New data presented today at the Public Health Association of Australia's Communicable Diseases and Immunisation Conference have shown that cell-based influenza vaccines were nearly 20 per cent more effective at preventing test-confirmed infections compared to traditional standard-dose egg-based vaccines.
The presentation is based on data collected during the 2023-24 United States influenza season. It is based on 106,779 vaccinated and influenza-tested patients, aged 6 months to 64 years old.
Findings showed greater protection of cell-based vaccines over standard-dose egg-based vaccines in the prevention of test-confirmed influenza, with an estimated relative vaccine effectiveness of 19.8 per cent for the 2023-24 season.
Relative vaccine effectiveness measures the protection one vaccine type or regimen provides against a particular outcome, in this case, test-confirmed flu, compared to a different type or regimen.
CSL Seqirus said the study results mean that cell-based vaccines have demonstrated greater effectiveness than standard-dose egg-based vaccines in five consecutive seasons, with estimates ranging from 7.7 per cent to 19.8 per cent. This excludes the COVID pandemic period of 2020-21 and 2021-22 when studies were not conducted.
The data has been released as Australia grapples with a significant start to the flu season, with over 104,300 lab-confirmed cases and over 1,396 hospitalisations at sentinel hospitals. This is more than 40 per cent higher than 30 May 2024.
Associate Professor Sheena Sullivan, epidemiologist and study author, said real-world studies are important for helping improve our understanding of different vaccine technologies.
“The frequent mutations in flu viruses mean that flu vaccines have to be updated every year and so it’s not realistic to conduct a randomised controlled trial every year. Trials also often exclude the people most in need of these vaccines,” said Associate Professor Sullivan.
“Real world effectiveness studies, like this one, help us learn how flu vaccines work each season and against different strains of the virus. This study relied on test-confirmed flu cases instead of a diagnosis based on symptoms alone. This helps us understand which study participants contracted the virus so we can get a more specific evaluation of how effective the vaccine is.”
“These types of real-world studies are often conducted overseas as they are difficult to run in Australia, where it’s harder to access and link the large-scale health data needed to compare vaccines like this.”
Cell-based influenza vaccines have been available in Australia since 2021. CSL Seqirus cell-based vaccine, FLUCELVAX QUAD, is approved for people aged 6 months and older and has been listed on the National Immunisation Program (NIP) for eligible medically at-risk individuals aged 5 to 64 since 2024.
Professor Paul Van Buynder, public health physician and GP, said improved vaccines can have a substantial impact on public health.
“Influenza has a significant impact on Australia – both on people’s lives and the healthcare system. Improvements in vaccine effectiveness can significantly reduce that impact, especially when implemented on a large scale,” said Dr Paul Van Buynder.
“A recent Australian study showed that if half of the population under 65 years received an improved flu vaccine with a 20% relative vaccine effectiveness to standard egg-based flu vaccine in 2019, then we could have prevented an additional 16,855 notified cases and prevented 1,749 Australians from ending up in hospital.”
Dr Jules Bayliss, Vaccines Medical Director at CSL Seqirus, said the data highlights the value of innovative vaccine technology in preventing influenza.
“These data further support the use of differentiated, cell-based influenza vaccine technology for all persons over 6 months of age as an effective means of improving influenza protection.
“We will be manufacturing FLUCELVAX QUAD in Australia from next year, when our new cell-based facility comes online in Melbourne.”
The new $800m facility will bolster Australia’s sovereign manufacturing capability and underpins a long-term partnership between the company and the Australian Government for the supply of seasonal and pandemic influenza vaccines, antivenoms and Q fever vaccine.