Study explores nasal spray flu vaccine effects in children

A new study will explore the effects of a nasal spray flu vaccine on children's immune systems, aiming to boost future protection and lower vaccine hesitancy rates.

The study, led by Murdoch Children's Research Institute (MCRI), involves FluMist, a nasal spray vaccine manufactured by AstraZeneca, as well as the standard, injectable flu shot to better understand a child's immune response to each. Parents can choose which vaccine option they prefer their children to receive.

It's the first study of its kind where some of the samples collected will help the World Health Organization (WHO) formulate flu vaccines and strain selection for children in the Southern Hemisphere.

SNIFFLES  is recruiting 270 children in Victoria, aged two to nine years, who are yet to receive their flu shot. FluMist is approved for safe and effective use in children, aged two to 17 years, by the Therapeutic Goods Administration (TGA).

Project lead MCRI Associate Professor Shidan Tosif said the results would provide valuable new insights into how children develop immunity to influenza vaccines and help boost future protection.

The best way to prevent flu and reduce its impact is to get vaccinated each year. The nasal spray has been safely used for years in countries like the UK and US, but this year is available in Australia for the first time. This has created the perfect opportunity to study immune responses in children after receiving one of the flu vaccines." 

Shidan Tosif, Project Lead, MCRI Associate Professor

Associate Professor Tosif, also a pediatrician at The Royal Children's Hospital, said the nasal spray would likely also make vaccination easier and less distressing for children.

Influenza remains a significant public health issue in Australia, particularly among young children. In 2024, more than 365,000 cases of flu were reported nationwide, the highest number on record, with the majority occurring in children under 10.

Despite the availability of effective vaccines, uptake remains low. In Victoria, only 32 per cent of children aged six months to five years and 15 per cent of those aged five to 15 were vaccinated in 2024.

Additionally, new findings from the 2025 National Vaccination Insights project show a concerning shift in parents' willingness to prioritise influenza vaccination. But the survey found 72.2 per cent of parents agreed a needle-free option would make them more likely to make vaccines a priority. 

Associate Professor Tosif said the findings would also help the WHO formulate flu vaccines for children.

"The study will provide blood samples from Australian children to the WHO helping to fill a gap in global flu monitoring that focuses on those living in the Northern Hemisphere," he said. "These samples will ensure our children's immune responses are considered when flu vaccine strains are chosen, improving vaccine effectiveness in the region and supporting global influenza preparedness."

Danica and George's son Panos, 8, is taking part in the study.

"A lot of young children are needle phobic," Danica said. "Some just can't tolerate a needle, so for those children this nasal spray is going to be a game-changer. Many more children will be vaccinated, meaning a lot less illness will be spreading around the schoolyard. 

"We're always happy to support child health research. As a family, we stay up to date with the flu vaccine, so we're especially keen to help improve the vaccination experience."

The MOVE Consortium in the UK and the WHO Collaborating Centre for Reference and Research on Influenza at The Doherty Institute will analyse the biological samples and data.