The pandemic five years on: Lockdowns, vaccine mandates and the lab leak

It was on March 11, 2020, that the World Health Organisation (WHO) declared a global pandemic.

"This is the first pandemic caused by a coronavirus," the WHO said at the time.

Professor Nathan Bartlett, a virologist with Hunter Medical Research Institute, NSW, said lockdowns were a safe choice with unintended consequences.

He said lockdowns, border closures and social distancing affected "the level of community immunity" for a range of viruses and bugs.

"There's a fragile balance between all infectious diseases and society. Any disruption to this balance can have a profound impact," he said.

Professor Bartlett was the first to raise this issue in 2021, attracting global attention.

"These pathogens have now come back and are causing significant diseases. None of that was spoken about at the time," he said.

"I think the equation will be very different in the future. We now understand the negative impacts of lockdowns."

Professor Bartlett highlighted the effects the pandemic had on people's mental health, saying many were left traumatised.

Nonetheless, he said, it should be acknowledged that "the virus kept evolving".

"We were uncertain about what this virus would look like. No one expected this virus would mutate, change and adapt so fast.

"That took the scientific community by surprise. We were dealing with a virus we didn't really understand."

While the origins of the virus remained in doubt, the CIA said last month it was "more likely" to have come from a lab than animals.

Asked if he thought a Wuhan lab leak was the most logical cause of COVID, Professor Bartlett said: "It's difficult to dismiss an accidental lab leak as the origin".

"They were experimenting with coronaviruses that would lead to a human-adapted virus being generated."

On lessons learnt, Professor Bartlett said the pandemic showed "co-operation, sharing of information and resources" were crucial.

"Global co-operation underpinned our ability to get vaccines made and distributed in such a short amount of time," he said.

He recalled that "each state was doing their own thing" in Australia.

"You had the iron curtain in Western Australia," he said.

"Having different responses and messages in different states was confusing.

"It was a complete hodgepodge."

While some felt protected by vaccine mandates, others felt their rights were infringed.

Professor Bartlett underlined that vaccines saved millions of lives and were important for those who needed them, such as older people and those with serious health conditions.

Another key lesson from the pandemic was "the importance of public health infrastructure with disease surveillance".

"We need to be better at keeping track of these viruses," he said.

"We need to get a better handle on what pathogens are doing in our community.

"Unless you're keeping track of them, you won't know what to do or when to respond."

Professor Bartlett said the adoption of telehealth and a new mRNA manufacturing facility were positives to emerge from the pandemic in Australia.