[45]
Japan	4.66	1.79	The daily case data	A susceptible-infectious-recovered-deceased model	1/22/2020 to 5/14/2020	[50]
United States	4.02	1.51	The daily case data	The likelihood-based estimation procedure	3/17/ 2020 to 4/1/2020	[52]
Canada	2	<1	The daily case data	The likelihood-based estimation procedure	3/20/2020 to 6/10/2020	[53]
France	4 ∼ 5	<1	The death data	A set of statistical models (death model and infection model)	2/2020 to 5/4/2020	[57]
Italy	3 ∼ 4	<1	The death data	*	*	[57]
Spain	4 ∼ 6	<1	The death data	*	*	[57]
UK	Around 4	<1	The death data	*	*	[57]
Belgium	4 ∼ 6	<1	The death data	*	*	[57]
Germany	3 ∼ 5	<1	The death data	*	*	[57]
Sweden	2 ∼ 3	<1	The death data	*	*	[57]
Switzerland	3 ∼ 4	<1	The death data	*	*	[57]
Austria	3 ∼ 5	<1	The death data	*	*	[57]
Norway	2 ∼ 4	<1	The death data	*	*	[57]
Denmark	3 ∼ 5	<1	The death data	*	*	[57]

*Same with above one.