Reasons for testing over calendar time in the PHS Amsterdam, first RDT, and second RDT datasets in the Netherlands, 2020–2021.
Abbreviations: DCT = digital contact tracing; Index = a person who tested SARS-CoV-2 positive; MCT = manual contact tracing; PHS = public health service; RDT = rapid diagnostic test; Self = testing at one’s own initiative. In Fig 2A, the first vertical dashed line represents the launch of the CoronaMelder app and the second one the change in testing policy, allowing asymptomatic individuals to get tested after exposure to a close contact. Fig 2A is based on 908,060 tests by 560,775 individuals; 2B on 4,126 tests by 4,126 individuals; and 2C on 7,925 tests by 7,925 individuals.