Table 1.

Confirmed cases of SARS-CoV-2 with exposure in Switzerland and abroad. Percentages for cases with reported exposure correspond to all cases with known exposure. Scenario (a) Missing at random. Scenario (b) Lower limit (50% of imports in scenario (a). Scenario (c) Upper limit (150% of imports in scenario (a).

	Summer 2020 (Jun–Sep)	Summer 2021 (Jun–Sep)
Total confirmed cases	22,919	145,840
Confirmed cases with known exposure	12,088 (53%)	4,368 (3%)
Confirmed cases with exposure in Switzerland	8,812 (73%)	3,258 (75%)
Confirmed cases with exposure abroad	3,276 (27%)	1,110 (25%)
Total number of imports (scenario a)	6,211	37,061
Total number of imports (scenario b)	3,106	18,530
Total number of imports (scenario c)	9,317	55,591