THE Australian-made flu vaccine Fluvax, has been identified as being the most likely trigger of 59 convulsions in Western Australia and in about 20 cases elsewhere, including four in NSW and six in Victoria. All the babies, most of them under two years, recovered fully.

Fluvax found to trigger a nine times higher than the expected rate of convulsions in babies, will remain available for use but subject to precautionary measures.

Despite investigations in the past month, experts have not identified a reason for the higher rate of convulsions. These occurred in nine out of every 1000 children vaccinated, when the expected rate was fewer than one in 1000.

CSL is also being required to declare the increased convulsion risk in patient information leaflets distributed with Fluvax.

The Commonwealth's chief medical officer, Jim Bishop, said yesterday the suspension of seasonal flu vaccinations for healthy children aged under five would continue.

Professor Bishop said that where infants were at risk of respiratory diseases such as asthma, and an influenza shot was advisable, parents should discuss with their doctor whether a seasonal flu vaccination would be the best option.

He urged caution in the use of Fluvax for the under-fives and said the other two seasonal flu vaccines available, Influvac and Vaxigrip, were not yet completely in the clear because of lower use in Australia.

An alternative for both healthy children and those at risk of other diseases was the swine flu vaccine, Panvax, which has been shown to be safe, he said.

Fluvax contains elements designed to protect against two strains of seasonal flu and also against swine flu. The reason why this combination triggers convulsions is not yet known.