9 seconds apart: how Omicron could have spread from 2 people to a Hong Kong kindergarten teacher in a tunnel
- All three wore masks, and teacher had no direct contact with the pair
- Government pandemic adviser says transmission still possible because surgical masks guard against large droplets, but virus could still reach eyes
It could take just a brief encounter in an MTR station for the Omicron variant to transmit from one person to another, Hong Kong health officials said on Thursday.
Contact tracing of a previously unlinked, positive case found possible transmission pathways, revealing new details about the infection of a 26-year-old kindergarten teacher who lived in Mei Foo Sun Chuen.
She was on her way to work when she encountered two infected people in an MTR station tunnel.
CCTV footage and her Octopus card transaction history showed that she went through a tunnel at a Mei Foo MTR exit at almost the same time – just nine seconds apart – as the two people last Friday. All three wore masks, and the teacher did not have any direct contact with the pair.
Government pandemic adviser Professor David Hui Shu-cheong explained that such transmission is possible, given that the transmissibility of the Omicron variant is four to eight times higher than the Delta variant.
“If the index [patient] was near the kindergarten teacher, the wind direction could carry the droplets [containing virus] to the teacher,” he said. “Although a surgical mask could protect you from large droplets, it could still reach your eyes or leak in when you rub your eyes and nose.”