Table 1. Frequency of international travel events across demographic and geographical groups, during the period of the traffic light system (17 May 2021 to 26 September 2021) in Scotland.

Factor	Level	Mean weekly travel events per 10 000 population	Kruskal-Wallis test, p value*	Mean weekly cases among travellers per 10 000 population	Kruskal-Wallis test, p value*
Age group	0–19y	5.98	p<0.001	0.25	p<0.001
	20–39y	26.31		0.40
	40–59y	21.69		0.29
	60–79y	12.36		0.12
	80y+	1.73		0.05
Sex	Male	17.29	p=0.569	0.28	p=0.343
	Female	16.13		0.24
NHS Board†	Greater Glasgow and Clyde	18.42	p<0.001	0.34	p=0.025
	Lothian	26.86		0.37
	Lanarkshire	11.93		0.27
	Grampian	20.09		0.24
	Tayside	14.11		0.23
	Fife	14.61		0.22
	Ayrshire and Arran	9.92		0.22
	Highland	10.21		0.13
	Forth Valley	14.25		0.26
	Dumfries and Galloway	5.66		0.12
	Borders	9.50		0.20
	Western Isles	5.82		0.38
	Shetland	6.33		0.00
	Orkney	5.22		0.45
Scottish Index of Multiple Deprivation	1 (most deprived)	10.02	p=0.007	0.22	p=0.310
	2	12.65		0.24
	3	15.49		0.21
	4	18.04		0.27
	5 (least deprived)	25.95		0.35
Month	May (17 May–6 June 2021)	4.40	p=0.002	0.04	p=0.003
	June (7 June–4 July 2021)	7.27		0.09
	July (5 July–1 August 2021)	14.09		0.26
	August (2 August–5 September 2021)	24.56		0.43
	September (6–26 September 2021)	31.95		0.43

^*Test of difference in mean weekly travel events per 10 000 population.

^†NHS Boards are ranked by population size from high-to-low.