Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients

TLDR

Understanding the particle size distribution and environmental contamination patterns of SARS‑CoV‑2 is essential for infection prevention policies. The study screens surface and air samples from hospital rooms of COVID‑19 patients for SARS‑CoV‑2 RNA. Sampling was performed in three airborne infection isolation rooms in the ICU and 27 AIIRs in the general ward. Of 245 surface samples, 56.7 % of rooms had at least one contaminated surface, with high‑touch surfaces positive in 66.7 % of patients in the first week and 20 % thereafter; air sampling in three general‑ward AIIRs detected SARS‑CoV‑2 particles >4 µm and 1–4 µm in two rooms despite 12 air changes per hour, indicating a need for further study of airborne transmission.

Abstract

Abstract Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. Here we screen surface and air samples from hospital rooms of COVID-19 patients for SARS-CoV-2 RNA. Environmental sampling is conducted in three airborne infection isolation rooms (AIIRs) in the ICU and 27 AIIRs in the general ward. 245 surface samples are collected. 56.7% of rooms have at least one environmental surface contaminated. High touch surface contamination is 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 = 0.01, χ 2 test). Air sampling is performed in three of the 27 AIIRs in the general ward, and detects SARS-CoV-2 PCR-positive particles of sizes >4 µm and 1–4 µm in two rooms, despite these rooms having 12 air changes per hour. This warrants further study of the airborne transmission potential of SARS-CoV-2.