Figure 3.

Heatmap of unique mutations found in wastewater sequencing from the Ruhleben wastewater treatment plant from 7 August to 26 November 2023 showing fingerprint variants for clade 23I. WWTP Ruhleben is shown as an example since it is the largest WWTP in Berlin covering 1.6 Mio inhabitants, the other WWTPs are shown in the supplementary materials. Fingerprint mutations are exclusive for each lineage and can be used to determine the presence of a variant with a high degree of confidence. Although the fingerprint mutations for JN.1 (BA.2.86.1.1, clade 23I) were first detected in September, their significance was unknown as JN.1 would only be defined as a Pango-lineage on 29 September 2023 and was integrated in Nextstrain on 26 October 2023. Only as of the middle of October, the number and frequency of known fingerprint mutations allowed for the determination of JN.1.