Severe Influenza-Associated Neurological Disease in Australian Children: Seasonal Population-Based Surveillance 2008-2018

BACKGROUND

Influenza-associated neurological disease (IAND) is uncommon but can result in death or neurological morbidity in children. We aimed to describe the incidence, risk factors, and outcome of children with IAND from seasonal influenza in Australia.

METHODS

We analyzed national, population-based, surveillance data for children aged ≤ 14 years with severe influenza and neurological involvement, over 11 Australian influenza seasons, 2008-2018, by the Australian Paediatric Surveillance Unit.

RESULTS

There were 633 laboratory-confirmed cases of severe influenza reported. Of these, 165 (26%) had IAND. The average annual incidence for IAND was 3.39 per million children aged ≤ 14 years. Compared to cases without neurological complications, those with IAND were more likely to have a pre-existing neurological disease (odds ratio [OR] 3.03, P < .001), but most children with IAND did not (n = 135, 82%). Children with IAND were more likely to receive antivirals (OR 1.80, P = .002), require intensive care (OR 1.79, P = .001), require ventilation (OR 1.99; P = .001), and die (OR 2.83, P = .004).

CONCLUSIONS

IAND is a preventable cause of mortality, predominantly in otherwise well children. Incidence estimates validate previous sentinel site estimates from Australia. IAND accounted for a quarter of all severe influenza, is associated with intensive care unit admission, and accounted for half of all influenza deaths.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2019: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is an Australian hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2019.

Methods

Specialist nurses screened hospital admissions, emergency department records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia, to identify children with the conditions under surveillance. Standardised protocols and case definitions were used across all sites. In 2019, the conditions under surveillance comprised: acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal and invasive Group A streptococcus diseases and two new conditions, Kawasaki disease and gram-negative bloodstream infections. An additional social research component continued to evaluate parental attitudes to influenza vaccination.

Results

PAEDS captured 2,701 cases for 2019 across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets for detection of poliomyelitis cases; demonstration of high influenza activity in 2019 and influenza-associated deaths in ACE cases; identification of key barriers to influenza vaccination of children hospitalised for acute respiratory illness; reporting of all IS cases associated with vaccine receipt to relevant state health department; and showing a further reduction nationally in varicella cases. Enhanced pertussis surveillance continued to capture controls to support vaccine efficacy estimation. Invasive meningococcal disease surveillance showed predominance of serotype B and a reduction in cases nationally. Surveillance for invasive group A streptococcus captured severe cases in children. Monitoring of Kawasaki disease incidence and gram-negative bloodstream infections commenced.

Conclusions

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using sentinel hospital-based enhanced surveillance. Keywords: paediatric, surveillance, child, hospital, vaccine preventable diseases, adverse event following immunisation, acute flaccid paralysis, encephalitis, influenza, intussusception, pertussis, varicella zoster virus, meningococcal, group A streptococcus, Kawasaki, bloodstream infections.

Immunisation Coverage Annual Report 2019

Australian Immunisation Register data have been analysed for children aged < 5 years, focusing on changes in vaccination coverage at standard age milestones (12, 24 and 60 months) between 2018 and 2019. ‘Fully vaccinated’ coverage in 2019 increased by 0.1–0.4% at the three age milestones to 94.3% at 12 months, 90.2% at 24 months (in the context of additional antigens required at 24 months) and 94.2% at 60 months. Rotavirus vaccine coverage (2 doses) increased from 90.9% in 2018 to 91.9% in 2019. ‘Fully vaccinated’ coverage in Aboriginal and Torres Strait Islander (hereafter respectfully referred to as Indigenous) children increased by 0.5–1.1% in 2019, reaching 92.9% at 12 months, 88.9% at 24 months and 96.9% at the 60 months (2.7 percentage points higher than in children overall). Recorded influenza vaccination coverage in children aged 6 months to < 5 years increased by 11.4 percentage points to 42.7% in Indigenous children in 2019, and by 15.6 percentage points to 41.8% in children overall. Longstanding issues with timeliness of vaccination in Indigenous children persisted, although the disparity between Indigenous and non-Indigenous children in on-time coverage (within 30 days of due date), for vaccines due at 4 months of age, decreased from 10.4–10.7 to 9.6–9.8 percentage points between 2018 and 2019. The timeliness of ‘fully vaccinated’ coverage was also examined at earlier age milestones (3 months after due date of last scheduled vaccine) of 9, 15, 21 and 51 months, by Indigenous status, socioeconomic status and remoteness of area of residence. Coverage in children living in the least-advantaged residential area quintile was 2.6–2.7% lower than that for those living in the most-advantaged quintile at the 9-, 15- and 21-month milestones, although these disparities were 0.5–1.5 percentage points lower than in 2018. Coverage at the earlier milestones in Indigenous children in remote areas was 1.5–6.7% percentage points lower than that for Indigenous children in major cities and regional areas, although there were some improvements since 2018. Importantly, although Indigenous children had lower coverage for the second dose of measles-mumps-rubella vaccine at 24 months (92.7% versus 93.3% overall), coverage increased to 98.8% at 60 months; coverage was also high overall at 96.4%, above the 95% target critical to measles control. In conclusion, this report demonstrates continuing improvements across a range of immunisation indicators in Australia in 2019. However, some issues with timeliness persist, particularly in Indigenous and socioeconomically disadvantaged children. New coverage targets for earlier protection in the first 2 years of life may be indicated, along with a review of current ‘fully vaccinated’ assessment algorithms, particularly at the 60-month age milestone.

Immunisation Coverage Annual Report 2018

Abstract

Australian Immunisation Register data have been analysed for children aged < 5 years, focusing on changes in coverage at key milestone ages (12, 24 and 60 months) between 2017 and 2018, while also documenting longer term trends. Fully vaccinated coverage increased at the 12- and 60-months milestones to 93.9% and 94.0%, respectively, but, in the context of additional antigens required, decreased to 90.1% at 24 months. Following the move to a two-dose rotavirus vaccine schedule across Australia from mid-2017, rotavirus vaccine coverage increased from 86.8% to 90.9%. In 2018, most jurisdictions funded influenza vaccine for non-Indigenous children aged 6 months to < 5 years; the National Immunisation Program has funded influenza vaccine for Aboriginal and Torres Strait Islander children and medically at-risk children since 2015 and 2010, respectively. Recorded influenza vaccine coverage in Aboriginal and Torres Strait Islander children doubled from 14.9% to 31.4%, and increased fivefold in non-Indigenous children from 5.0% to 25.9% in 2018. The timeliness of fully vaccinated coverage was also examined at earlier milestones (3 months after due date of last scheduled vaccine) of 9, 15, 21 and 51 months, by area of residence. For all children, coverage among those living in the least advantaged residential area quintile was 3-4% lower than that for those in the most advantaged quintile at the 9-, 15- and 21-month milestones. Importantly, although Aboriginal and Torres Strait Islander children had lower coverage for the second dose of measles-mumps-rubella vaccine at 24 months (91.8% versus 93.1% for non-Indigenous), coverage increased to 98.5% at 60 months; coverage was also high in non-Indigenous children at 96.2%, above the 95% target critical to measles control. These data demonstrate continuing improvements in immunisation coverage and suggest potential new coverage targets for earlier protection in the first two years of life.

Immunisation Coverage Annual Report 2019

Abstract

Australian Immunisation Register data have been analysed for children aged < 5 years, focusing on changes in vaccination coverage at standard age milestones (12, 24 and 60 months) between 2018 and 2019. 'Fully vaccinated' coverage in 2019 increased by 0.1-0.4% at the three age milestones to 94.3% at 12 months, 90.2% at 24 months (in the context of additional antigens required at 24 months) and 94.2% at 60 months. Rotavirus vaccine coverage (2 doses) increased from 90.9% in 2018 to 91.9% in 2019. 'Fully vaccinated' coverage in Aboriginal and Torres Strait Islander (hereafter respectfully referred to as Indigenous) children increased by 0.5-1.1% in 2019, reaching 92.9% at 12 months, 88.9% at 24 months and 96.9% at the 60 months (2.7 percentage points higher than in children overall). Recorded influenza vaccination coverage in children aged 6 months to < 5 years increased by 11.4 percentage points to 42.7% in Indigenous children in 2019, and by 15.6 percentage points to 41.8% in children overall. Longstanding issues with timeliness of vaccination in Indigenous children persisted, although the disparity between Indigenous and non-Indigenous children in on-time coverage (within 30 days of due date), for vaccines due at 4 months of age, decreased from 10.4-10.7 to 9.6-9.8 percentage points between 2018 and 2019. The timeliness of 'fully vaccinated' coverage was also examined at earlier age milestones (3 months after due date of last scheduled vaccine) of 9, 15, 21 and 51 months, by Indigenous status, socioeconomic status and remoteness of area of residence. Coverage in children living in the least-advantaged residential area quintile was 2.6-2.7% lower than that for those living in the most-advantaged quintile at the 9-, 15- and 21-month milestones, although these disparities were 0.5-1.5 percentage points lower than in 2018. Coverage at the earlier milestones in Indigenous children in remote areas was 1.5-6.7% percentage points lower than that for Indigenous children in major cities and regional areas, although there were some improvements since 2018. Importantly, although Indigenous children had lower coverage for the second dose of measles-mumps-rubella vaccine at 24 months (92.7% versus 93.3% overall), coverage increased to 98.8% at 60 months; coverage was also high overall at 96.4%, above the 95% target critical to measles control. In conclusion, this report demonstrates continuing improvements across a range of immunisation indicators in Australia in 2019. However, some issues with timeliness persist, particularly in Indigenous and socioeconomically disadvantaged children. New coverage targets for earlier protection in the first 2 years of life may be indicated, along with a review of current 'fully vaccinated' assessment algorithms, particularly at the 60-month age milestone.

Immunisation Coverage Annual Report 2018

Abstract

Australian Immunisation Register data have been analysed for children aged < 5 years, focusing on changes in coverage at key milestone ages (12, 24 and 60 months) between 2017 and 2018, while also documenting longer term trends. Fully vaccinated coverage increased at the 12- and 60-months milestones to 93.9% and 94.0%, respectively, but, in the context of additional antigens required, decreased to 90.1% at 24 months. Following the move to a two-dose rotavirus vaccine schedule across Australia from mid-2017, rotavirus vaccine coverage increased from 86.8% to 90.9%. In 2018, most jurisdictions funded influenza vaccine for non-Indigenous children aged 6 months to < 5 years; the National Immunisation Program has funded influenza vaccine for Aboriginal and Torres Strait Islander children and medically at-risk children since 2015 and 2010, respectively. Recorded influenza vaccine coverage in Aboriginal and Torres Strait Islander children doubled from 14.9% to 31.4%, and increased fivefold in non-Indigenous children from 5.0% to 25.9% in 2018. The timeliness of fully vaccinated coverage was also examined at earlier milestones (3 months after due date of last scheduled vaccine) of 9, 15, 21 and 51 months, by area of residence. For all children, coverage among those living in the least advantaged residential area quintile was 3-4% lower than that for those in the most advantaged quintile at the 9-, 15- and 21-month milestones. Importantly, although Aboriginal and Torres Strait Islander children had lower coverage for the second dose of measles-mumps-rubella vaccine at 24 months (91.8% versus 93.1% for non-Indigenous), coverage increased to 98.5% at 60 months; coverage was also high in non-Indigenous children at 96.2%, above the 95% target critical to measles control. These data demonstrate continuing improvements in immunisation coverage and suggest potential new coverage targets for earlier protection in the first two years of life.

Barriers to influenza vaccination of children hospitalised for acute respiratory illness: A cross-sectional survey

AIM

To identify barriers to influenza vaccination of children hospitalised for acute respiratory illness in Australia.

METHODS

A total of 595 parents of children hospitalised with acute respiratory illness across five tertiary hospitals in 2019 participated in an online survey. Multivariate logistic regression identified factors most strongly associated with influenza vaccination barriers.

RESULTS

Odds of influenza vaccination were lower with lack of health-care provider (HCP) recommendation (adjusted odds ratio (aOR) 0.18; 95% confidence interval (CI): 0.08-0.38); if parents had difficulties (aOR 0.19; 95% CI: 0.08-0.47) or were 'neutral' (aOR 0.23; 95% CI: 0.06-0.82) in remembering to make an appointment; and if parents had difficulties (aOR 0.21; 95% CI: 0.07-0.62) or were 'neutral' (aOR 0.24; 95% CI: 0.07-0.79) regarding getting an appointment for vaccination. Odds were also lower if parents did not believe (aOR 0.27; 95% CI: 0.08-0.90) or were 'neutral' (aOR 0.15; 95% CI: 0.04-0.49) regarding whether the people most important to them would have their child/ren vaccinated against influenza. Children had lower odds of vaccination if parents did not support (aOR 0.09; 95% CI: 0.01-0.82) or were ambivalent (aOR 0.09; 95% CI: 0.01-0.56) in their support for influenza vaccination. Finally, lack of history of influenza vaccination of child (aOR 0.38; 95% CI: 0.18-0.81) and respondent (aOR 0.25; 95% CI: 0.11-0.56) were associated with lack of receipt of influenza vaccine before admission for acute respiratory infection.

CONCLUSIONS

Assisting parents in remembering and accessing influenza vaccination and encouraging health-care providers to recommend vaccination may increase uptake.

Ten Years of National Seasonal Surveillance for Severe Complications of Influenza in Australian Children

BACKGROUND

Severe complications of influenza in children are uncommon but may result in admission to hospital or an intensive care unit (ICU) and death.

METHODS

Active prospective surveillance using the Australian Paediatric Surveillance Unit with monthly reporting by pediatricians of national demographic and clinical data on children with <15 years of age hospitalized with severe complications of laboratory-confirmed influenza during ten influenza seasons 2008-2017.

RESULTS

Of 722 children notified, 613 had laboratory-confirmed influenza and at least one severe complication. Most (60%) were <5 years of age; 10% were <6 months, hence ineligible for vaccination. Almost half of all cases were admitted to ICU and 30 died. Most children were previously healthy: 40.3% had at least one underlying medical condition. Sixty-five different severe complications were reported; pneumonia was the most common, occurring in over half of all cases. Influenza A accounted for 68.6% hospitalizations; however, influenza B was more often associated with acute renal failure (P = 0.014), rhabdomyolysis (P = 0.019), myocarditis (P = 0.015), pericarditis (P = 0.013), and cardiomyopathy (P = 0.035). Children who died were more likely to be older (5-14 years), have underlying medical conditions, be admitted to ICU, and have encephalitis, acute renal failure, or myocarditis. Only 36.1% of all children reported received antiviral medications, and 8.5% were known to be vaccinated for seasonal influenza.

CONCLUSIONS

Severe influenza complications cause morbidity and mortality in children, which may increase if coinfection with COVID-19 occurs in the 2020 season and beyond. Increased vaccination rates, even in healthy children, early diagnosis and timely antiviral treatment are needed to reduce severe complications and death.

Influenza vaccination: A qualitative study of practice level barriers from medical practitioners caring for children with special risk medical conditions

BACKGROUND

Understanding the influenza vaccination practices of general practitioners (GP) and paediatric hospital specialists caring for children with special risk medical conditions (SRMC) is imperative for designing interventions to improve uptake. This study aimed to identify the vaccination decision making, provider practices and perceived barriers and facilitators to recommending or delivering influenza vaccine for children with SRMCs at the tertiary and primary care levels.

METHODS

Nominated GPs and hospital specialists from a single tertiary hospital were interviewed to explore influenza vaccination practices and challenges for children with confirmed SRMCs. Interviews were digitally recorded, transcribed verbatim and thematic analysis was used to inductively code these data. Resulting themes were mapped across the COM-B ('capability', 'opportunity', 'motivation' and 'behaviour') theoretical framework to understanding barriers and potential interventions.

RESULTS

Twenty-six medical practitioners (21 GPs and 5 hospital specialists) completed semi-structured interviews. Barriers, and facilitators for influenza vaccine recommendation (the intended behaviour) were thematically grouped. Opportunity themes included structural barriers (e.g. limited use of systems and processes to support the identification of children with SRMCs); recommendation as standard practice; vaccination inconvenience; lack of communication and educational resources; social acceptance and normalisation; and media messaging. Capability themes included provider communication with parents; knowledge of influenza vaccine recommendations; and professional boundaries to implement the recommendation. Themes in the Motivation category included provider clinical prioritisation and responsibility towards providing a recommendation.

CONCLUSIONS

The main barriers to influenza recommendation raised by our study participants were structural. These included lack of processes to identify children with SRMCs, limited use of reminder systems and unclear delineation of role responsibility between hospital specialists and GPs. An important driver that emerged was GPs' responsibility for providing a recommendation. To increase influenza vaccine coverage for children with SRMCs, consideration should be given to addressing practice level structural barriers and improving collaboration.

Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2019

The Australian Paediatric Surveillance Unit (APSU) has been prospectively collecting national data on rare childhood conditions since 1993, with monthly reporting of cases by paediatricians. In this report we describe annual results from studies for ten communicable diseases and complications of communicable diseases that were conducted using APSU surveillance in 2019 and place these in an historic context. Results are reported on acute flaccid paralysis, congenital cytomegalovirus infection, neonatal herpes simplex virus infection, perinatal exposure to HIV, paediatric HIV infection, severe complications of seasonal influenza, juvenile onset recurrent respiratory papillomatosis (JoRRP), congenital rubella syndrome, congenital varicella syndrome and neonatal varicella infection. APSU provides rich clinical data to complement data collected from other surveillance systems and to improve understanding and response to rare childhood infections.

Identifying early changes in influenza vaccination uptake following a government funded immunisation program using a participatory community surveillance program

Following Australia’s severe influenza season in 2017, the health departments of the states and territories commenced funding in 2018 of influenza vaccine for all children aged six months to five years. As the national immunisation register has recently been extended to include recording of vaccination for all age groups, Australia’s community-based influenza-like illness (ILI) surveillance system, Flutracking, was used to explore influenza vaccine coverage in participants. Flutracking participants respond to a weekly survey about ILI from April to October each year. Participants report their influenza vaccine status with the current year’s vaccine in the first weekly survey, and if unvaccinated (or unknown), participants are prompted with the question weekly until the end of the Flutracking season. Detailed methods for Flutracking are available elsewhere.1 Self-reported vaccine coverage by age group (<5 years, 5 to 17 years, 18 to 64 years and ≥65 years) was calculated at 21 October (timing of the final 2018 Flutracking survey) for participants who had completed at least one survey in 2018. The five-year average was calculated for the percentage vaccinated at the end of the Flutracking survey for the years 2013 to 2017, and compared to 2018. Flutracking received ethics approval from the University of Newcastle (# 06/03/22.403) in 2006. In 2009 the program applied to the University of Newcastle to exit the ethics committee review as Flutracking had been incorporated into the national influenza surveillance system. The total number of participants completing at least one survey increased from 18,437 in 2013 to 45,532 in 2018. Flutracking participants are more likely to be female (59.8% compared to 50.4%) and more likely to have completed a postgraduate degree (22.6% compared to 3.6%) than the general Australian population.2 A relatively large proportion of Flutracking participants are health care workers, working face to face with patients (17.5%). Keywords: flutracking, vaccine coverage, influenza vaccine, influenza like illness, community based surveillance

Active surveillance of acute paediatric hospitalisations demonstrates the impact of vaccination programmes and informs vaccine policy in Canada and Australia

Sentinel surveillance of acute hospitalisations in response to infectious disease emergencies such as the 2009 influenza A(H1N1)pdm09 pandemic is well described, but recognition of its potential to supplement routine public health surveillance and provide scalability for emergency responses has been limited. We summarise the achievements of two national paediatric hospital surveillance networks relevant to vaccine programmes and emerging infectious diseases in Canada (Canadian Immunization Monitoring Program Active; IMPACT from 1991) and Australia (Paediatric Active Enhanced Disease Surveillance; PAEDS from 2007) and discuss opportunities and challenges in applying their model to other contexts. Both networks were established to enhance capacity to measure vaccine preventable disease burden, vaccine programme impact, and safety, with their scope occasionally being increased with emerging infectious diseases’ surveillance. Their active surveillance has increased data accuracy and utility for syndromic conditions (e.g. encephalitis), pathogen-specific diseases (e.g. pertussis, rotavirus, influenza), and adverse events following immunisation (e.g. febrile seizure), enabled correlation of biological specimens with clinical context and supported responses to emerging infections (e.g. pandemic influenza, parechovirus, COVID-19). The demonstrated long-term value of continuous, rather than incident-related, operation of these networks in strengthening routine surveillance, bridging research gaps, and providing scalable public health response, supports their applicability to other countries.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2017 and 2018: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine-preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2017 and 2018.

Methods

Specialist nurses screened hospital admissions, emergency department (ED) records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia to identify children with the conditions under surveillance. In 2017 and 2018 these included acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal, and invasive Group A streptococcus diseases. An additional social research component was added to evaluate parental attitudes to vaccination.

Results

PAEDS captured 1,580 and 925 cases for 2017 and 2018, respectively, across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets; identification of a third human parechovirus outbreak among other infectious diseases linked to ACE; demonstration of variable influenza activity between 2017 and 2018, with vaccine effectiveness (VE) analysis demonstrating that the protection offered through vaccination is season-dependent. All IS cases associated with vaccine receipt were reported to the relevant state health department. Varicella and herpes zoster case numbers remained unchanged, with vaccine uptake found to be suboptimal among eligible children under the NIP. Enhanced pertussis surveillance continues to capture controls for VE estimation. Surveillance for invasive meningococcal disease showed predominance for serotype B at 57% over 2 years among 77 cases where serotyping was available, and surveillance for invasive group A streptococcus captured severe disease in children.

Conclusion

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

Disparities in parental awareness of children's seasonal influenza vaccination recommendations and influencers of vaccination

Objective

To determine parental awareness of influenza vaccination recommendations for children and explore associations with awareness.

Design

Cross-sectional survey.

Setting/participants

South Australian parents with a telephone listing in the Electronic White Pages were randomly selected.

Methods

Participants were interviewed using Computer Assisted Telephone Interviewing (CATI) during May–July 2016. Univariable and multivariable analyses explored characteristics associated with awareness; with the survey data weighted to reflect the population of SA and the probability of selection within a household.

Results

Of 539 parents, 33% were aware of the recommendation that all children (<5 years) should receive the influenza vaccine annually with 51.9% aware that children with special risk medical conditions (SRMC) should also receive the vaccine annually. Characteristics strongly associated with parental awareness of the recommendation for children aged < 5 years were knowledge of recommendation for children with a SRMC (adjusted Odds Ratio [aOR] 10.46, CI 4.44–24.63) or living in a metropolitan area (aOR 2.91, CI 1.19–7.09). There was lack of awareness in those not working (aOR 0.13, CI 0.04–0.47), with trade level education (compared with high school) (aOR 0.25 CI, 0.09–0.71) and in those born in the UK or Ireland (aOR 0.19, CI 0.04–0.85). Awareness of the recommendation for children with SRMC to receive the vaccine was strongly associated with knowledge of the influenza recommendation for children <5 years (aOR 10.22, CI 4.39–23.77) or not being born in Australia [UK/ Ireland (aOR 7.63, CI 1.86–31.31); other (aOR 3.93, CI 0.94–16.42)]. The most influential cues to future receipt were a general practitioner (GP) recommendation (63.8%) and providing influenza vaccine free for all children (37.6%). More parents who delayed or excluded vaccines believed that their children’s vaccinations (in general) were unnecessary, as other children were vaccinated (42.8%) compared to those with no or minor concerns (11.1%) (p<0.0001).

Conclusions

Parental awareness of children’s influenza vaccine recommendations is low. Targeted communication strategies and resources are required to establish broader community awareness of recommendations. Healthcare provider endorsement of the vaccine remains key and health care professionals, particularly GPs and paediatric specialists should be encouraged to discuss influenza vaccine with parents at every opportunity. Many parents have vaccine concerns and addressing concerns across the spectrum of hesitancy is crucial.

The impact of new universal child influenza programs in Australia: Vaccine coverage, effectiveness and disease epidemiology in hospitalised children in 2018

BACKGROUND

New jurisdictionally-based vaccination programs were established providing free quadrivalent influenza vaccine (QIV) for preschool Australian children in 2018. This was in addition to the National Immunisation Program (NIP) funded QIV for Indigenous children and children with comorbid medical conditions. We assessed the impact of this policy change on influenza disease burden and vaccine coverage, as well as report on 2018 vaccine effectiveness in a hospital-based surveillance system.

METHODS

Subjects were recruited prospectively from twelve PAEDS-FluCAN sentinel hospital sites (April until October 2018). Children aged ≤16 years hospitalised with an acute respiratory illness (ARI) and laboratory-confirmed influenza were considered cases. Hospitalised children with ARI who tested negative for influenza were considered controls. VE estimates were calculated from the adjusted odds ratio of vaccination in cases and controls.

RESULTS

A total of 458 children were hospitalised with influenza: 31.7% were <2 years, 5.0% were Indigenous, and 40.6% had medical comorbidities predisposing to severe influenza. Influenza A was detected in 90.6% of children (A/H1N1: 38.0%; A/H3N2: 3.1%; A/unsubtyped 48.6%). The median length of stay was 2 days (IQR: 1,3) and 8.1% were admitted to ICU. Oseltamivir use was infrequent (16.6%). Two in-hospital deaths occurred (0.45%). 12.0% of influenza cases were vaccinated compared with 36.0% of test-negative controls. Vaccine effectiveness of QIV for preventing influenza hospitalisation was estimated at 78.8% (95%CI: 66.9; 86.4).

CONCLUSIONS

Compared with 2017 (n = 1268 cases), a significant reduction in severe influenza was observed in Australian children, possibly contributed to by improved vaccine coverage and high vaccine effectiveness. Despite introduction of jurisdictionally-funded preschool programs and NIP-funded vaccine for children with risk factors for severe disease, improved coverage is required to ensure adequate protection against paediatric influenza morbidity and mortality.

Early signal detection of adverse events following influenza vaccination using proportional reporting ratio, Victoria, Australia

INTRODUCTION

Timely adverse event following immunisation (AEFI) signal event detection is essential to minimise further vaccinees receiving unsafe vaccines. We explored the proportional reporting ratio (PRR) ability to detect two known signal events with influenza vaccines with the aim of providing a model for prospective routine signal detection and improving vaccine safety surveillance in Australia.

METHODS

Passive AEFI surveillance reports from 2008-2017 relating to influenza vaccines were accessed from the Australian SAEFVIC (Victoria) database. Proportional reporting ratios were calculated for two vaccine-event categories; fever and allergic AEFI. Signal detection sensitivity for two known signal events were determined using weekly data; cumulative data by individual year and; cumulative for all previous years. Signal event thresholds of PRR ≥2 and Chi-square ≥4 were applied.

RESULTS

PRR provided sensitive signal detection when calculated cumulatively by individual year or by all previous years. Known signal events were detected 15 and 11 days earlier than traditional methods used at the time of the actual events.

CONCLUSION

Utilising a single jurisdiction's data, PRR improved vaccine pharmacovigilance and showed the potential to detect important safety signals much earlier than previously. It has potential to maximise immunisation safety in Australia. This study progresses the necessary work to establish national cohesion for passive surveillance signal detection and strengthen routine Australian vaccine pharmacovigilance.

Attitudes about and access to influenza vaccination experienced by parents of children hospitalised for influenza in Australia

INTRODUCTION

In Australia, influenza hospitalises more children than any other vaccine preventable disease does. Children aged six months or older are recommended to receive annual influenza vaccines, and pregnant women are recommended vaccination to protect infants aged up to six months. However, vaccine uptake is low. This study explored influenza vaccination knowledge and behaviours of parents of children who were hospitalised for influenza, in order to inform strategies that target barriers to uptake.

METHODS

We conducted 27 semi-structured interviews with parents/caregivers during or shortly after their child's hospitalisation for laboratory-confirmed influenza in 2017. Questions were guided by the Social Ecological Model exploring all levels of influence on vaccination uptake from the intrapersonal through to policy, via the parents' perspective. Transcripts were inductively analysed. Themes were categorised into the components of the Capability-Opportunity-Motivation-Behaviour (COM-B) model.

RESULTS

20/27 children were aged six months or older; 16/20 had not received an influenza vaccine in 2017. Mothers of 4/7 infants aged less than six months were not vaccinated in pregnancy. The themes regarding barriers to influenza vaccination were: (1) Limited Capability - misinterpretations and knowledge gaps, (2) Lack of Opportunity - inconvenient vaccination pathway, missing recommendations, absence of promotion to all, and the social norm, and (3) Missing Motivation - hierarchy of perceived seriousness, safety concerns, a preference for 'natural' ways. Though most parents, now aware of the severity of influenza, intended to vaccinate their child in future seasons, some harboured reservations about necessity and safety. When parents were asked how to help them vaccinate their children, SMS reminders and information campaigns delivered through social media, schools and childcare were suggested.

CONCLUSION

Improving parents' and providers' knowledge and confidence in influenza vaccination safety, efficacy, and benefits should be prioritised. This, together with making influenza vaccination more convenient for parents, would likely raise vaccine coverage.