Australia’s winter illness season is back – what viruses are prevalent this year and when should you get vaccinated?

Australia began the year grappling with an unseasonably high rate of influenza infections, driven by a mutation of the H3N2 strain of the Influenza A virus that emerged in 2025.

While no more severe than other strains, subclade K – which some dubbed “Super-K” because of its infectiousness and subsequent rapid spread – saw thousands of summer flu cases.

The good news is Australia now has an adjusted influenza vaccine that better protects against Super-K.

As winter begins, here’s what you need to know about respiratory illnesses in Australia and the vaccines available.

Annual influenza vaccination is recommended for anyone six months and over. Anyone who received a flu vaccine in late 2025 or early 2026 are encouraged to get another dose, given the vaccine has been updated to protect against currently circulating strains.

Infectious diseases epidemiologist Prof Meru Sheel said: “The best time to get vaccinated is when it’s available in April, but now we’re in June we still really encourage people to get vaccinated.”

What about the Covid vaccine?

Covid-19 and flu vaccines can be given at the same time. Covid-19 vaccination is recommended for those 18 years and older, and for children between six months and 17 years with medical conditions that may increase their risk of severe disease.

“Equally important is for people to watch out for flu-like symptoms and to stay home and social distance if they experience symptoms,” Sheel said.

Is Australia in for a bad flu and Covid season?

Respiratory infections don’t always surge in a predictable way come winter, though in the colder months people often spend more time indoors, making it easier for illnesses to spread. As of June, both influenza and Covid-19 infections remain at low levels in Australia compared to the same time in previous years.

A spokesperson for the Australian Centre for Disease Control said: “How each season will unfold is difficult to predict”.

“Viruses can change over time, people’s immunity and vaccination levels vary, and local conditions – including how people interact – affect how illnesses spread.”

Meanwhile, “Covid-19 doesn’t have a consistent seasonal pattern – numbers fluctuate throughout the year,” the spokesperson said.

What about RSV and who’s eligible for a free vaccine?

As of 4 June, the national notifiable diseases surveillance system has been notified of 33,559 influenza cases, 40,054 Covid-19 cases, and 50,572 cases of RSV, short for respiratory syncytial virus. RSV can cause a chest infection called bronchiolitis, and mostly affects young children.

“RSV trends tend to vary in different areas of Australia,” the CDC spokesperson said. Overall, rates are low compared to the same time in recent years.

The RSV vaccine is available for free to pregnant people, adults aged 75 years and over, and Aboriginal and Torres Strait Islander people aged 60 years and over.

The low numbers of respiratory viruses in winter so far follows the worst influenza season in Australia on record in 2025, which saw more than 500,000 laboratory-confirmed infections. This compares with about 186,000 Covid infections in 2025.

High rates of respiratory illnesses in 2025 were in part driven by the emergence of Super-K, and falling vaccination rates.

Is a needle-free nasal spray flu vaccine available?

Data from between 1 March and 31 May 2026 shows the cohort aged between five and 64 has seen a decline in vaccinations, down to 3.9m from more than 4m in the same period in 2025. However, the same period has seen the highest number of influenza vaccinations given to children under five compared with previous three years.

The deputy director of the World Health Organization’s collaborating centre for reference and research on influenza, Prof Ian Barr, said this may be due to the needle-free flu vaccine for children being made available in 2026.

The nasal spray vaccine is free in WA, South Australia, Queensland and NSW.

When will a combined flu and Covid vaccine be available?

There are several pharmaceutical companies developing combined influenza and Covid vaccines, and in April, the European Commission granted legal approval for a combination vaccine developed by Moderna for people aged 50 and above.

In Australia, any new vaccine needs to be assessed and approved for safety and efficacy by the Therapeutic Goods Administration, then considered and evaluated by independent external experts, before being considered by the Pharmaceutical Benefits Advisory Committee if it is going to be government-funded.

“All those extra steps take time, so whether or not the combined vaccine will be available for next year remains to be seen, and it certainly will not be available this year,” Barr said.