Coronavirus: The search for ‘patient zero’ in global spread

The outbreak, which has killed at least 1,400 people and spread to more than two dozen countries, began in the Chinese city of Wuhan in late 2019.

But authorities believe it may have been at a luxury Singapore hotel that the virus went global.

In late January, a conference was held at The Grand Hyatt Singapore by British gas analytics firm Servomex.

Health authorities believe at least one of the 109 attendees, most of them foreigners, was carrying the virus.

As the attendees returned home the virus was spread to five countries infecting over a dozen people.

Finding out who that original “patient zero” was could be key to containing the outbreak by tracing all those potentially exposed.

“So this is about contact tracing. We do feel uncomfortable, obviously, when we diagnose a patient with the illness and we can't work out where it came from,” Dale Fisher, chair of the Global Outbreak Alert and Response Network coordinated by the World Health Organization (WHO), told Reuters.

“Therefore the containment activities are less effective.”

But so far, the search has come up empty. Tests of Chinese delegates, including some from Wuhan, came back negative, Servomex has said.

And despite efforts to contain the virus it has kept spreading.

Cases linked to the conference have surfaced in Malaysia, South Korea, Spain, France and the UK.

Experts have compared the Singapore meeting to the international outbreak of the SARS virus in 2003, when a sick Chinese doctor at a Hong Kong hotel spread the disease around the world in what is known as a "super-spreading" incident.

However, the WHO has said it is still too early to tell if the Singapore incident is a super-spreading event.