Dr Zoë Hyde(1/4) Respiratory viruses are much more likely to spread indoors than outdoors, but outdoor super-spreading events can still occur if the conditions are right.
A new study describes a SARS-CoV-2 outbreak affecting 131 people at a night market. 🧵
(2/4) The outbreak happened when a family of 3 people infected with the omicron BA.5.2 variant visited a night market in Zhejiang Province, China, in July 2022. They spent 1 hour and 4 minutes at the market.
On the evening of the outbreak, it was warm (27 degrees Centigrade), humid, and there was very little wind. Most of the market stalls had big umbrellas and it was crowded. The market had a capacity of 5,000 people.
(3/4) During their 1 hour and 4 minutes at the market, the index cases infected 131 people.
Researchers worked out that infectious aerosols were able to remain suspended in the air for up to 1 hour and 39 minutes.
Why were so many people infected?
👉 Very little breeze
👉 Narrow aisles with umbrellas overhead
👉 2 cases did not wear masks
👉 Cases had to speak loudly due to the noisy environment
Jonathan"39 minutes" is a very optimistic impression of significant values hah