Great vaccine, high jab rates behind fall in flu cases

As we head in to summer, we’re all thinking about the beach, barbecues, and backyard cricket.

Probably the last thing on anyone’s mind is the flu, because we all know that the flu is more common in winter.

Even though catching influenza is far from our thoughts right now, it’s an interesting time to reflect on the winter that has passed.

According to numbers released by the federal government, this year has been an excellent year for the flu.

Or rather, an excellent year for NOT catching the flu. The number of cases of the flu reported this year was down a whopping 80 per cent from last year.

What is responsible for this massive drop? It seems that there was one main thing: vaccination.

The huge decrease in flu cases has coincided with an increasing number of people being vaccinated.

As more people are vaccinated, the virus has a harder time spreading through the population, and outbreaks tend to be smaller. Being vaccinated helps to protect the rest of our community.

It also seems that it was a particularly good vaccine used this year. The influenza vaccine is an interesting one, because unlike other vaccinations against things like measles or hepatitis, it changes each year. It has to, to try and keep pace with the rapidly changing influenza virus. 

Influenza is a tricky thing. It is constantly making small changes to the proteins that sit on its surface. These are the proteins that our immune system recognises, and creates antibodies against.

Each time the virus changes, our old antibodies won’t recognise it, and we have to start the response all over again.

Which is why we can catch the flu over and over – it is the same virus, just slightly different strains.

Each year health authorities have to play psychic, and come up with their best guess as to which strains of the virus are going to be prevalent, and include these in the vaccine.

In Australia, we have a quadrivalent vaccine, so it protects against four different strains. It seems that this year, the powers that be made an excellent call, and the vaccine used provided excellent protection against infection.

So a great vaccine, plus high levels of immunisation, have given us a season with very little flu compared to previous years. It’s been a great example of how well immunisation can help prevent the spread of disease. 

Dr Mary McMillan is a lecturer at the University of New England’s School of Science & Technology.