The latest outbreak of COVID-19 in Beijing is a warning we can't be complacent and should stay on alert, two infectious disease experts say.
After two months with no cases of the deadly virus, Beijing is back on a "wartime footing". A single case was discovered on Friday, and now there are 51 confirmed infections - all appearing to be linked to a major wholesale food market in the city's Fengtai district.
The outbreak is threatening to spiral out of control, with contact tracing turning up new cases in Liaoning, to the northeast of Beijing.
New Zealand has had no new cases in more than three weeks.
University of Otago expert David Murdoch told The AM Show on Monday it's "pretty unlikely" the virus is still in community transmission here.
"It would require that transmission has been occurring asymptomatically or with very mild symptoms and people haven't been testing. That chance has been diminishing fairly rapidly - it's very, very small."
A new study has found up to 45 percent of all COVID-19 infections could be asymptomatic, still able to spread the disease even if they don't get sick themselves.
"The silent spread of the virus makes it all the more challenging to control," said Eric Topol of Scripps Research in San Diego, which did the research.
Epidemiologist Michael Baker, also of the University of Otago, told Newshub he thinks the virus is gone.
"The Government felt sufficiently confident to say we're moving to alert level 1, which I think is a pretty strong statement there isn't circulation of the virus in New Zealand - or it's very unlikely."
Beijing isn't the only place that's had a new outbreak.
"We've seen similar outbreaks in South Korea, Singapore, on a smaller scale in Hong Kong and also in Australia as well," said Dr Baker. "These are just really important reminders we can not be complacent about this virus."
If the virus is truly gone from our shores, the only way it can return is if someone brings it into the country, and somehow survives the 14-day quarantine process without being detected. Dr Murdoch says being an island nation gives us a "huge advantage" but they aren't airtight.
"We need to focus on the borders, ensuring we don't get new cases coming in. And the fact there are likely to be cases. We'd be fooling ourselves if we thought there weren't going to be cases."
While the virus was first detected in China, the strain that's broken out in Beijing appears to have come from Europe, having evolved since it left Chinese shores earlier this year.
"Our preliminary assessment is the virus came from overseas," government epidemiologist Yang Peng told state media.
"We still can't determine how it got here. It might've been on contaminated seafood or meat, or spread from the faeces of people inside the market."
Prime Minister Jacinda Ardern said she wasn't going to apologise for not opening the borders to our COVID-free neighbours just yet, and Dr Murdoch said that was the right call.
"It's very much dependent on how the rest of the world does. We're in new territory - there are many factors to consider in this."
