Environmental contamination of SARS-CoV-2 on surfaces, air-conditioner and ventilation systems

Abstract

Background: COVID-19 can be transmitted directly through respiratory droplets or indirectly through fomites. SARS-CoV-2 has been detected on various environmental surfaces, air samples and sewage in hospital and community settings.

Methods: Environmental samples were collected from a ferryboat during a COVID-19 ongoing outbreak investigation and a nursing home and from three COVID-19 isolation hospital wards and a long-term care facility where asymptomatic COVID-19 cases were isolated. Samples were tested by real-time reverse transcriptase-polymerase chain reaction.

Results: SARS-CoV-2 was detected on swab samples taken from surfaces of food preparation and service areas, hospital isolation wards, an air exhaust duct screen, air-conditioning filter, sewage treatment unit and air sample during investigations conducted in response to COVID-19 outbreaks on a ferryboat, nursing home, isolation facility and COVID-19 hospital wards.

Discussion: Food preparation areas and utensils can be contaminated during COVID-19 outbreaks. Respiratory droplets/nuclei from infected persons can be displaced by the air flow and deposited on surfaces. It can be assumed that in the same manner, air flow could transfer and deposit infected respiratory droplets/nuclei from infected persons to the mucous membranes of persons standing against the air flow direction.

Keywords: Air; Air-conditioning system; Airborne; COVID-19; Disinfection; Food safety; Nursing home; Outbreak; SARS-CoV-2; Sewage; Ship; Surfaces; Ventilation system; Waste.