Another quick COVID19 Journal club in the Built Environment. This study (“Detection of Air and Surface Contamination by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Hospital Rooms of Infected Patients” combined air and surface sampling to look at the distribution of the virus in a healthcare setting with infected patients. This is another RNA-based study though, so while they found virus in most of the places one would expect… the viability of the virus wasn’t determined. Abstract below:
Background: Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. Objective: To detect the surface and air contamination by SARS-CoV-2 and study the associated patient-level factors. Design: Cross-sectional study. Setting: Airborne infection isolation rooms (AIIRs) at the National Centre for Infectious Diseases, Singapore. Patients: COVID-19 inpatients with a positive PCR test for SARS-CoV-2 within 72 hours before the environmental sampling. Measurements: Extent of environmental surface contamination in AIIRs of 30 COVID-19 patients by PCR on environmental swabs. The particle size distribution of SARS-CoV-2 in the air was measured using NIOSH air samplers. Results: 245 surface samples were collected from 30 rooms of COVID-19 patients, and air sampling was conducted in 3 rooms. 56.7% of the rooms had at least one environmental surface contaminated, with 18.5% of the toilet seats and toilet flush button being contaminated. High touch surface contamination was shown in ten (66.7%) out of 15 patients in the first week of illness, and three (20%) beyond the first week of illness (p = 0.010). Air sampling of two COVID-19 patients (both day 5 of symptoms) detected SARS-CoV-2 PCR-positive particles of sizes >4 μm and 1-4 μm. In a single subject at day 9 of symptoms, no SARS-CoV-2 PCR-positive particles were detected. Limitations: Viral culture results were not available to assess the viability of the virus contaminating the air and surface. Conclusion: Environmental contamination was detected in rooms with COVID-19 patients in early stages of illness, but was significantly less after day 7 of disease. Under AIIR conditions, SARS-CoV-2 respiratory particles can be detected at sizes 1-4 μm and >4 μm in diameter in the air which warrants further studies.
In addition to the usual precautionary steps recommended by the CDC and others, it is also very beneficial to maintain indoor air relative humidity between
40% – 60%!
#COVID19 #RH40to60
I 100% agree with Michael Siwicki!