Table 4.

Ratio of China-USA collaboration in formal coronavirus related publications

	Mean (standard deviations)
	Pre-COVID-19	COVID-19
		Period I	Period II	Period III
Rate in overall articles	0.038	0.048**	0.027***	0.025***
	(0.19)	(0.215)	(0.161)	(0.157)
Rate in international teamed articles	0.2	0.184***	0.109	0.101**
	(0.325)	(0.388)	(0.311)	(0.301)
Rate in Chinese articles	0.537	0.478	0.539	0.515
	(0.499)	(0.501)	(0.499)	(0.5)
Rate in USA articles	0.228	0.388***	0.219	0.204*

^*, **, ***denote that the difference between mean rates of each COVID-19 period versus pre-COVDI-19 is significant at 90%, 95%, 99% confidence level