Estimates of Seasonal Influenza Burden That Could Be Averted by Improved Influenza Vaccines in the Australian Population Aged Under 65 Years, 2015-2019.

BACKGROUND: The interpretation of relative vaccine effectiveness (rVE) of improved influenza vaccines is complex. Estimation of burden averted is useful to contextualise their potential impact across different seasons. For the population aged under 65 years in Australia, this study estimated the additional morbidity and mortality that could be averted using improved influenza vaccines. METHODS: We used observed, season-specific (2015-2019) influenza notification and influenza-coded hospitalisation frequencies and published modelled estimates of influenza-associated hospitalisations and deaths that occurred under the prevailing influenza vaccination coverage scenario. After back-calculating to the estimated burden in the population without vaccination, we applied published standard influenza vaccine effectiveness and coverage estimates to calculate the burden potentially averted by standard and improved influenza vaccines. A plausible range of rVE values were used, assuming 50% coverage. RESULTS: The percentage point difference in absolute vaccine effectiveness (VE) of an improved vaccine compared to a standard vaccine is directly proportional to its rVE and inversely proportional to the effectiveness of the standard vaccine. The incremental burden averted by an improved vaccine is a function of both its difference in absolute VE and the severity of the influenza season. Assuming an rVE of 15% with 50% coverage, the improved vaccine was estimated to additionally avert 1517 to 12,641 influenza notifications, 287 to 1311 influenza-coded hospitalisations and 9 to 33 modelled all-cause influenza deaths per year compared to the standard vaccine. CONCLUSIONS: Improved vaccines can have substantial clinical and population impact, particularly when the effectiveness of standard vaccines is low, and burden is high.

Increased reactions to pediatric influenza vaccination following concomitant pneumococcal vaccination.

BACKGROUND: Influenza in children causes significant morbidity and hospitalizations and also some mortality particularly in children < 5 years of age. Influenza vaccination in children has been shown to be safe and effective, but in 2010 the pediatric influenza vaccination program was suspended in Western Australia after the rate of febrile convulsions observed (9/1000 doses) was 55 times the previously reported rate. In 2009, over 80% of all children in New Brunswick were vaccinated with an adjuvanted monovalent H1N1 vaccine shown to have very high effectiveness, raising the prospect of potential hyper-responsiveness because of residual protection. We conducted enhanced post-marketing surveillance to monitor local and general reactions. METHODS: Parents of participating children seen at dedicated vaccination clinics were given influenza vaccine survey kits to record local and general symptoms up to 3 days following receipt of season influenza vaccine. RESULTS: Febrile reactions of ≥ 38° occurred in <10% of children who received a first dose of seasonal influenza vaccine (n = 660) and severe febrile incidents with fever ≥ 39° were uncommon. Concurrent administration of other vaccine(s) including conjugated pneumococcal vaccine appeared to increase reactogenicity. No child in the study had a febrile convulsion. CONCLUSION: Influenza vaccines in children are safe, and this study provides a baseline for rapid assessment studies at the start of a vaccine season. Parents should be aware of increased fevers with concurrent vaccine administration, and antipyretics should be considered.

Marketing paediatric influenza vaccination: results of a major metropolitan trial.

OBJECTIVES: After a cluster of rapidly fulminant influenza related toddler deaths in a Western Australian metropolis, children aged six to 59 months were offered influenza vaccination in subsequent winters. Some parental resistance was expected and previous poor uptake of paediatric influenza vaccination overseas was noted. A marketing campaign addressing barriers to immunization was developed to maximise uptake. DESIGN: Advertising occurred in major statewide newspapers, via public poster displays and static 'eye-lite' displays, via press releases, via a series of rolling radio advertisements, via direct marketing to child care centres, and via a linked series of web-sites. Parents were subsequently surveyed to assess reasons for vaccination. MAIN OUTCOME RESULTS: The campaign produced influenza vaccination coverage above that previously described elsewhere and led to a proportionate reduction in influenza notifications in this age group compared to previous seasons. CONCLUSIONS: Influenza in children comes with significant morbidity and some mortality. Paediatric influenza vaccination is safe, well tolerated and effective if two doses are given. A targeted media campaign can increase vaccine uptake if it reinforces the seriousness of influenza and addresses community 'myths' about influenza and influenza vaccine. The lessons learned enabling enhancements of similar programs elsewhere.

A prolonged mumps outbreak among highly vaccinated Aboriginal people in the Kimberley region of Western Australia.

OBJECTIVE: To describe a prolonged outbreak of mumps in the Kimberley region of Western Australia in 2007-2008. DESIGN: Descriptive analysis of all mumps cases notified to the WA Notifiable Infectious Diseases Database for the period 1 July 2007 to 30 June 2008. MAIN OUTCOME MEASURES: Notified cases of mumps by patients' place of residence, age, Indigenous or non-Indigenous ethnicity, vaccination status and method of diagnosis. RESULTS: 84% (153/183) of mumps notifications in WA over the study period occurred in the Kimberley region or were directly linked to Kimberley cases. Median age of patients was 18 years (range, 2-63 years), and 54% of patients were aged less than 20 years. Almost all (92%) were Australian Aboriginal people; 67% (102/153) had received at least one dose of mumps vaccine, and 52% had received two doses. The highest notification rate (1816 cases per 100,000 population) was in the Aboriginal 15-19-years age group, and 92% of these patients had received at least one dose of mumps vaccine. Almost all outbreak cases (94%) were laboratory confirmed. Genotyping was performed on 20 mumps virus isolates: all were genotype J. CONCLUSION: A prolonged outbreak of mumps occurred in a well defined, highly vaccinated, predominantly young Aboriginal population in the remote Kimberley region of WA. This outbreak raises questions about the effectiveness and scheduling of the current vaccine (which is genotype A-derived), especially for Aboriginal people. Surveillance of circulating mumps virus genotypes and neutralisation studies will help in evaluating the protection provided by the current vaccine against genotypically different strains.