As discussed above, there have recently been reports in the Australian and overseas media of an increased risk of febrile convulsions in young children following this season’s flu vaccination. Initially observed in Western Australia in April 2010, the TGA quickly put out a press release advising that they had received 25 reports of spontaneous convulsions following the administration of the vaccine and that WA would be suspending this year’s vaccination program. These figures compared with five reports of convulsions in association with seasonal flu vaccination in 2008 and one in 2009. In response to these figures Australia’s Chief Medical Office, Professor Jim Bishop advised that all GPs and health care providers stop immunisation of children five years and investigations were undertaken and the cause established.
The TGA examined a number of areas to determine a link between the vaccine and febrile convulsions including epidemiological analysis, clinical trial data, manufacturing facilities as well as its own independent testing. The epidemiological studies revealed that the risk of a febrile convulsion following the trivalent seasonal flu vaccination (TIV) was nine per 1000 doses in WA and five per 1000 doses in the rest of the country. This compared to a 0.16/1000 risk of a febrile convulsion 7 days after TIV administration and 0.03/1000 for day 0 during the period 2205-6 to 2009-10. The observed convulsion associated with the 2010 TIV vaccine tended to occur within the first day post administration.
The epidemiological analysis and the fact that no other factor in the areas examined could account for the increased risk, determined that the TGA advised that although the overall risk benefit balance for TIV remained positive further investigation would need to take place.