A fresh outbreak of covid-19 in New Zealand following its elimination there is a sobering reminder of how the virus can evade the toughest defences. The country has responded swiftly, but it remains to be seen if it can beat the virus again.
New Zealand declared zero remaining covid-19 cases on 8 June after enacting one of the strictest lockdowns in the world. Restrictions were eased, but it has since sought to keep the virus out with tight border controls that include a ban on international visitors, quarantining its citizens who return from abroad and requiring protective equipment for all airport and seaport workers.
These measures allowed New Zealand to go 102 days without recording any new locally acquired covid-19 cases. However, on 11 August, the country was rocked by news that four members of a family in Auckland had tested positive for the virus, without any identifiable source of infection.
“It’s something we had been preparing for, but it’s still a shock when it happens, particularly after having a three-month dream run,” says Michael Baker at the University of Otago, who sits on the New Zealand government’s covid-19 advisory panel.
In line with its “go hard, go early” strategy for the virus, the government put Auckland in lockdown the next day, banning residents from leaving home for non-essential reasons.
Authorities in Auckland also began testing anyone with even remote connections to the new cases, as well as all port workers, staff at quarantine facilities and anyone with cold and flu symptoms, in an effort to find out where the virus had come from and how far it had spread.
By 18 August, this testing blitz had identified another 65 cases connected to the original family cluster, as well as one in a man employed at a quarantine facility.
Baker is confident the virus has been caught early and has had little chance to spread, since almost all cases are connected to the same cluster and the number of new daily cases isn’t rising. “All the signs are very positive at the moment that we’ll be able to contain it again,” he says.
Genetic sequencing suggests the new outbreak has been caused by a coronavirus strain that recently entered New Zealand. It most closely resembles a strain that is currently circulating in England, but how it sneaked into New Zealand is still a mystery.
One suggestion is that it entered the country in a frozen food shipment, since one member of the Auckland family that first tested positive works at a chilled food warehouse. “But so far there’s been no evidence for this infection route,” says Amanda Kvalsvig at the University of Otago.
Alternatively, a returning citizen with the virus may have incubated it for longer than normal – so it wasn’t picked up by testing during quarantine – and then entered the community, says Siouxsie Wiles at the University of Auckland.
Although the new outbreak is a psychological blow, most Auckland residents seem to have willingly returned to lockdown, says Wiles. This may be because they have seen events play out in countries that have been slow to react to new outbreaks, she says.
Australia, for example, which also came tantalisingly close to eliminating covid-19, took more than a month to reintroduce stay-at-home orders in the state of Victoria after the virus escaped from a hotel used for quarantine. As a result, Victoria now has more than 7000 active cases and a rapidly mounting death toll.
Wiles believes that Auckland should remain in lockdown until the number of new daily cases returns to zero, which could be a week or two away. “The next few days will be crucial, so we’re just watching and waiting,” she says.
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