Federal flu vaccine boost to deliver free, stronger shots for over-65s

Two new, stronger flu vaccines will be available to older Australians for free this season in a bid to prevent another deadly outbreak.

More than 1100 people across Australia died from the flu last year, with most of them over 65.

FluAd and FluZone will be free for over 65s when the supply arrives in Australia in April, the federal government announced today.

"The two new vaccines are about giving Australians the best chance at getting through the flu season with as little impact as possible," Health Minister Greg Hunt told reporters in Melbourne.

Last year's flu season was deadly because the elderly immune response to the vaccine had been waning in recent years and the A-strain of the flu mutated mid-season, leaving even vaccinated people vulnerable, Chief Medical Officer Brendan Murphy said.

"That was an unusual shift and it's being analysed very closely by the world health organisation," Prof. Murphy told reporters.

The new vaccines were aimed at improving the response in elderly people in two ways.

"One of them has more of the killed-virus antigen in it, that produces a stronger immune response, and the other one has a standard amount of the antigen but has ... a chemical which tickles up the immune system to respond better," Prof. Murphy said.

The new vaccine contains four times the amount of antigen, or active ingredient, for each of the three strains in the vaccine, compared with regular influenza vaccines.