Flu vaccines change every year in the strains included based on the previous years prevaence of strains and predicted vectors of transmission through the region.

Whilst the H1N1 is another virus. It is still a flu variant- not new technology- and AUS is a leader in vaccine technology, so I would trust one of our vaccines.

It is reasonable to expect a batch or handling error eg cold storage chain problem given the confinement of febrile illness/ febrile seizures to WA.