FAQs about the new flu vaccines

Professor Allen Cheng tells us what GPs are asking as the new flu season approaches

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GP clinics are already filling their fridges with the two new influenza vaccines for older people in preparation for this year’s flu season.

This is the first year that the Fluzone High-dose vaccine and the Fluad adjuvanted vaccine will be made available free of charge to people aged 65 and over. These vaccines are given as a single dose per flu season.

“We’ve been asked a lot of questions this year,” said Allen Cheng, a professor in infectious disease epidemiology at Monash University. “One of the questions that I get is: ‘How much better are these vaccines going to be?’”

The two new trivalent high dose vaccines are around 24% more effective than the standard quadrivalent flu vaccine.

Fluzone High-dose contains four times the amount of antigen as a standard vaccine, while Fluad contains the adjuvant MF59, which enhances the immune response in older people.

The new vaccines immunise against H1N1, H3N2, and one B strain, but do not include protection against a rarer B influenza strain.

The general consensus was that it was better to give older people enhanced protection against the three most common strains of influenza than to give them weaker protection against all four strains, Professor Cheng said.

“Another question I get is: ‘If someone really doesn’t want flu, should they get both vaccines?’” he said.

Generally, the answer is no, because there is no data to show that two vaccines are better than one.

Some GPs have also asked about giving patients who are younger than 65 the high-dose or adjuvanted vaccines if those patients have immunosuppression or a chronic disease such rheumatoid arthritis.

Again, there wasn’t any evidence to support the use of the higher dose vaccine in people younger than 65 so it was not currently recommended, Professor Cheng said. However, this could change if more studies are conducted in the future.

Another common question is: “Should we vaccinate patients earlier than recommended if we think they are vulnerable and run the risk of the vaccine becoming less effective over the season or is it better to postpone giving the vaccine until closer to the peak flu season?” Due to waning immunity, it is recommended that patients are vaccinated against influenza around May to June instead of earlier in the year.

GPs have to balance the risk of vaccinating too early against the risk that patients will not return for a vaccination at all.

“That is always a really difficult question,” Professor Cheng said.

“In April you’ve always got to ask, are you going to see this patient again before the flu season starts? It’s a case-by-case thing obviously, and you have to make that judgment based on who you’ve got in front of you.”