Influenza and pertussis vaccine coverage in pregnancy in Australia, 2016-2021.

Vaccination in pregnancy is the best strategy to reduce complications from influenza or pertussis infection in infants who are too young to be protected directly from vaccination. Pregnant women are also at risk of influenza complications preventable through antenatal vaccination. Both vaccines are funded under the National Immunisation Program for pregnant women in Australia, but coverage is not routinely reported nationally. We reviewed all reported Australian maternal influenza and pertussis vaccine coverage data for the period 2016-2021, to identify gaps and information needs. Maternal influenza vaccine coverage was suboptimal at < 58% for 2016-2018, with higher coverage of 62-75% reported in two states (Victoria and Western Australia) for 2019-2021. Maternal pertussis vaccine coverage from 2016 was generally higher than for influenza at > 70%, with the highest jurisdictional coverage of 89% reported in Western Australia in 2020. Vaccination rates were often suboptimal among First Nations pregnant women and up to 20% lower than among non-First Nations Australian women; while data were limited, coverage was low among culturally and linguistically diverse women and among women of lower socio-economic status. Jurisdictional perinatal data collections were the best source of information on antenatal vaccine coverage but were only available for a minority of the population; a nationally consistent systematic approach is lacking. Timely and comprehensive data are needed to provide feedback to improve maternal vaccination coverage, particularly among groups with higher risk and/or low uptake, and as new vaccines are recommended, including COVID-19 vaccination.

Risk factors and disease severity in Australian infants aged under 6 months hospitalised with influenza 2011-2019.

AIM: Infants aged <6 months are vulnerable to severe influenza disease and no vaccine is approved for use in this age group. We aimed to describe the epidemiology, risk factors associated with severe outcomes and management of influenza in Australian infants aged <6 months. METHODS: Incident cases aged <6 months of laboratory-confirmed influenza were captured through two national active prospective sentinel hospital-based surveillance systems in Australia from 2011 to 2019, inclusive. Demographic and clinical features, disease risk factors and outcomes (intensive care unit (ICU) admission and length of stay) and oseltamivir use were analysed. The proportion of infant influenza hospitalisations and nosocomial cases among all hospitalisations were also reported. RESULTS: Of 680 hospitalised infants aged <6 months, 57.9% were male and 14.5% were Indigenous Australian. Median age was 2.6 months, 19.2% were born premature and 19.0% had a comorbidity, excluding prematurity. Overall, 77.9% had influenza A. Nosocomial cases accounted for 7.8%. ICU admission occurred in 14.7% and oseltamivir was prescribed for 18.8%. Factors associated with ICU admission included age <1 month (adjusted odds ratio (aOR) 3.95, 95% confidence interval (CI): 1.47-10.60), comorbidity (aOR 7.69, 95% CI: 4.04-14.64) and prematurity (aOR 2.60, 95% CI: 1.40-4.81). The proportion of infants with influenza among all infant hospitalisations ranged 1.0-2.6% in the 2019 influenza season. CONCLUSION: Infants aged <6 months, and particularly neonates, experience serious disease from influenza. This data underpins the need for preventative strategies such as maternal immunisation and continued investigation into the possibility of safe and efficacious vaccination prior to 6 months of age.

Paediatric Active Enhanced Disease Surveillance (PAEDS) annual report 2015: 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). PAEDS data is used to better understand these conditions, inform policy and practice under the National Immunisation Program, and enable rapid public health responses for certain conditions of public health importance. PAEDS enhances data available from other Australian surveillance systems by providing prospective, detailed clinical and laboratory information on children with selected conditions. This is the second of the planned annual PAEDS reporting series, and presents surveillance data for 2015. METHODS: Specialist surveillance nurses screened hospital admissions, emergency department records, laboratory and other data, on a daily basis in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland to identify children with the selected conditions. Standardised protocols and case definitions were used across all sites. Conditions under surveillance in 2015 included acute flaccid paralysis (a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis and varicella-zoster virus infection (varicella and herpes zoster). Most protocols restrict eligibility to hospitalisations, ED only presentations are also included for some conditions. METHODS: : In 2015, there were 674 cases identified across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach WHO reporting targets; identification of signals for Mycoplasma pneumoniae and parechovirus-related outbreaks (ACE surveillance); and demonstration of high influenza activity with vaccine effectiveness (VE) analysis supportive of vaccination. Surveillance for IS remains ongoing with any identified AEFIs reported to the relevant State Health Department; varicella and herpes zoster case numbers decreased slightly from previous years in older children not eligible for catch-up. Pertussis case numbers increased in early 2015 and analysis of cases in children aged <1 year demonstrated the importance of timely childhood and maternal immunisation. CONCLUSIONS: PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

Paediatric Active Enhanced Disease Surveillance inaugural annual report, 2014.

INTRODUCTION: The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment of selected uncommon vaccine preventable diseases and potential adverse events following immunisation (AEFI). PAEDS enhances other Australian surveillance systems by providing prospective detailed clinical and laboratory data for the same child. METHODS: Specialist surveillance nurses screen hospital admissions, emergency department records, laboratory and other data, to prospectively identify hospitalised children aged under 15 years in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland. Standardised protocols and case definitions are used across all sites. Conditions under surveillance include vaccine preventable diseases: acute flaccid paralysis, varicella, pandemic and seasonal influenza and pertussis, and potential AEFIs: febrile seizures and intussusception. PAEDS also conducts surveillance for acute childhood encephalitis. RESULTS: Since August 2007, PAEDS has recruited a total of 6,227 hospitalised cases in total, for all conditions. From January to December 2014, there were 1,220 cases recruited across all conditions. Key outcomes include: enhanced acute flaccid paralysis surveillance to reach World Health Organization targets; supporting varicella and influenza vaccination in children; confirmation of a known low risk of febrile seizures following the 1st dose of measles-mumps-rubella vaccine but no increased risk of febrile seizures after measles-mumps-rubella-varicella vaccine, and a slightly increased risk of developing intussusception 1-7 days after rotavirus vaccination in infants aged less than 3 months. Acute childhood encephalitis data facilitated rapid investigation and response to the enterovirus 71 outbreak in 2013-2014. CONCLUSIONS: PAEDS provides unique policy-relevant data. This is the first of planned PAEDS annual reports to Communicable Diseases Intelligence.

Influenza vaccination among pregnant women in two hospitals in Sydney, NSW: what we can learn from women who decline vaccination.

OBJECTIVE: Pregnant women are recognised as being at risk of serious illness from influenza. Despite this, and longstanding national recommendations for vaccination in pregnancy, vaccine uptake remains suboptimal. This study aims to determine factors associated with women declining influenza vaccination in pregnancy. METHOD: We surveyed pregnant women from antenatal clinics at two Sydney hospitals as part of an evaluation of the New South Wales (NSW) Health 2017 influenza vaccination in pregnancy campaign. Factors associated with a woman's decision to decline influenza vaccination were assessed using Pearson's chi-square test and multivariable logistic regression. RESULTS: Among 642 women surveyed, 58% self-reported influenza vaccination during pregnancy and 19% reported they had declined vaccination. Factors associated with a decision to decline vaccination included lack of a recommendation from a maternity care provider (adjusted odds ratio [aOR] 6.06; 95% confidence interval [CI] 3.50, 10.50), recommendation against vaccination (aOR 4.17; 95% CI 2.07, 8.38), having never previously been vaccinated for influenza (aOR 2.75; 95% CI 1.64, 4.59) and, among third-trimester women, not having been vaccinated for pertussis (aOR 2.55; 95% CI 1.32, 4.89). On univariate analyses, women who declined vaccination were more likely to disagree or feel uncertain about vaccine safety or effectiveness compared with women who chose to be vaccinated. CONCLUSION: Recommendations from maternity care providers remain key to a woman's decision to be vaccinated for influenza during pregnancy. Time should be allocated for vaccine discussions early in pregnancy as part of routine care. Continued efforts are needed to improve messaging to pregnant women on the benefits, safety and efficacy of influenza vaccination.

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.

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.

Paediatric Active Enhanced Disease Surveillance (PAEDS) annual report 2016: 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). PAEDS data is used to better understand these conditions, inform policy and practice under the National Immunisation Program, and enable rapid public health responses for certain conditions of public health importance. PAEDS enhances data available from other Australian surveillance systems by providing prospective, detailed clinical and laboratory information on children with selected conditions. This is the third annual PAEDS report, and presents surveillance data for 2016. Methods: Specialist nurses screened hospital admissions, emergency department records, laboratory and other data, on a daily basis in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland to identify children with the conditions under surveillance. Retrospective data on some conditions was also captured by an additional hospital in the Northern Territory. Standardised protocols and case definitions were used across all sites. Conditions under surveillance in 2016 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. Most protocols restrict eligibility to hospitalisations; Emergency Department (ED) only presentations are also included for some conditions. Results: In 2016, there were 673 cases identified across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach World Health Organization (WHO) reporting targets; identification of the leading infectious causes of acute encephalitis which included human parechovirus, influenza, enteroviruses, Mycoplasma pneumoniae, and bacterial meningo-encephalitis; demonstration of high influenza activity with vaccine effectiveness (VE) analysis demonstrating some protection offered through vaccination. All IS cases associated with vaccine receipt were reported to the relevant state health department. Varicella and herpes zoster case numbers increased from previous years associated with suboptimal vaccination in up to 40% of cases identified. Pertussis surveillance continued in 2016 with the addition of test negative controls captured for estimating vaccine effectiveness. Surveillance for invasive meningococcal disease showed predominance for serotype B in absence of immunisation, and new invasive group A streptococcus surveillance captured severe disease in children. Conclusions: PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.