Fluvax for young put to the test
Some doctors are continuing to inject young children the Fluvax vaccination despite a long-standing ban imposed after it was found to be linked to convulsions.
Official figures show the vaccine was administered to 43 children younger than five years last year, and 31 so far this year despite the ban, which came into force in 2010, a result that Chief Medical Officer Professor Chris Baggoley told AAP “defies belief”.
Professor Baggoley said the cases were a tiny proportion of the more than 48,000 flu jabs given to young children last year, “but for every child that’s been put at risk is makes me profoundly cranky”.
Meanwhile, clinical trials of modifications to bioCSL’s Fluvax vaccine to make it safe to administer to young children are set to begin in August.
The drug manufacturer announced the commencement of trials following the publication of two studies that found the way bioCSL had manufactured Fluvax caused febrile convulsions in several young children who received the vaccine.
Health authorities in 2010 banned the use of Fluvax for children five years or younger, and imposed restrictions on its use for those aged between five and nine years, after it was linked to a significant increase in fever-related convulsions in young children.
The studies, published in the peer-reviewed journal Vaccine, found that the way bioCSL manufactured the vaccine was the root cause of the problem. In particular, they found the virus components contained in the 2010 version of the vaccine combined to overstimulate the immune system of some young children, triggering fever and related convulsions.
The studies also found that these effects could be averted by increasing the levels of virus splitting agents used in the manufacturing process.
bioCSL said it had found that increased levels of virus splitting agents used in making Fluvax had not impaired its function and, following consultations with regulators, this had now been incorporated into its standard method of Fluvax manufacture.
But clinical trials are needed before the use of the vaccine for young children is approved.
“The next step is proving our scientific findings through clinical studies and, until that happens, I want to stress that bioCSL’s Fluvax must not be used in children under five years of age, and that restrictions also remain in place for the use of Fluvax in those aged five to nine years,” bioCSL General Manager Dr John Anderson said.
“We recognise that the events that took place in 2010, and the ongoing uncertainty about the cause, have been very concerning to the public,” Dr Anderson said. “The investigations have been extremely complex, and it is of some relief to have reached this point. Our conclusions now give us a clear path forward, which we intend to pursue to the fullest.”