Canberra: As the nations across Asia Pacific struggle with the growing number of Coronavirus cases and deaths, a data point is steering government responses: the share of cases without any clear indication of how the virus pandemic occurred.
These patients cannot be linked to other confirmed infections or existing outbreaks by virus responders, indicating hidden chains of transmission. A growing proportion of such cases in a city's resurgence pushes governments, like in Australia and Hong Kong, to take broad and blunt action, returning entire cities to lockdown-like conditions
"You can hardly contain the outbreak because you have no idea where they will come out next," said Yang Gonghuan, former deputy director general of China's Center for Disease Control and Prevention. "When there's more cases where the origins are unknown, it adds to the difficulty for containment."
In contrast, a low share of cases of unknown origins means that authorities can stay relatively relaxed -- like in South Korea and Japan -- even if total daily new infections reach the hundreds. These countries can take a targeted and nimble approach, shutting down schools or workplaces where clusters are found, but allowing the rest of the population to live normally.
This data point is a telltale sign of whether resurgences across the world will flare up into bigger waves, and if residents need to gird themselves for a return to lockdown. Here's a breakdown of how the places fighting flareups are using the number to guide their responses: The Asian financial hub enjoyed three months of normal life before a surprise resurgence this month that looks to set to be its worst wave ever. Infections of "unknown origins" have surged to half of all new local cases, indicating that they're emerging from all corners. The former British colony has reacted swiftly, levying its strictest-ever restrictions on the city of 7.5 million.
Schools started summer break early while bars, gyms and beaches have been shut. Public gatherings are limited to four people and those refusing to wear masks on public transport will be fined HK$5,000 ($645).