Australia: Seasonal Flu Vaccine Remains Suspended for young children without risk factors - Advice from the Chief Medical Officer

Australian Government
Department of Health and Ageing
Professor Jim Bishop AO
MD MMed MBBS FRACP FRCPA
Commonwealth Chief Medical Officer
1 June 2010

After consideration of the results to date of a comprehensive investigation into the safety of the seasonal flu vaccine for young children, I have advised, that as a precaution, the suspension of seasonal flu vaccination should continue for healthy children under five years of age.

Since the first reports of a higher than usual occurrence of fever with convulsions in young children following seasonal flu vaccination in WA in April, investigations nationally have confirmed that a small number of children aged under five across the country have experienced fever with convulsions in the 24 hours after vaccination with the 2010 seasonal influenza vaccine. These reactions have been associated mainly with Fluvax, manufactured by CSL.

The investigation conducted by the Therapeutic Goods Administration (TGA), in association with the Australian Technical Advisory Group on Immunisation (ATAGI) and the National Centre for Immunisation Research and Surveillance has identified no apparent clinical, biological or epidemiological factors that would explain the higher than expected observed rates of fever with convulsions. Laboratory testing of the vaccine by the TGA and an audit of the CSL manufacturing plant have also revealed no abnormalities to explain this event. However this investigation is continuing.

Nevertheless, to date, epidemiological analyses point to a rate of febrile convulsions in children aged under five years following 2010 seasonal influenza vaccination of about 9 per 1000 children vaccinated, while the expected rate would be less than 1 per 1000.

While I am recommending that healthy children aged under five years not be vaccinated with seasonal flu vaccine this year, where a child aged under five has medical risk factors that would cause serious health effects for the child if they got the flu, parents should discuss with their doctor whether, on clinical evaluation of the risks and benefits, a seasonal flu vaccination would be the best option.

Doctors should note that, while a higher rate of febrile convulsions has been identified using Fluvax, insufficient doses of this season’s Influvac and Vaxigrip vaccines have been used in children in this age group to accurately determine the rates for these vaccines. In addition, as the cause of the increase in febrile convulsions is not yet known, caution should be exercised.

In addition, the alternative for both healthy children and those with risk factors is the swine flu vaccine, Panvax, which has been shown to be safe and effective in young children and is freely available.

Influenza itself often causes fever in young children which can lead to convulsions and flu vaccine can also produce these side effects but there is a clear signal that the rate of fever with convulsions is higher with this year's vaccine across all jurisdictions.

The investigation found that, while there are some cases of fever with convulsions associated with the swine flu vaccine, these were in line with the expected rate of side effects for a flu vaccine based on the swine flu vaccine clinical trials and experience with seasonal flu vaccines in previous years, both in Australia and internationally.

The TGA will continue to work with overseas Regulators and the US CDC in Atlanta to ascertain the scientific reason for this phenomenon.