Recently released research indicates that it is possible to catch COVID-19 from someone who is in a completely different room.
The research is expected to be published in the March 2022 edition of Emerging Infectious Diseases journal and the Centers for Disease Control and Prevention shared it as an early release. There may be changes before final publication.
According to the research, an episode of airborne transmission of the SARS-CoV-2 delta variant occurred between people who were in “separate nonadjacent rooms 2.135 meters (7 feet) apart,” and “this conclusion is supported by multiple lines of evidence.” Scientists based this conclusion on an incident that occurred in New Zealand – where international arrivals are quarantined to undergo COVID screenings – this summer.
A traveler arrived in New Zealand July 16 from the Philippines and was placed in a managed quarantine facility, said the research. They tested positive for COVID-19 on July 17 and were transferred to a managed isolation facility on July 19. Although asymptomatic, the individual was considered infectious through July 27 and released from the isolation facility on July 31.
Before the traveler from the Philippines arrived in New Zealand, five people traveling together from the United Arab Emirates arrived in the country on July 14. They were also quarantined in a managed quarantine facility. One member of the group, identified as Person E, had a positive test result they day they arrived in New Zealand, so the group was transferred to the managed isolation facility the following day.
At the facility, the group occupied two rooms across the hall from the person from the Philippines, who is identified as Person A. On the day Person A arrived at the facility, Person E was experiencing upper respiratory tract infection symptoms and another positive test the day before.
Another member of the group from the United Arab Emirates identified as Person B experienced upper respiratory tract infection symptoms on July 17 and 18. They tested negative for COVID-19 on July 18 but positive for rhinovirus/enterovirus. Eventually, Person B and two other members of the group tested positive for SARS-CoV-2 from July 27 to Aug. 9.
The fifth member – who had received two doses of the Pfizer BioNTech vaccine and was the only one in the group who was vaccinated – never tested positive, despite sharing a room with the others. All stayed at the isolation facility through Aug. 25.
Furthermore, the three members of the group who tested positive after arriving in the group did not have the same strain of SARS-CoV-2 as Person E. They did have the same strain as Person A, despite having no direct contact with them. No other persons within the facilities had SARS-CoV-2 genomes linked to these cases.
“We concluded that an episode of airborne transmission of SARS-CoV-2 Delta variant occurred between person A, the index case-patient,” and the three members of the group from the United Arab Emirates who tested positive after arriving in New Zealand, said researchers.
According to their study synopsis, security camera footage revealed four “brief episodes of simultaneous door opening” while Person A was infectious, all for intervals of three to five seconds. For the most part these incidents occurred when the travelers opened their doors to receive food.
Each room at the facility was equipped with a free-standing high efficiency particulate air (HEPA) filter, which recirculated and filtered air within the room. However, the filter did not affect air movement into or out of the room. A total of 4 free-standing HEPA filtration units were present in the block corridor where the travelers stayed.
Scientists believe that the virus spread by airborne transmission as there is no evidence Person A had contact with the other travelers.
Since Person A did not leave their room at any point during their infectious period, there was likely a high concentration of viral aerosols accumulating in the room. When their door opened, researchers hypothesize that airborne particles rapidly diffused down a concentration gradient, across the corridor, and a nearby HEPA filter could have aided in aerosol movement.
Aerosols could have also flowed under the doors of the rooms, researchers said.
“These findings are of global importance for coronavirus disease public health interventions and infection control practices,” said the researchers.
At the New Zealand facility immediate changes were made to food delivery and health check protocols to avoid opening doors at the same time and to the position of HEPA units.
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