Quarantine hotels have seen people infect each other in adjacent rooms, warns a new Lancet paper which claims airborne transmission is being underplayed.
Scientists from the University of Oxford argue that "decades of painstaking research" has revealed that "diseases once considered to be spread by droplets are airborne".
They claim that reports of neighbours in quarantine hotel rooms infecting each other provide evidence that Covid-19 is spread in air - and it's transmission via this route should not be underestimated.
"Long-range transmission of SARS-CoV-2 between people in adjacent rooms but never in each other's presence has been documented in quarantine hotels," reads the comment piece in The Lancet.
Reports of Covid-19 being transmitted in quarantine hotels include a case in New Zealand.
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A Covid-19 positive person was quarantining in a room adjacent to a parent and child who had no symptoms and had tested negative. However, the parent and child later tested positive. Scientists concluded that the virus must have spread through doorways.
Their research, published by the Centers for Disease Control and Prevention, read: "There were no instances where the 3 persons were outside of their rooms at the same time. Nevertheless, footage showed that during routine testing on day 12, which took place within the doorway of the hotel rooms, there was a 50-second window between closing the door to the room of case-patient C and opening the door to the room of case-patients D and E.
"Therefore, we hypothesized that suspended aerosol particles were the probable mode of transmission in this instance, and that the enclosed and unventilated space in the hotel corridor probably facilitated this event."
Scientists writing in The Lancet set out nine other reasons, aside from quarantine hotel transmission cases, which they say adds to evidence that Covid-19 is airborne.
These included that the virus transmits more easily indoors, where ventilation is poorer; the virus has been identified in air filters and building ducts in hospitals treating Covid-19 patients; and animals in cages connected via an air duct have transmitted the virus to each other.
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