Covid 19 coronavirus Australia: No flu deaths this year, but that could change, experts warn

There are 21 new cases of Covid-19 in the community today, bringing the total number of people infected in the outbreak to 72. One million New Zealanders are now fully vaccinated.

Coronavirus restrictions have thrown up double doughnuts of a different kind: no deaths nor hospitalisations in Australia from influenza flu this year.

But a leading medical body warns thousands may die from the disease when international travel resumes.

Lockdowns, wearing masks, social distancing and shutting international borders have contributed to Australia recording 435 positive tests for influenza in 2021.

The latest Australian Department of Health figures showed there had been no deaths nor anyone admitted to hospital since the flu season started in April.

Having zero deaths is in stark contrast to pre-pandemic 2019, when 1080 people succumbed to influenza.

According to the Australian Bureau of Statistics there has not been a death certified due to influenza since late July 2020.

The Australian Bureau of Statistics reports there has not been "a death certified due to influenza since late July 2020". Photo / Getty Images

Immunisation Coalition chair Rod Pearce said it might be the calm before a very dark storm when international travel resumed.

He said there was usually a rebound effect the following year after a low number of influenza deaths because of a decrease in "ongoing herd immunity".

"This year we are nervous," Dr Pearce told NCA NewsWire.

"We won't have the vaccination rates and when we come out of lockdown and get international travel back again. And there's also the paradox, that most people accept, is that it's likely when you have a mild year the ongoing herd immunity is less and there is a rebound year.

"We are in new territory with low numbers, so there is a risk we are going to rebound with flu season so we end up with thousands of deaths from the flu."

He said while there had been a concerted campaign for people to be vaccinated against Covid-19 it was just as important for people to get their yearly flu shot.

After near-record flu vaccinations in 2020, he said the rate of corresponding vaccinations in 2021 had fallen to around 70 per cent and that was of concern.

"When we get out of lockdown, which is going to be towards the end of the year, if people are vaccinated with Covid and are not vaccinated with the flu we will have a couple of issues," Pearce said.

"Will we have different strains? Will the vaccine we are using be for the one [virus] circulating, because we may not be able to match them.

"We had record [flu] vaccine rates and low disease last year and we still have low disease which we are attributing to the lack of international travel, social distancing lockdown and masks."

The was a "rebound" in flu deaths late last decade when 1264 people died from influenza in 2017, which then dipped to 141 in 2018, before another 1000-plus fatalities in 2019.

It all goes to show that, like Covid-19, influenza is an imported disease, said Peter Collignon, an infectious diseases professor at the Australian National University.

"It does appear flu, like Covid, is imported," Collignon said.

Flu vaccinations are down and it a cause for concern say medical experts. Photo / Getty Images

"Other viruses, like the common cold virus, we are seeing in Australia this winter. What's surprising about influenza is how little we have seen.

"So one of the things about influenza is it actually does come in from overseas."

Professor Collignon was not as concerned about an escalating number of flu deaths in 2020 as he remained sceptical about extensive international travel opening up in 2022.

However, he said 2023 could be when a large outbreak of influenza sweeps Australia as he believes international travel will still be heavily restricted for the next 12 months.

"We are not going to have a lot of overseas travellers in the coming winter as there will be restrictions about who comes in and at least some type of home quarantine," he said.

"So, I would be surprised if we saw a lot of influenza next year as we are not going to free unrestricted open borders and it will be from places with low levels of Covid.

"I'd be surprised if there was a surprise big influenza outbreak but 2023 may be different."