Authorities hope a new and improved vaccine, plus two new "super vaccines" will help Australia avoid a repeat of last year’s record flu season.
“The new influenza season is unlikely to be anywhere near as bad as the severe season we had last year, which was the biggest on record,” says Professor Robert Booy, director of the Immunisation Coalition – a group part-funded by the companies that make our flu vaccine.
There were almost a quarter of a million confirmed flu infections last year, and more than 29,000 hospitalisations including as many as 1100 deaths.
That was caused by two pieces of bad luck. First, the H3 strain was in high circulation last year, and it is the most dangerous to the elderly. Compounding that, the flu vaccine was particularly ineffective against H3 last year.
The scientists charged with formulating this year's vaccine are confident there will be no repeat performance.
“The vaccines we have this year are improved, they are going to be good – not excellent, but good," says Professor Robert Booy.
“The best expectation I have is we’ll have a mild to moderate season. We don’t have any reason from the northern hemisphere to expect different.”
But making predictions about a virus that is mutating all the time is very difficult indeed.How the flu vaccine works
This year’s standard vaccine will again immunise against four strains of the flu: H1, H3, B-Victoria and B-Yamamata.
H3 was the problem last year, and this year authorities have updated the strain to a 2016 model, which they hope will provide better protection.
Unfortunately, the way the vaccine is manufactured means that is far from guaranteed.
To make a flu vaccine, scientists grow strains of flu in chicken eggs, before extracting, purifying and killing the virus.
These viruses don't like growing in eggs, and often mutate – particularly the H3 strain. Last year, the strain mutated as it grew, and emerged somewhat neutered.
"In eggs, we have this conundrum – the virus has some adaptions to grow in eggs. And sometimes those changes can be unwanted," says Professor Ian Barr, who heads the World Health Organisation's southern hemisphere flu surveillance centre in Melbourne.
That led to the vaccine's effectiveness falling to about 30 per cent last year. It was even less effective in the elderly.
This year, Professor Booy is hopeful of an effectiveness rate of between 30 and 60 per cent. On average, a healthy adult has a 5 to 10 per cent chance of catching the flu each year.Super vaccines The government has also introduced two new "super vaccines". These are needed because of the current vaccine's poor effectiveness in the elderly – who are most at risk. Ninety-one per cent of Australians killed by the flu are over 65.
The first new vaccine is known as Fluad, and it contains an adjuvant – a compound, in this case squalene oil, that increases the immune system's response to the vaccine.
The second vaccine, Fluzone High Dose, has a simpler trick: it has four times the level of inert virus contained within the vaccine.
“The evidence for both these vaccines is you probably get 25 per cent extra protection,” says Professor Booy.
But there is a reason these vaccines have not been introduced to Australia before. They are more potent, but also carry slightly-elevated risks of mild side effects, including muscle and headaches and fatigue.Should I get vaccinated, and when?
Yes, you should get vaccinated – it reduces your chances of getting sick.
The best time to get vaccinated is between mid-April and early May, says the WHO's Professor Barr. So, right now.Source: The Age < Go Back