Aussies more vulnerable to flu

Even though Australians’ willingness to roll up their sleeves has been a central feature of the nation’s fight against COVID, the Royal College of Pathologists of Australasia (RCPA) warns that many Aussies are more likely to be vulnerable to influenza this year thanks to vaccine fatigue and low herd immunity.

There was a low uptake of influenza vaccines in 2021, and the threat has been exacerbated thanks to the very low circulation of influenza virus globally over the past two years of the pandemic.

The RCPA recommends anyone aged six months and over to get the influenza vaccine to prevent widespread illness and even deaths from influenza, and those who have not received their COVID vaccine or are eligible for a booster or “winter dose” are encouraged to get both vaccines at the same time.

RCPA Fellow, Dr Jenny Robson, Pathologist-in-Charge of the Department of Microbiology at Sullivan Nicolaides Pathology, said that because influenza activity is particularly difficult to predict this year, people should get vaccinated as soon as possible.

“With the relatively recent opening of international borders, it is highly likely that we will see more influenza cases in Australia in 2022, as measures which protected us from COVID-19 were also effective in reducing the circulation of influenza,” Dr Robson explained.

“This includes the closure of international borders, quarantine for international travellers, and non-pharmaceutical interventions such as wearing masks, hand hygiene, social distancing, working from home and school closures.

“However, we now have lower levels of protection in the community, meaning the virus can spread more quickly… We, therefore, need to increase vaccine coverage in the community, not only to protect ourselves but to protect our vulnerable, just like we have with COVID-19.”

This is particularly important for children aged six months to five years, adults over 65 years, individuals with other illnesses that can make them more susceptible to severe illness, First Nations people and pregnant women.

“In fact, over 65s should also consider Pneumovax, if it is due, which helps to protect against pneumococcal disease,” Dr Robson said.

“All of these vaccines can be administered safely at the same time.”

Just before the pandemic struck in 2019, WA faced its worst flu season on record, with flu cases nearly four times higher (22,720) when compared to 2018 (5,870) and normally, it is estimated that between 5% and 20% of the nation’s population may be infected annually.

Yet in 2021, with lockdowns, mask mandates, social distancing, and sanitisation in full swing, nationally, there were only 598 cases in Australia to date, with no associated deaths – an all-time historic low.

The RCPA hopes it’s not the calm before the storm, noting that while data is limited, studies have found that co-infection with influenza A virus enhances the infectivity of COVID-19.

The peak incidence of influenza usually occurs around July and September; however, this year’s peak could be sooner, with cases of Influenza A already appearing in the community.

The Australian Influenza Vaccine Committee (AIVC) met on the 6th of October 2021 to confirm the Southern Hemisphere 2022 influenza strains and provide advice to the Therapeutic Goods Administration (TGA) on the composition of the seasonal influenza vaccine to be supplied in Australia this year.

Even with high rates of triple-dose protection from the pandemic, it is recommended that quadrivalent vaccines for use in the 2022 Southern Hemisphere influenza season contain the following:

Egg-based vaccines

an A/Victoria/2570/2019 (H1N1)pdm09-like virus;

an A/Darwin/9/2021 (H3N2)-like virus;

a B/Austria/1359417/2021 (B/Victoria lineage)-like virus; and

a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

Cell- or recombinant-based vaccines

an A/Wisconsin/588/2019 (H1N1)pdm09-like virus;

an A/Darwin/6/2021 (H3N2)-like virus;

a B/Austria/1359417/2021 (B/Victoria lineage)-like virus; and

a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.