Fact check: Are your chances of getting the flu after a vaccination only decreased by 1 to 2 per cent?

Woman receiving flu shot

The claim

Australia is well into the midst of winter, and with the cold weather comes flu.

Last year saw the highest levels of flu activity in Australia since the 2009 swine flu pandemic.

This year Australians wanting to be vaccinated against the flu mobilised in unprecedented numbers, forcing the Federal Government to order an additional 800,000 vaccines.

But the effectiveness of the vaccine was called into question by professor of Public Health at Bond University, Chris Del Mar, in an interview with Neil Mitchell on 3AW.

"It actually reduces the chance of getting flu by about 1 to 2 per cent — that's laboratory confirmed influenza. It makes a tiny difference."

So, are your chances of getting the flu after a vaccination only decreased by 1 to 2 per cent? RMIT ABC Fact Check finds out.

The verdict

Professor Del Mar's claim is misleading.

The source of Professor Del Mar's claim is a systematic review of studies measuring the efficacy of flu vaccine in preventing the flu in healthy adults.

That review found the flu vaccine decreased the rate of flu infection from 2.3 per cent to 0.9 per cent in healthy adults.

Experts contacted by Fact Check said while this showed an absolute drop in the infection of 1.4 percentage points, using these numbers to talk about effectiveness was misleading.

Professor Del Mar should instead have talked about the relative drop in infection, which is the effectiveness rate of the vaccine.

The very study quoted by Professor Del Mar found that the flu vaccine had an estimated effectiveness rate of 59 per cent — not 1 to 2 per cent.

That means for an individual who has been vaccinated, the risk of getting the flu is more than halved.

This is supported by other studies cited by the Australian Department of Health's Immunisation Handbook, which found similar effectiveness rates. 

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