Influenza hospitalizations in Australian children.

Australia's National Immunisation Program (NIP) provides free influenza vaccination for children at high risk of severe influenza; a pilot-funded programme for vaccine in all children aged 6 months to <5 years in one of eight states, has seen poor vaccine impact, related to recent vaccine safety concerns. This retrospective review examined influenza hospitalizations in children aged <16 years from three seasons (2011-2013) at two paediatric hospitals on opposite sides of the country. Comparisons of this cohort were made with state-based data on influenza-coded hospitalizations and national immunization register data on population-level immunization coverage. Of 740 hospitalizations, the majority were aged <5 years (476/740, 64%), and a substantial proportion (57%) involved healthy children, not currently funded for influenza vaccine. Intensive care unit admission occurred in 8·5%, and 1·5% of all children developed encephalitis. Use of antiviral therapy was uncommon (20·5%) and decreasing. Of those hospitalized, only 5·0% of at-risk children, who are currently eligible for free vaccine, and 0·7% of healthy children were vaccinated prior to hospitalization. This was consistent with low population-wide estimates of influenza vaccine uptake. It highlights the need to examine alternative strategies, such as universally funded paediatric influenza vaccination, to address disease burden in Australian children.

Systematic review of fever, febrile convulsions and serious adverse events following administration of inactivated trivalent influenza vaccines in children.

In 2010, increased febrile convulsions (FC) occurred after administration of inactivated trivalent influenza vaccine (TIV) in Australia. We systematically reviewed the rates of fever, FC and serious adverse events (SAEs) after TIV, focussing on published and unpublished clinical trial data from 2005 to 2012, and performed meta-analysis of fever rates. From 4,372 records in electronic databases, 18 randomised controlled trials (RCTs), 14 non-randomised clinical trials, six observational studies and 12 registered trials (five RCTs and seven non-randomised) were identified. In published RCTs, fever ≥ 38 °C rates after first dose of non-adjuvanted TIV were 6.7% and 6.9% for children aged 6­35 months and ≥ 3 years, respectively. Analysis of RCTs by vaccine manufacturer showed pooled fever estimates up to 5.1% with Sanofi or GlaxoSmithKline vaccines; bioCSL vaccines were used in two non-randomised clinical trials and one unpublished RCT and were associated with fever in 22.5­37.1% for children aged 6­35 months. In RCTs, FCs occurred at a rate of 1.1 per 1,000 vaccinated children. While most TIVs induced acceptably low fever rates, bioCSL influenza vaccines were associated with much higher rates of fever in young children. Future standardised study methodology and access to individual level data would be illuminating.