A fast mutating and highly diverse strain of flu is to blame for the deadly outbreaks in Australian nursing homes, highlighting the need for a better vaccine, says a leading infectious diseases expert.
To date, there have been a record 132,732 laboratory confirmed notifications of influenza in Australia, with several nursing homes residents in Victorian and Tasmania dying as a result of the outbreak.
Professor Allen Cheng at Monash University and Director of Infection Prevention at The Alfred Hospital says a particular subtype of flu circulating this year explains the concerning number of deaths among the elderly.
“The type of flu strain that is circulating this year is [Influenza A] H3 and that tends to affect older people,” Professor Cheng said.
He also said this particular subtype strain is harder to protect against via a vaccine.
There are three types of flu viruses: A, B, and C. H3N2 is a subtype of influenza A.
“The flu virus in general changes from year to year, just enough to affect you again,” said Professor Cheng.
“With H3, for reasons that aren’t entirely clear, it’s more diverse so its hard to find a vaccine that will target all the different types of H3 strains that are out there,” Prof Cheng said.
Health officials say it’s still too early to say if this year’s flu vaccine was ineffective.
“We have to wait and see,” said Professor Ian Barr, deputy director of the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne.
Professor Barr says an interim report card on this year’s vaccine is expected to be released within the next three weeks following a meeting of WHO delegates in Melbourne.
It was confirmed on the weekend that seven people aged between 70 and 94 at St John’s Retirement Village in Wangaratta had died between August 16 and 30 as a result of the outbreak.
The outbreak also killed six residents of a Tasmanian nursing home earlier in August, sparking moves by federal health minister Greg Hunt to make the flu vaccination compulsory among aged care workers.
“We’ll be moving to ensure all health workers in the aged care sector are vaccinated subject to any medical exemptions,” Mr Hunt said on Sunday.
Australian Medical Association President Michael Gannon says the deadly nursing home outbreaks are a ‘wake-up call’ to all Australians to get their flu shot.
The vaccination rate in Australia currently stands at just 20 per cent, according to the latest estimates. That’s about 4.8 million Australians or one out every fifth person.
While its worth getting the flu shot, Professor Cheng says immunisation against the flu only provides a person between 30 to 50 per cent protection.
“That’s not very good. The measles vaccine, for example, is 95 per cent effective,” he said.
“Ultimately we probably need a better (influenza) vaccine that is 100 per cent effective, obviously we haven’t got one yet so it’s not that easy a problem to solve but a lot of people are working on it,” Prof Cheng said.