Mandatory masking and Delta – Expert Reaction

Masks will be mandatory in essential stores from tomorrow, as the government announces the new rule to help curb the Covid-19 Delta outbreak.

Masks will be required for everyone over 11 years old in places like supermarkets, bus terminals, and taxis. There is now a total of seven community cases – with most so far aged in their 20s. 

The SMC asked experts to comment on the new mask rules and other updates from the 1pm press conference.

Lesley Gray, Senior Lecturer, Department of Primary Health Care & General Practice, University of Otago, comments:

“Mandating masks when visiting essential services is a good move given all we know about the Delta variant of Covid-19 at this point. Delta is highly transmittable and we do not yet know where the first case currently contracted this Australian variant of Delta from. Wearing a mask protects our essential workers and reduces risk of transmission from this airborne virus.”

“The Delta variant is very easily transmitted from person to person. Unvaccinated people are at greatest risk. Being vaccinated reduces not only risk of transmission but also the severity of illness for someone with the virus. With the possible high numbers of people who would have also visited the ‘places of interest’ known so far – this could be a larger cluster quite quickly compared to the August 2020 Auckland outbreak. Locking down quickly will limit and minimise transmission if everyone ‘plays their part’ and keeps within their bubble, makes only essential trips to supermarkets/pharmacies etc, remembers hand hygiene, scans into essential businesses and if you have any covid or cold symptoms find out how to get a test and isolate, preferably by yourself (appreciating how difficult this is in many households). One of the things about the Delta variant was how quickly it transmitted to other household members in the Australian outbreaks.”

No conflict of interest declared.

Associate Professor Collin Tukuitonga, Associate Dean Pacific, Faculty of Medical and Health Sciences, University of Auckland, and Pasifika Medical Association (PMA) member, comments:

“The delta variant is much more infectious. One case of delta could infect up to 9 people and then those 9 would infect another 9. It rises exponentially which basically means the disease will spread rapidly in the community. It spreads quite quickly so I thought the Alert Level 4 decision was the right decision because we want to try and get on top of it.

“Covid-19 tends to affect people with underlying medical conditions like diabetes, obesity and respiratory conditions. Our Pacific communities have those underlying conditions which puts them at a higher risk so that’s why it is of a particular concern for us. Where you have a virus that spreads quickly like the delta variant – the conditions of our people, the housing and overcrowding, means it would spread like wildfire. That’s why we want to get on top of this as quickly as possible.

“I think the government is doing the right thing and that we should do our part and stay home, minimise interacting with others and follow the public health advice. People are generally aware of the risks and will take the actions necessary to reduce the risk to their family members.

“We’ve done this before and we’ve been successful and I’m pretty sure if we do it again, we’ll come out good as well.”

No conflict of interest declared.

Dr Rachelle Binny, Mathematical Modeller, Manaaki Whenua – Landcare Research; and Principal Investigator, Te Pūnaha Matatini, comments:

“Previous modelling by Te Pūnaha Matatini, led by Nic Steyn and Alex James, showed that if the first case detected in the community is a person without a direct link to arrivals or MIQ facilities, then a significant number of infections have already likely occurred and a lockdown would be needed to control the outbreak. With the highly transmissible Delta variant, the outbreak size is expected to be considerably larger than if we were dealing with the original virus strain.

“If contact tracing and genome sequencing can identify when the virus first leaked into New Zealand from NSW, we’ll be in a better position to estimate how far down the chain of transmission these new cases are and how many additional community cases might be out there.

“As well as the current outbreak size, another measure affecting how long we need to spend in alert level 4 is the R number. We need to get the R number below 1 to bring case numbers down. In the March 2020 outbreak we estimated that alert level 4 was effective at pushing R down to 0.3-0.55 but with the Delta variant, the R number is about double that of the original strain. If we all do our bit by staying in our bubbles and wearing face masks when visiting essential services, hopefully alert level 4 will still be enough to push R below 1, but case numbers may drop more slowly than we’ve seen in past lockdowns.”

Conflict of interest statement: I am partly funded by MBIE for research on mathematical modelling of COVID-19.

Dr Joel Rindelaub, Aerosol Chemist, University of Auckland, comments:

“Expanding mask mandates from public transit to other indoor areas is a wise move in the fight against SARS-CoV-2, as indoor environments are high risk locations for COVID-19 transmission and super spreader events, due to their decreased air ventilation.

“Thanks to the increased transmissibility of the Delta variant, the US Center for Disease Control recently renewed their mask use recommendations. Thus, it makes sense for New Zealand to use what other countries have learned to help shape protection strategies against the ever-changing coronavirus.

“The Delta variant is a new threat, and we need to take new action to help fight it.”

No conflict of interest declared.

Professor Michael Plank, Te Pūnaha Matatini and University of Canterbury, comments:

“At this stage modelling suggests that somewhere in the range of 50 to 120 people could have been infected prior to yesterday’s positive test result. Many of these will still be in their incubation period so it may take a few days to see them come through in the case numbers.

“There is a wide range of uncertainty in the outbreak size at this stage. If it turns out a close link can be established with a case who has returned from NSW via the MIQ system, the outbreak could be at the small end of the scale. If the source case travelled to NZ from another Australian state not required to go into MIQ, the virus could have been spreading undetected for some time and the outbreak could be much bigger.

“Genome sequencing results from MIQ are expected later and these will help narrow down the possibilities. Negative wastewater results are a good sign though we need to see results from more recent samples to have confidence.”

Conflict of interest statement: I am partly funded by MBIE for research on mathematical modelling of COVID-19.

Associate Professor Arindam Basu, College of Education, Health & Human Development, University of Canterbury, comments:

“Mandatory masking is particularly important now (it was always necessary and many public health scientists have advocated for months!), because of source control. The Covid-19 delta variant is particularly problematic for young people (see this report: “Prevalence in those aged 5-49 was 2.5 times higher…compared with those aged 50 years and above”).
“There are some unique aspects of this epidemic – few people infect many but most people will not infect anyone. The epidemic spreads via superspreaders, and superspreading is particularly problematic with the delta variant. There is a need to identify the network of people who are connected, so we are probably looking at few cases at this stage, and more people will emerge, possibly in different parts of the country.”

Dr Sarb Johal, registered clinical psychologist, comments:

Note: This comment is excerpted from Sarb Johal’s blog.

“We know that the people who seemed to do better in the lockdowns last year seemed to have absorbing activities that took up their attention, and that they found absorbing and enjoyable. So, line up some projects for you and the kids. Chunk up your time so that you can switch activities after an hour or so, make sure you get a bit of body movement in, as well as connecting to people online or over the phone that make you feel good.

“Understand that you have control over your behaviour – even though there’s a lot that feels out of control right now. Stay home. If you need to leave to get food or medicine, plan your trip: how will you stay 2m distant from other people? Where’s your mask? Is your QR code scanning app ready? Is bluetooth switched on? Got your sanitiser? To have the best chance, you need to do all these things, not just some of them when you feel like it.”

No conflict of interest declared.