SARS-CoV-2 on Surfaces and HVAC Filters in Dormitory Rooms

While there have been many studies of SARS-CoV2 contamination in hospital patients' rooms, less is known about the virus' presence in nonhealthcare environments, which is where most transmission takes place. We investigated virus contamination in university dormitories housing students who were in quarantine or isolation. We collected surface swab samples and heating, ventilation, and air conditioning (HVAC) filters from 24 rooms that had been occupied by students who tested positive for COVID-19, and we measured viral RNA by the quantitative reverse transcription polymerase chain reaction (RT-qPCR). We detected viral RNA on or in 15/21 (71.4%) HVAC filters, 71/125 (56.8%) surface samples, and 4/6 (66.7%) bathroom exhaust grilles in the two dormitories combined. Viral RNA was present in all five types of surface samples, including sink handles, sink countertops, floors near the sink, door handles, and thermostat panels. Viral RNA levels on surfaces varied widely, from 10 to >10(4) gene copies per swabbed area of similar to 10 cm x 10 cm. Additionally, we tested the infectivity of samples with a Ct value lower than 33, and none of them were positive. This information will be valuable for assessing the risk of airborne and fomite transmission of COVID-19.