The Importance of Flu Vaccination and the Introduction of FluMist
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It’s time to consider getting your flu jab again. Vaccine effectiveness typically peaks one to two months after receiving the shot, and flu season in Australia tends to peak during June and July. Therefore, getting vaccinated now makes sense as it allows your body enough time to build immunity before the peak of the season hits.
This year brings an exciting development: FluMist, the first needle-free influenza vaccine available for children aged between two and 18. This innovation could be a game-changer, especially since Australia has historically struggled with vaccinating children against the flu. Despite children having the highest rates of influenza and often suffering the most when the virus strikes, vaccination rates among them are lower than in adults.
FluMist comes in a small two-dose tube, and the vaccine is sprayed into each nostril, similar to an anti-allergy spray. No need to inhale deeply or hold your nose – it’s a quick and simple process.
In New South Wales, Queensland, and South Australia, FluMist is free for kids under five. However, older children and everyone in Victoria will have to pay $49.95. According to AstraZeneca, about 400,000 doses are available through private pharmacies, and I was able to find doses easily.
How Does FluMist Work?
FluMist isn’t entirely new; it has been available in the United States since 2003 and in Europe since 2011. Australia is only now gaining access because AstraZeneca has developed a version specifically tailored for the southern hemisphere.
This means there is a wealth of data to evaluate. Science relies on a “hierarchy of evidence,” where certain types of evidence are considered more reliable than others. At the bottom are expert opinions, while at the top are meta-analyses, which combine several studies to provide a high-quality estimate.
A 2024 meta-analysis combined 19 randomised-controlled trials (the best-quality type of trial) to compare the effectiveness of FluMist with the standard flu vaccine. To interpret the results, scientists look at a graph called a forest plot, which resembles a “forest of lines.”
Each row represents the results of a single trial comparing FluMist (also known as live-attenuated intranasal vaccine or LAIV) with the standard flu vaccine (injectable influenza vaccine or IIV). The key outcome is the “odds ratio” (OR), which measures the odds of getting a confirmed case of influenza if you received FluMist versus the standard jab.
Three out of six studies found that FluMist offered better protection against the flu, while two found the opposite. The blue polygon at the bottom represents the weighted average of the study findings. By weighting the studies based on precision, the most reliable ones contribute more to the result.
“You’re weighting on precision. A really precise study, even if it’s not that big, will have a really big impact,” explains Dr Gideon Meyerowitz-Katz, a statistics expert at the University of Wollongong.
The weighted average sits almost in the middle, indicating that both vaccines offer similar levels of protection.
“It’s safe and effective, is the bottom line, and there’s real-world experience from the UK for quite a few years now showing it’s a useful vaccine,” says Professor Robert Booy, former head of clinical research at the National Centre for Immunisation Research and Surveillance.
The Science Behind FluMist
Now that we’ve looked at the top-line data, let’s dive deeper into how FluMist works. Unlike the standard flu vaccine, FluMist uses a live version of the virus that is capable of replicating in cells, just like it would during an infection. However, this virus has been weakened so it can only grow in colder environments, such as the inside of the nose.
Immune cells within the mucosal membranes of the nose recognize the virus and generate virus-specific antibodies. These antibodies act as front-line defences, ready to attack the virus when it enters the body. This is a significant advantage over standard flu vaccines, which generate antibodies in the blood rather than at the site of potential infection.
FluMist also has another benefit. Because it contains a live virus, it prompts the body to recruit powerful virus-busting T-cells capable of killing the virus, according to Dr Cyra Patel, who led a review of the evidence for the vaccine for the National Centre for Immunisation Research and Surveillance.
However, there are some trade-offs. FluMist is more likely to cause a runny nose or sniffles compared to the injection-site pain associated with the standard vaccine. Additionally, dealing with a live virus introduces some complexity. In some years, one strain within the vaccine failed to replicate strongly in the nose, leading to reduced protection. As a result, the US temporarily withdrew its recommendation for FluMist for several years after studies showed this issue.
These issues seem to have been resolved, according to Patel. The best evidence suggests that FluMist is every bit as effective as the injectable variant, without the need for needles.
“The data we have shows they are very, very similar in their effectiveness and their safety,” says Patel. “Really, it’s more or less the same.”
