If it’s a pandemic, we’re preparing well, says one immunisation expert.
Australia does not yet have the strains of bird flu causing problems in the US and Europe.
But birds fly, people travel and we’re understandably nervous.
The virus has spread from wild birds to poultry, cattle, rats, farm cats, indoor cats and, rarely, humans.
So, are we looking at a pandemic?
“All the elements are there for it to happen. At the moment it hasn’t, and let’s hope that continues,” Dr Gary Grohmann, board member of the Immunisation Coalition and adjunct professor at the University of Sydney, told Allergy & Respiratory Republic.
Australia has not had a homegrown case of avian flu strain – influenza A virus subtype H5N1 clade 2.3.4.4b. – causing so much concern overseas. (The bird flu detected on Victorian poultry farms is H7N8.) And we are keeping an eye out, with a dedicated high pathogenicity avian influenza (HPAI) Preparedness Taskforce coordinating industry, wildlife, health, environmental and scientific activity to stay on top of this biosecurity risk.
“It’s a potentially serious situation, and we just need to keep monitoring, keep preparing, and not panic; neither the farming community nor the community at large,” said Dr Grohmann.
“Even though we’re an island with borders, birds fly and so we can truly expect more bird flu to come to Australia.
“Whether it spills over into humans we’re yet to see but I think we have to anticipate that and do pandemic planning – or epidemic planning at least – for that eventuation, which I think the Department of Health is doing really well. So far, so good.”
A DoHAC spokesperson told ARR that it’s had a “strategic stock of filled and finished pre-pandemic vaccines in the National Medical Stockpile to support the immediate response to the threat of avian influenza H5N1 strain, with enough doses to “support an initial response to a pandemic by vaccinating frontline workers and priority populations” since 2023. Plus, there’s money in the kitty ($22.1 million) to increase this amount as the situation demands.
The Commonwealth has an arrangement with CSL Seqirus for long-term supply and to “scale up its manufacturing operations into full pandemic response mode to allow for more general population level vaccines to be made available – if they are needed,” the spokesperson said.
“Each year, the Commonwealth Department of Health and Aged Care seeks advice from CSL Seqirus, the WHO Collaboration Centre and other experts to inform the selection of the antigen strain to be held in bulk, which can be manufactured into a filled and finished vaccine if required.”
The vaccines in stock are for an H5 strain that is well matched to the global H5N1 2.3.4.4b strain causing concerns,” the spokesperson said.
The stockpile also includes antiviral medicines (oseltamivir and baloxavir) to be used if there is an outbreak, they said.
Finland has been giving the Seqirus vaccine to people at risk – those who work with livestock, laboratory workers, those in contact with the infection – since June 2024, after the outbreak on mink fur farms caused by clade 2.3.4.4b genotype BB resulted in the death of many animals. At the time, there were no cases yet of H5N1 in humans in Finland.
Canada has bought 500,000 doses of the vaccine. The country had its first domestically acquired human case in November. A teenager, now recovered, was made critically ill by the same H5N1 strain found in wild birds and Canadian poultry farms – clade 2.3.4.4b genotype D1.1.
“Highly pathogenic avian influenza A(H5N1) virus infection acquired in North America can cause severe human illness. Evidence for changes to HA that may increase binding to human airway receptors is worrisome,” investigators wrote in a letter to the NEJM.
But Canada has the action right on its doorstep. According to American Medical Association Updates, there are 70 known cases in humans in the USA.
“To put this in perspective, up until now, we had only seen two hospitalisations total in the US. The majority of people who have had confirmed bird flu here have had mild cases, some with conjunctivitis as their only symptom, and have fully recovered,” AMA vice president of Science, Medicine and Public Health, Dr Andrea Garcia, said in the February 19 update.
“Most of the human cases we’ve seen have been the B3.13 genotype, which is thought currently to be less severe for humans, and until recently, it had been the only bird flu genotype that we’ve seen spreading between dairy herds and then also into some nearby poultry farms.”
D1.1, the genotype that infected the Canadian teenager, also killed a Louisiana patient, a man over the age of 65 who was the first to die from an H5 infection.
Recently the CDC released sequencing information from two patients, reported in the 5 March AMA update. One patient, from Wyoming, had the E627K mutation in the PB2 protein.
“That has been linked to efficient replication in people and mammals. And then the Nevada patient, the virus had the D701N mutation in PB2, which has also been linked to more efficient replication in mammals,” Dr Garcia said.
“With that being said, for both of these patients, the CDC didn’t identify any genetic changes in the virus that would impact the efficiency of antiviral medications or the H5 candidate vaccine virus,” said Dr Garcia.
We don’t need to start giving people the bird flu vaccine here just yet, Dr Grohmann said.
At the time of writing, Australia has only had a single case – in a returned traveller in Victoria last year, a two-year-old child with the H5N1 clade 2.3.2.1a, which is different from those causing outbreaks in the US. In our region, a toddler recently died from the H1N1 strain in Cambodia, though the clade was not reported. Cambodia has had 18 cases, half of them fatal, confirmed since early 2023, including from the newer 2.3.4.4b clade.
“The circumstances are a bit different [here],” Dr Grohmann said. “That’s an option [vaccination] the department would have if it got more serious here. In the US that makes some sense, but you don’t want to use a vaccine unnecessarily. You want to have a vaccine and be prepared to use it when you need to.”
The stockpiled seasonal flu vaccine will certainly help, Dr Grohmann said. Although influenza vaccines are not completely matched to viral strains because of the time it takes to manufacture them, they will still save lives, he said.
What will also make a difference is people getting the most recent seasonal flu vaccine.
“The regular flu vaccines will have some cross protection, it would appear, against these viruses. So people should be encouraged to get their influenza vaccines. It almost certainly will have a little bit of effect against one of these other bird flu types. It won’t be dramatic, but it will be some protection.”
It will also stop reassortment of viruses within a human host, in which genes from more than one strain combine in ways that may result in a human-transmissibility advantage.
“A lot of new strains arrive in people that are immunocompromised. So it’s really important to keep up their vaccinations to covid and flu. It may not protect them against the new virus coming in, but it will protect them and the rest of the community from new reassortments arising,” he said.
Only 32% of Australians had the influenza vaccine last year. That’s 500,000 doses fewer than the previous year, and down from 43% in 2022.
“These are good vaccines. They’re freely available, and the more people that are vaccinated, the better,” said Dr Grohmann.
“Every so often, we’re going to get a pandemic. And we’ve seen a pandemic in 2009 we’ve seen the coronavirus pandemic, we’ve seen pandemics in ’47 and ’58. Nineteen-sixty-eight was the H3 pandemic. We’ve seen HIV. We need to understand that there are not two certainties in life, of death and taxes. There are three – death, taxes and pandemics.”
