Influenza epidemiology, vaccine coverage and vaccine effectiveness in children admitted to sentinel Australian hospitals in 2014: The influenza complications alert network (FluCAN)

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance programme operating in all states and territories in Australia. We summarise the epidemiology of children hospitalised with laboratory-confirmed influenza in 2014 and reports on the effectiveness of inactivated trivalent inactivated vaccine (TIV) in children. In this observational study, cases were defined as children admitted with acute respiratory illness (ARI) with influenza confirmed by PCR. Controls were hospitalised children with ARI testing negative for influenza. Vaccine effectiveness (VE) was estimated as 1 minus the odds ratio of vaccination in influenza positive cases compared with test-negative controls using conditional logistic regression models. From April until October 2014, 402 children were admitted with PCR-confirmed influenza. Of these, 28% were aged < 1 year, 16% were Indigenous, and 39% had underlying conditions predisposing to severe influenza. Influenza A was detected in 90% of cases of influenza; influenza A(H1N1)pdm09 was the most frequent subtype (109/141 of subtyped cases) followed by A(H3N2) (32/141). Only 15% of children with influenza received antiviral therapy. The adjusted VE of one or more doses of TIV for preventing hospitalised influenza was estimated at 55.5% (95% confidence intervals (CI): 11.6–77.6%). Effectiveness against influenza A(H1N1)pdm09 was high (91.6%, 95% CI: 36.0–98.9%) yet appeared poor against H3N2. In summary, the 2014 southern hemisphere TIV was moderately effective against severe influenza in children. Significant VE was observed against influenza A(H1N1)pdm0

Epidemiological characteristics of varicella from 2000 to 2008 and the impact of nationwide immunization in Taiwan

[[abstract]]Background: Varicella has an important impact on public health. Starting in 2004 in Taiwan, nationwide free varicella vaccinations were given to 1-year-old children.Methods: Our study investigated the epidemiological characteristics of varicella from 2000 to 2008, and assessed the change of varicella epidemiology after the mass varicella immunization. ICD-9-CM codes related to varicella or chickenpox (052, 052.1, 052.2, 052.7, 052.8, 052.9) were analyzed for all young people under 20 years of age through the National Health Insurance database of Taiwan from 2000 to 2008.Results: Case numbers of varicella or chickenpox significantly declined after the nationwide immunization in 2004. Winter, particularly January, was the epidemic season of varicella. We found a significant post-vaccination decrease in incidence among preschool children, especially 3 to 6 year-old children-- the peak incidence was 66 per thousand for 4 and 5 year-old children before the nationwide immunization (2000 to 2003), and the peak incidence was 23 per thousand for 6 year-old children in 2008 (p < 0.001). Varicella-related hospitalization also significantly decreased in children younger than 6 years after the nationwide immunization.Conclusion: The varicella annual incidence and varicella-related hospitalization markedly declined in preschool children after nationwide varicella immunization in 2004

Evolutionary analysis of human parechovirus type 3 and clinical outcomes of infection during the 2017-18 Australian epidemic.

Human parechovirus type 3 (HPeV3) can cause severe sepsis-like illness in young infants and may be associated with long term neurodevelopmental delay later in childhood. We investigated the molecular epidemiology of HPeV infection in thirty three infants requiring hospitalization before, during and after the peak of the 2017/18 HPeV epidemic wave in Australia. During the peak of the epidemic, all cases were infected with an HPeV3, while before and after the peak, HPeV1 was the predominant type detected. The predominant HPeV3 was the recombinant HPeV3 also detected in the 2013/14 and 2015/16 Australian epidemics. Sepsis-like or meningitis-like symptoms were only reported in cases infected with the recombinant HPeV3. Phylogenetic analysis of the recombinant HPeV3 revealed that the virus continued to evolve, also between the Australian outbreaks, thus indicating continued circulation, despite not being detected and reported in Australia or elsewhere in between epidemic waves. The recombinant HPeV3 continued to show a remarkable stability in its capsid amino acid sequence, further strengthening our previous argument for development of a vaccine or immunotherapeutics to reduce the severity of HPeV3 outbreaks due to this virus

ATAGI 2021 annual statement on immunisation Last updated: 19 September 2021.

The Australian Technical Advisory Group on Immunisation (ATAGI) 2021 Annual Statement on Immunisation is the first publication in this series. It highlights the key successes, trends and challenges in the use of vaccines and control of vaccine preventable diseases (VPDs) in Australia in 2020. It also signals ATAGI’s priority actions for addressing key issues for 2021 and beyond

Australian hospital paediatricians and nurses' perspectives and practices for influenza vaccine delivery in children with medical comorbidities

INTRODUCTION: Influenza vaccination of children with medical comorbidities is critical due their increased risks for severe influenza disease. In Australia, hospitals are an avenue for influenza vaccine delivery to children with comorbidities but are not always effectively utilised. Qualitative enquiry sought to ascertainment the barriers and enablers for influenza vaccination recommendation, delivery, and recording of these children at Australian hospitals. METHODS: Semi-structured interviews and discussion group sessions were conducted with paediatricians and nurses at four tertiary paediatric specialist hospitals and two general community hospitals in three Australian states. Transcripts from interviews and group sessions were inductively analysed for themes. The Capability, Opportunity, Motivation, and Behaviour (COM-B) model was used to explore the elements of each theme and identify potential interventions to increase influenza vaccination recommendation and delivery behaviours by providers. RESULTS: Fifteen discussion sessions with 28 paediatricians and 26 nurses, and nine in-depth interviews (five paediatricians and four nurses) were conducted. Two central thematic domains were identified: 1. The interaction between hospital staff and parents/patients for influenza vaccine recommendation, and 2. Vaccination delivery and recording in the hospital environment. Six themes across these domains emerged detailing the importance of dedicated immunisation services, hospital leadership, paediatricians' vaccine recommendation role, the impact of comorbidities, vaccination recording, and cocooning vaccinations. Supportive hospital leadership, engaged providers, and dedicated immunisation services were identified as essential for influenza vaccination of children with comorbidities in Australian hospital. CONCLUSION: Recommendation of influenza vaccination for Australian children with comorbidities is impacted by the beliefs of paediatricians and the perceived impact of influenza disease on children's comorbidities. Dedicated immunisation services and supportive hospital leadership were drivers for influenza vaccine delivery at hospitals. Future interventions targeting hospital-based influenza vaccine delivery for children with comorbidities should take a rounded approach targeting providers' attitudes, the hospital environment and leadership support

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

Australian rubella serosurvey 2012–2013: On track for elimination?

Background: The World Health Organization has targeted rubella virus for elimination regionally. Australia was one of the first countries to implement a nationally funded rubella immunisation program, in 1971, and conducts regular national rubella serosurveillance studies. We aimed to estimate the seroprevalence of rubella-specific IgG antibody in the Australian population by age and sex in 2012–2013, to compare the results with three previous serosurveys conducted in 1996–1999, 2002 and 2007 and to estimate the effective reproduction numbers (Rn). Methods: This study used 2729 serum and plasma specimens, randomly selected from a specimen bank collected in 2012–2013 across Australia. Age groups included in the sample ranged from 1 to 49 years. Sera were tested for rubella-specific IgG-antibody using the Enzygnost anti-rubella IgG enzyme immunoassay and classified as positive, negative or equivocal according to rubella-specific IgG concentrations of >7 IU/ml, <3 IU/ml and 3–7 IU/ml, respectively. Results: The overall proportions seropositive, seronegative and equivocal for rubella-specific IgG were 92.1% (95% CI, 91.0–93.2), 6.7% (95% CI, 5.7–7.7) and 1.2% (95% CI, 0.8–1.6), respectively. The proportion of males seropositive was significantly lower than females in the 30–34 (83.1% vs. 96.8%, p = 0.003), 35–39 (86.1% vs. 96.3%, p = 0.02) and 40–44 (86.1% vs. 95.7%, p = 0.03) year age groups. Rn for rubella in 2012–2013 was estimated to be 0.33 (95% CI 0.28–0.39). Discussion: The 2012–2013 national serosurvey showed levels of rubella-specific IgG seropositivity in the Australian population are relatively high with no evidence of decrease compared to previous serosurveys conducted in 1996–1999, 2002 and 2007. The lower proportion of seropositive males aged 30–44 years likely reflects the initial immunisation program targeting females only. To our knowledge this study represents the longest period of serosurveillance following introduction of a nationally funded rubella immunisation program. The lack of evidence of decreasing rubella-specific IgG seropositivity is therefore reassuring for Australia and other countries with longstanding high vaccine coverage

Influenza hospitalizations in Australian children 2010-2019: The impact of medical comorbidities on outcomes, vaccine coverage, and effectiveness

BACKGROUND: Children with comorbidities are at greater risk of severe influenza outcomes compared with healthy children. In Australia, influenza vaccination was funded for those with comorbidities from 2010 and all children aged <5 years from 2018. Influenza vaccine coverage remains inadequate in children with and without comorbidities. METHODS: Children ≤16 years admitted with acute respiratory illness and tested for influenza at sentinel hospitals were evaluated (2010-2019). Multivariable regression was used to identify predictors of severe outcomes. Vaccine effectiveness was estimated using the modified incidence density test-negative design. RESULTS: Overall, 6057 influenza-confirmed hospitalized cases and 3974 test-negative controls were included. Influenza A was the predominant type (68.7%). Comorbidities were present in 40.8% of cases. Children with comorbidities were at increased odds of ICU admission, respiratory support, longer hospitalizations, and mortality. Specific comorbidities including neurological and cardiac conditions increasingly predisposed children to severe outcomes. Influenza vaccine coverage in influenza negative children with and without comorbidities was low (33.5% and 17.9%, respectively). Coverage improved following introduction of universal influenza vaccine programs for children <5 years. Similar vaccine effectiveness was demonstrated in children with (55% [95% confidence interval (CI): 45; 63%]) and without comorbidities (57% [(95%CI: 44; 67%]). CONCLUSIONS: Comorbidities were present in 40.8% of influenza-confirmed admissions and were associated with more severe outcomes. Children with comorbidities were more likely experience severe influenza with ICU admission, mechanical ventilation, and in-hospital morality. Despite demonstrated vaccine effectiveness in those with and without comorbidities, vaccine coverage was suboptimal. Interventions to increase vaccination are expected to reduce severe influenza outcomes