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It's flu season - the merits of vaccination

Tracy Parish

05 June, 2012

Have you had your flu shot yet?

“We are still unable to predict when the next influenza pandemic will occur” – Emeritus Professor Greg Tannock.

Influenza pandemics involving the introduction of ‘new’ influenza A viruses (most relevant in humans) occur infrequently but have the capacity to cause illness, death and economic loss that dwarf all other human infectious diseases.

Vaccination is the most effective way to prevent illness by influenza viruses that cause the deaths of between 250,000 and 500,000 people globally each year. The uptake of effective and safe vaccines, especially in at-risk individuals, is still less than optimal.

Burnet Senior Fellow and virologist, Emeritus Professor Greg Tannock, believes that we may be at risk of undervaluing the importance of seasonal vaccination.

He has spent more than 30 years researching influenza, one of the most familiar, and still most perplexing, viruses known to man.

Read the full story about his fascinating work in IMPACT.

With a complicated virus like influenza, the solution isn’t as simple as with other highly successful viral vaccines – such as those for the prevention of polio viruses, measles, mumps, rubella and hepatitis B, which remain effective from one year to the next. To be effective against influenza, a new vaccine is required before the onset of each new flu season.

Vaccination: a global effort

Currently, each year, a global process of surveillance forecasting predicts which influenza viruses are likely to cause the most illness in the coming seasons. The process relies on the surveillance and study of disease trends in more than 100 countries, which supply information to the five World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza, one of which is located in Melbourne.

The WHO consults with the directors of these Collaborating Centres twice yearly, and recommendations are made on the composition of the next influenza vaccine. From these recommendations, each individual country makes their own decision as to which strains should be included in influenza vaccines licensed in their country.

The vaccines are then manufactured by a small number of private companies, including CSL Ltd in Melbourne. Influenza vaccines are developed using ‘inactivated’ or killed virus and each season will be effective against one influenza A (H3N2) virus, one seasonal influenza A (H1N1) virus, and one influenza B virus.

Because of the necessity for quick turn-around, manufacturers will often start growing one or more virus strains for the vaccine even before a recommendation is made, based on their own predictions as it usually takes at least six months to produce large quantities of influenza vaccine.

In a normal flu season - where there has not been a pandemic virus – a reasonable match is obtained between the protective ingredients of the vaccine and the viruses responsible for seasonal influenza.

Professor Tannock says that vaccination is a success story and that its cost as the major public health measure for the prevention of influenza is more than justified.

“Many people don’t realise just how effective these vaccines are. Among healthy adults the seasonal vaccination can prevent up to 90 percent of influenza-specific illness,” he said.

“We are also particularly fortunate in Australia to have an influenza vaccine manufacturer (CSL); the only one the Southern Hemisphere and one of very few in the world.”

Professor Tannock says there is still much to learn about influenza and improvements to be made in the development of vaccinations.

“Ideally, we need to develop a vaccine which is effective against both pandemic and non-pandemic viruses which could eliminate most of the ‘bottlenecks’ around vaccine manufacture,” he said.

“Essentially many of the methods developed by virologists more than 60 years ago are still important and relevant to us today; unfortunately, despite all our increased knowledge, we are still unable to predict when the next influenza pandemic will occur.”

Contact Details

For more information in relation to this news article, please contact:

Professor Gregory Tannock

Emeritus Professor, Burnet Institute Visiting Fellow

Telephone

+61385062358

Email

greg.tannock@burnet.edu.au

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