Viroflu uses the same starting antigen as Enzira, which was recently limited to use in children from 5 years of age following reports of an increased risk of febrile convulsions in children under 5 years. Although Viroflu has a different manufacturing process, an increased risk of febrile convulsions in this age group cannot be ruled out; therefore clinicians are advised to use alternative influenza vaccines. If no suitable alternative is available, parents should be made aware of the risk and given clear advice about the management of post-vaccination fever.
Pandemrix has been linked to cases of narcolepsy in individuals aged 4–19 years in Sweden and Finland. The licence now states that the vaccine may only be used in people aged under 20 years if seasonal trivalent vaccine is not available and if there is a particular need to immunise against H1N1.