Chief Medical Officer Brendan Murphy has listed closing borders to international travellers, advising federal and state government leaders to shut down non-essential businesses and enforcing hotel quarantine as some of the most pivotal moments in Australia's battle to contain the spread of COVID-19.
Professor Murphy has become a household face and name since March, when he began standing beside the Prime Minister as more and more strict controls were put in place. He said the decision to close the Australian border had been the "single most important", especially as it had gone against what was being advised elsewhere.
"They were done against the conventional mantra," Professor Murphy told the Institute of Public Administration Australia's Work With Purpose podcast.
"WHO has never supported border closures in a pandemic, our colleagues in the UK and Canada, who we were talking with, really questioned and said, 'Why on earth you doing that? It won't help.'"
After the borders were closed and only Australians were returning, professor Murphy said there was evidence 15 per cent of returned travellers were breaking home quarantine rules, making it necessary to introduce hotel quarantine.
I remember driving to work four days after that, driving past a Centrelink office, and seeing the queue and realising the enormity of what we'd done- Brendan Murphy
Professor Murphy also remembers February 1 when he realised the border to China would need to be closed, as case numbers continued to rise outside Wuhan.
"And that probably was one of the most significant things that prevented us getting what happened in Italy, the US, the UK where they had a lot of cases coming from China that spread in the community before they really even knew it," he said.
"So we detected all of the early cases that came out of Wuhan, we had the tests, we had the public health tracing and we isolated them and at no stage have we had large-scale community transmission."
While not many Australians will remember when and where they were when they first heard about coronavirus, Professor Murphy said he first became aware of reports of a Novel Coronavirus in early January when he was on holiday in Rome.
"I remember going on ABC Radio saying 'We're alert but not alarmed'," Professor Murphy said of the early days when it was first believed the virus only moved from animals to humans.
"I was back in Australia then on about the 19th, 20th of January after a week of sort of radio silence from China, we suddenly got new information that there was human-to-human transmission," he said.
"There were many more cases than we thought, that healthcare workers had been infected and there was seriously ill people on ventilators and then our alarm bells started because whilst it was still possible at that stage to contain it in Wuhan.
"Once you have sustained human-to-human transmission, the chances of containment are very much less and we really activated all of our processes from that moment on."
Australia's biggest internal decisions were made at what was to become the last Council of Australian Governments meeting in Parramatta in March, when Prime Minister Scott Morrison moved to limit the number of people at internal gatherings, which led to the shutdown of some industries virtually overnight.
"Over that coming week we closed down not nearly as much as countries like New Zealand, we kept a lot of things going, but we still put a lot of Australians out of work and I remember driving to work four days after that, driving past a Centrelink office, and seeing the queue and realising the enormity of what we'd done," Professor Murphy said.
"It was the right thing to do and we would have had a terrible consequences if we hadn't done it, but I think what we did was timed appropriately.
The visual reminder of just how big the decision had been hit home with Professor Murphy.
"There were people clamouring for us to go harder for longer and for earlier, I think we got it about right but those ... saying to government you need to shut down the entire restaurant, dining, cinemas, clubs, casinos, all of those sort of things, all the people who work in those places, that really weighed on me very heavily."
Despite emphasising Australia had been prepared and had processes in place for a pandemic and structures for the health system to react, Professor Murphy said there was no rule book for understanding a new virus like COVID-19.
"We had a plan, we had a very good pandemic influenza plan, but a pandemic influenza plan is based on the premise that the vaccine will come in three or four months.
"There is no such plan for this virus so we have at all times been taking the best possible guess as we went forward."