Fig. 5.

Positivity rate dependent on sampling method and incidence rates. a. Rate of positive students identified with different sampling methods used for pooled testing in total numbers and percentage. Lolli method: red pie; buccal swab: yellow pie; oropharyngeal swab: blue pie. b. Number of SARS-CoV-2 positive students (right Y-axis) and incidence rate (left Y-axis, per 100,000 individuals) per week in secondary and primary schools. Note that week 1 contains asymptomatic prevalent individuals many of whom were identified on the first day of testing. Secondary schools: blue bars; primary schools white bars. Incidence rate: hatched bars; cases: open bars. c. Cumulative incidence (per 100,000; three-week period) identified in a high burden school situated in a city district with lower socioeconomic status (secondary school 4, blue bar), a low burden school (secondary school 5, white bar), in the entire study (all 14 schools, light grey bar), the general population of the respective Cologne district of secondary school 4 (medium grey bar), the general population of the city of Cologne (dark grey bar) and the entire country (Germany, black bar) (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.).