Table 1.
HEPA filter and floor environmental monitoring strategies for the detection of SARS-CoV-2 in five K-6 and K-8 schools.
Table 2.
RT-qPCR primers and probe used for the detection of SARS-CoV-2 and φ6 bacteriophage in environmental samples.
Fig 1.
Positive and negative rooms for SARS-CoV-2 based on floor samples collected in (A) School A, (B) School B, and (C) School C throughout the environmental monitoring study. Episodes with a positive floor sample are marked in red, negative episodes in green, and episodes where no sample was collected are in white. Air filter sampling in Schools A and B started on May 5, 2021 and is denoted by the orange line. No positive air filter samples were detected.
Fig 2.
Positive and negative rooms for SARS-CoV-2 based on floor and HEPA filter samples collected in (A) School D, and (B) School E throughout the environmental monitoring study. Testing dates with a positive floor sample are in red, episodes with a positive air filter sample are in orange, negative episodes are in green, and episodes where no samples were collected are in white. No more than one sample tested positive in a room at any given time. Six negative samples collected from Rooms 27–32 in School E on May 17, 2021 were impossible to link to specific rooms because the tube labels were compromised (not included in the figure). A concluding sampling episode was conducted in School D on June 18, 2021 after school sessions ended to gather further information on the persistence of environmental SARS-CoV-2 RNA in previously positive classrooms and is indicated by the blue line. The previously negative Room 17 was included in the concluding sampling episode as a negative control.
Fig 3.
Frequency distributions of cycle threshold (Ct) values for positive samples from (A) HEPA filters and (B) floors at Schools A, B, C, and D. All positive samples were processed using the MagMAX automated extraction protocol and tested using a SARS-CoV-2 S gene RT-qPCR assay.