Presence of SARS-CoV-2 on Hospital Surfaces Before and After Disinfection: A Case Study of Two Large Hospitals in Urmia, Iran.

Abstract

Background and objectives: Although inhalation of contaminated air and contact with contaminated surfaces were known as main routes of SARS-CoV-2 transmission, the degree of surface contamination in actual hospital environments and the effectiveness of regular disinfection remained crucial questions. The aim of the present study was to investigate the presence of SARS-CoV-2 on various hospital surfaces before and after disinfection in two large hospitals of Urmia megacity, Iran.

Methods: In this cross-sectional study, a total of 144 samples were collected from high-touch surfaces inside and outside of patient rooms, both before and after disinfection. Samples were taken using sterile swabs and SARS-CoV-2 was identified via real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR).

Results: SARS-CoV-2 was found on 38% (8/21) of surfaces within patient rooms in Hospital A and 20% (3/15) in Hospital B before disinfection. Rates of contamination outside patient rooms were 7/21 in Hospital A and 7% (1/15) in Hospital B. Especially, SARS-CoV-2 was positive in 81.8% of ventilation duct dampers (air outlet covers of mechanical ventilation) from Hospital A and 66.7% from Hospital B. Most importantly, no SARS-CoV-2 was found in any samples collected following disinfection (using benzalkonium chloride and 70% ethanol with a 15-minute contact time).

Conclusion: The results revealed a high likelihood of SARS-CoV-2 being present on surfaces near patients. Many samples from ventilation duct dampers also tested positive, which pointed to the role of airborne transmission. Importantly, after cleaning, no SARS-CoV-2 was detected on any surfaces, showing that standard hospital cleaning practices effectively lower surface contamination.