Figure 2.

Measured SARS-CoV-2 RNA viral load in PCR-positive environmental samples, stratified by contacts' URT PCR status and baseline serological status

Only contacts linked to one or more PCR-positive environmental samples are depicted. (A) Primary cases' hand-swab RNA viral load (median 82·09 copies per mL, IQR 46·09–1082·29). (B) Household surface-swab RNA viral load (226·58, 101·38–602·51). (C) Contacts' hand-swab RNA viral load (117·66, 21·75–244·39). The measured environmental viral loads do not differ by contacts' URT PCR status, as shown by the p values in each panel (Mann-Whitney U test). All positive primary case hand swabs and surface swabs were collected on day 0, whereas contacts' hand swabs were positive on day 0 (n=16) and day 7 (n=6). Environmental samples with more than 5 RNA copies per mL were considered PCR positive. URT=upper respiratory tract.