Health experts push for masks to remain mandatory despite COVID-19 alert level drop

Cleaning crews are taking no chances at the Manukau McDonald's - the workplace of one of Wednesday's positive community cases.

The virus flourishes in enclosed indoor spaces.  

And on Thursday the government moved on protective measures in another high-risk setting. COVID-19 Response Minister Chris Hipkins has made masks on public transport a requirement for all New Zealanders.

Aucklanders are familiar with masks on public transport. But it's a bit of a foreign concept for Christchurch commuters - although many this afternoon were already masked up

The mandatory mask requirement will be reviewed on Monday.

But some experts say don’t bother reviewing the rule. Des Gorman, a Professor of Medicine at Auckland University, says it should stay in place.

"Outbreaks of community transmission occur randomly and unexpectedly so it's entirely appropriate and to review it on Monday makes no sense. It's just a good idea. Just do it."

Professor Michael Baker says the change is positive, but overdue, and agrees it should remain compulsory - especially over winter.

"We know that each winter we get around 1500 excess deaths that we would not normally have, most caused by respiratory infections such as influenza which kill around 500 New Zealanders every year."

The tweak of the rules mid outbreak, came as Auckland entered level 2, which meant school was back.

Belmont Primary Principal Bruce Cunningham says even in level 2, they're taking precautions.

"We're not doing our assembly tomorrow morning, and we're asking our parents to drop their children off at the gates but besides, that it's business as usual. "

The only Auckland school not yet enjoying a sense of normality is of course Papatoetoe High School. But all 1550 staff and students must first produce a negative result before walking back through the school gates.

There were some significant new developments on Thursday in the hunt for a source of the original infection.

We know the LSG Sky Chef laundry worker and her family were first to test positive.

Health officials are now investigating a "possible" genomic match to the original infections - a guest who was at this isolation hotel in December.

Dr Ashley Bloomfield says contact tracing is ongoing.

"Guests and household contacts who were at that facility in late December have been contacted to either get a PCR or serology test if they have had symptoms."

Another line of inquiry - mingling at LSG's canteen, where both airside workers and regular workers dined together.

"We are investigating that and that's why we've tested not just the coworkers in the laundry part but all those working at that site," said Dr Bloomfield.

Professor Gorman says the mingling is unbelievable.

"The idea that there are airside and non-airside are mixing each day for lunch beggars belief. What it means is that if you're mixing them then essentially you have to assume they're all airside workers."

LSG - and the nearby airport - are still the major focus of the Ministry's investigations.  

LSG told Newshub it has strict rules inside the canteen. A spokesperson says staff keep two metres apart and must wash their hands before going inside.

"The paths inside the canteen are clearly defined, there are waste bins for used masks at the entrance and all employees must wash their hands before entering the canteen area," a LSG Sky Chefs spokesperson said.

The company says all its staff have returned negative results, but Dr Bloomfield said testing had now been expanded to include all contractors that may have visited LSG's site. In total, there are still 93 test results pending for those workers.