I missed blogging about this important preprint when it came out for some reason. “Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients“. I’ve talked in the past about how many of the environmental sampling studies come out are only looking at SARS-CoV-2 RNA and not viable virus. Here’s a nice little hospital study where they looked for viable virus… and sequenced the genome of the virus they found and showed that it came from that patient and not some other source. More troubling even perhaps is the finding that they detected viable virus up to 4.8 m away from the patient… over twice the magic 6 foot spacing that seems to have been burned into popular thinking. Abstract below:
Background – There currently is substantial controversy about the role played by SARS-CoV-2 in aerosols in disease transmission, due in part to detections of viral RNA but failures to isolate viable virus from clinically generated aerosols. Methods – Air samples were collected in the room of two COVID-19 patients, one of whom had an active respiratory infection with a nasopharyngeal (NP) swab positive for SARS-CoV-2 by RT-qPCR. By using VIVAS air samplers that operate on a gentle water-vapor condensation principle, material was collected from room air and subjected to RT-qPCR and virus culture. The genomes of the SARS-CoV-2 collected from the air and of virus isolated in cell culture from air sampling and from a NP swab from a newly admitted patient in the room were sequenced. Findings – Viable virus was isolated from air samples collected 2 to 4.8m away from the patients. The genome sequence of the SARS-CoV-2 strain isolated from the material collected by the air samplers was identical to that isolated from the NP swab from the patient with an active infection. Estimates of viable viral concentrations ranged from 6 to 74 TCID50 units/L of air. Interpretation – Patients with respiratory manifestations of COVID-19 produce aerosols in the absence of aerosol-generating procedures that contain viable SARS-CoV-2, and these aerosols may serve as a source of transmission of the virus.