Epidemiologist Professor Michael Baker says infectious disease is an aspect of environmental degradation, and people have the "social licence" to support governments to take action for the collective good.
In a presentation via Zoom to the Coromandel town of Tairua, he talked of Covid-19's origins, giving residents an insight into a possible laboratory leak from "gain of function" experiments at China's Wuhan Institute of Virology.
Professor Baker has a family connection with Tairua, and was special guest speaker at the book launch of Tairua Locked Down, a compilation book by resident Nola Langford.
Nola's book was presented in time for the anniversary of the lifting of the 2020 lockdown.
Professor Baker said the book showed the positives to come from lockdown - how people came together in solidarity through their communities.
He said the possible leak of Covid-19 from China showed how vital it was to have institutions that can manage risks in the future.
"All of us including myself had dismissed this as almost a conspiracy theory, quite Trumpian in nature, and now the evidence is saying it has moved up to being a viable theory."
The Professor said communities had a role by supporting their governments on environmental protection.
"The world is a highly interconnected place. If we think about environmental degradation, infectious disease is a part of that. We have to act as though we are a global village, we cannot imagine that somehow we're separating ourselves in our gated communities, and that we're not all in it together.
"That means governments making many courageous choices based on evidence. The social licence is the licence we give governments to take action for our collective good and we have to support governments to do that - whatever shade government they are, they have to act.
"It's not about politics, it's about survival and about thriving."
Asked what surprised him the most about responses to the pandemic, he said he was astounded that basic "almost medieval" public health measures worked extremely well and, with effective border controls, could protect New Zealand.
The other was the speed of vaccine development.
The lockdown was imposed when the country had just 100 cases - a "radical departure" from the mainstream strategy against Covid-19 at the time.
Closing the borders, keeping them shut for over a year and reducing travel by 99 per cent would have been laughable in January last year - but New Zealand did it.
He said books such as Nola's, which documented the unique level 4 lockdown experiences of those in the town, showed the social capital of a community and the strength of solidarity in fighting a pandemic.
New Zealand was a world leader with a lockdown that was "about as stringent as it can get for five weeks".
The country has had far less time under lockdown than countries like Sweden, the United States and other OECD countries, which followed a control rather than elimination strategy.
If New Zealand had followed Sweden's strategy, it would have lost about 7000 people by now.
Infectious diseases offer two choices - control or eliminate. Elimination meant keep it out, stamp it out with contract tracing, dampen down transmission with masks and physical distancing, and use vaccination and a social safety net.
He believed there was a reasonable chance that Covid-19 could be progressively eliminated, like measles: "It would even raise the possibility over many years of global eradication. I don't know if this is possible or a good idea yet. But what New Zealand is doing with Australia is a great example to the world at the moment."
Countries pursuing elimination like China, Taiwan, New Zealand and Australia were having vastly fewer deaths than countries in Europe that pursued a lighter touch.
The key last year for New Zealand was the government using lockdown strategically, he said.
If we think about environmental degradation, infectious disease is a part of that and we cannot imagine that somehow we are separating ourselves in our gated communities.
Epidemiologists are "paid to worry", and by the end of January papers were indicating a global pandemic.
"By the end of February there was good news from a World Health Organisation team saying China had stopped this pandemic full flight.
"That was really remarkable and that convinced me that we should go for an elimination approach.
"By mid-March we were seeing the virus was getting established in New Zealand and New Zealand was not ready. So I became a big advocate for the need for a lockdown."
He says most New Zealanders will remember "that amazing speech" when Prime Minister Jacinda Ardern announced the country was going into the highest level of containment fast, with only 100 cases and no deaths.
"All around the Western world people were astounded that New Zealand was doing that, because they were all gradually ramping up their control measures to respond, so this was a very radical departure from the mainstream strategy.
"Interestingly, New Zealand is still probably one of the only countries with an explicit elimination approach."
But by mid-March 2020, New Zealand had "pretty much got the virus from everywhere on the planet".
"We did the modelling for the Ministry of Health and estimated that Covid-19 would kill about 0.3 per cent of the population if it was not stopped, and I think the numbers are confirming that now."
Although the numbers say Covid-19 has killed about 3.5 million, Professor Baker said it's "almost certain" that excess death estimates point to the virus having killed about 10 million people so far.
The pandemic is causing more disease and deaths this year than last year at a global level and it was a pattern that he expected would be seen until at least the end of this year, particularly in low-income countries.
"What does New Zealand have to do? We have to manage our borders very tightly. And these border failures that we have do need to be responded to."
One of the remarkable things is that only one in five virus introductions results in sustained transmission, he said.
"So it's almost like you have a five-sided dice and if it comes down with the wrong number - that one in five - it will create an outbreak.
"That's one reasons why what we see is a product of good management and also good luck. Most of the time you get good luck with some of these cases in the community."
It wasn't just countries with the biggest resources that survived the pandemic and some countries got it horribly wrong. The UK assessment that went down the path of herd immunity had "doomed" their response.
"The Western world didn't learn from Asia, which I think showed a high level of arrogance.
"New Zealand looked towards China and its success and Taiwan, and followed that model in the nick of time. We took a different direction and Australia has caught up. But I think it did cost Australia quite dearly by being less specific in their strategic goal."
Covid-19 continued to throw an endless series of complex questions around public health, equity, social, economic and legal issues that the country is still grappling with a year on from lockdown.
The professor had many surreal moments during the past year, including for him, seeing himself as a character in a play about the pandemic.
He has done many interviews since last year, and was astounded when he was contacted last year by the New York Times seeking comment on the risks of a world-famous politician surviving his Covid-19 infection.
"They said Trump's got it, what's going to happen to him? I was rather amazed that they were ringing me in New Zealand to ask this question. I said well he's 74, he's got a borderline obese BMI ... he'll probably survive based on the risks."
As an epidemiologist who "couldn't resist inflicting graphs on people", he showed a graph of the 1918 flu pandemic.
The1918 flu pandemic killed 9000 people in six weeks in New Zealand, half the number of people who died in the first four years of World War I.
He noted how he'd tried to raise awareness on the centennial of the 1918 flu pandemic in 2018 of the potential disaster of pandemics.
"One of the challenges when you're not having a pandemic is to remind people that we need to keep preparing for them. We need to keep looking at prevention and preparedness."