HLA-B*15:01-positive severe COVID-19 patients lack CD8 T cell pools with highly expanded public clonotypes.

Understanding host factors driving asymptomatic versus severe disease outcomes is of key importance if we are to control emerging and re-emerging viral infections. HLA-B*15:01 has been associated with asymptomatic SARS-CoV-2 infection in nonhospitalized individuals of European ancestry, with protective immunity attributed to preexisting cross-reactive CD8 T-cells directed against HLA-B*15:01-restricted Spike-derived S peptide (B15/SCD8 T-cells). However, fundamental questions remained on the abundance and clonotypic nature of CD8 T-cell responses in HLA-B*15:01-positive patients who succumbed to life-threatening COVID-19.

Longitudinal Meta-cohort study protocol using systems biology to identify vaccine safety biomarkers.

The International Network of Special Immunization Services (INSIS) was established to investigate the causes and risk factors of rare adverse events following immunizations (AEFIs) and develop immunization strategies for mitigating or preventing risk for individuals with prior AEFIs or at risk of AEFIs. INSIS integrates clinical data with multi-omic technologies (e.g.

Australasian Bronchiolitis Guideline: 2025 Update.

Aim: To provide updated evidence-based clinical guidance in the management of infants with bronchiolitis presenting to emergency departments (EDs), general paediatric, or intensive care units (ICUs) in Australia and Aotearoa New Zealand (AoNZ) following the first publication in 2016.

Method: The Paediatric Research in Emergency Departments International Collaborative (PREDICT) network guideline working group appraised, summarised, and updated evidence from 1 January 2000 to 24 January 2024 addressing 41 questions (30 from the 2016 guideline and 11 new questions for 2025). Recommendations were developed using GRADE methodology and revised after a period of external consultation.

Management and outcomes of children hospitalised with COVID-19 including incidental and nosocomial infections in Australia 2020-2023: A national surveillance study.

Background: Management and outcomes of children hospitalised with acute SARS-CoV-2 infection may differ throughout the pandemic or with admission type (clinical COVID-19, incidental COVID-19 or nosocomial infection).

Objectives: Describe the severity, management and outcomes of hospitalised children with acute SARS-CoV-2 infection in Australia across the first 4 years of the pandemic and compare between admission types, SARS-CoV-2 variants, age groups and immune status.

Study Design: A multi-centre prospective cohort study of 6009 children aged 0-16 years between January 2020 and June 2023.

Respiratory syncytial virus preventives for children in Australia: current landscape and future directions.

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infections, and a leading cause of hospitalisation in children under 6 months of age. Previously, palivizumab, a costly, short-acting monoclonal antibody, was the primary preventive option. The recent introductions of nirsevimab (Beyfortus), a long-acting monoclonal antibody, and Abrysvo, a maternal RSV vaccine, have brought about significant advances in RSV prevention for children.

The Spectrum and Burden of COVID-19-Associated Neurologic Disease in Australian Children 2020-2023.

Background: We aimed to describe the clinical spectrum and burden of COVID-19-associated neurologic disease in Australian children.

Methods: We extracted Australian national sentinel site surveillance data on COVID-19-associated neurologic disease in children hospitalized in the Paediatric Active Enhanced Disease Surveillance network, 2020-2023. Neurologic complications included encephalitis, encephalopathy, Guillain-Barre syndrome, seizures and cerebrovascular accident among others.

Evaluation of SARS-CoV-2 Antibody Response Between Paired Fingerprick (HemaPEN) and Venepuncture Collected Samples in Children and Adults.

Serological surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is important to monitor population COVID-19 immunity. Dried blood spots (DBS) are a valuable method for serosurveys, particularly in remote settings and in children. We compared the measurement of SARS-CoV-2 spike-specific IgG in paired blood samples collected using standard venepuncture (serum) and the hemaPEN microsampling DBS device from children and adults.

Study of Children Aged Under 2 Years Admitted With RSV at Four Australian Hospitals [2021-2022].

Aims: Primary aim was to review severe acute respiratory infections (SARI) hospitalisations caused by respiratory syncytial virus (RSV) in children aged < 2 years in paediatric hospitals in Australia. Secondary aims included RSV subtyping, assessing RSV seasonality and contributing to the World Health Organisation's RSV surveillance programme.

Methods: We prospectively reviewed the medical records of children (< 2 years of age) with a confirmed SARI who were admitted to one of four major Australian paediatric hospitals and had a respiratory sample analysed by Polymerase Chain Reaction (PCR).

Systematic Review of Avian Influenza Virus Infection and Outcomes during Pregnancy.

Human cases of avian influenza A(H5N2) and A(H5N1) viruses associated with outbreaks in birds and mammals are increasing globally, raising concerns about the possibility of a future avian influenza pandemic. We conducted a systematic review examining 30 reported cases of avian influenza in pregnant women. We found high mortality rates for mothers (90.

Clinical phenotype of COVID-19 vaccine-associated myocarditis in Victoria, 2021-22: a cross-sectional study.

Objectives: To describe myocarditis as an adverse event after coronavirus disease 2019 (COVID-19) vaccination, including a detailed description of clinical phenotypes and diagnostic test results and differences by age, sex, and degree of troponin level elevation.

Study Design: Retrospective cross-sectional study.

Setting, Participants: Cases of suspected myocarditis following the administration of a COVID-19 vaccine in Victoria during 22 February 2021 - 30 September 2022 reported to Surveillance of Adverse Events Following Vaccination In the Community (SAEFVIC), with symptom onset within 14 days of vaccination, and deemed to be confirmed myocarditis according to the Brighton Collaboration Criteria.

Humoral and cellular immune responses in vaccinated and unvaccinated children following SARS-CoV-2 Omicron infection.

Objectives: The immune response in children elicited by SARS-CoV-2 Omicron infection alone or in combination with COVID-19 vaccination (hybrid immunity) is poorly understood. We examined the humoral and cellular immune response following SARS-CoV-2 Omicron infection in unvaccinated children and children who were previously vaccinated with COVID-19 mRNA vaccine.

Methods: Participants were recruited as part of a household cohort study conducted during the Omicron predominant wave (Jan to July 2022) in Victoria, Australia.

Detailed review of mortality reported following COVID-19 vaccination in Victoria, Australia: 2021-2023.

Introduction: The scale of the COVID-19 vaccine program, and appropriate focus on older individuals, emphasised monitoring of mortality as an important part of COVID-19 vaccine safety surveillance, noting many deaths temporally associated with vaccination may not be causally related. This cross-sectional study describes Victoria's vaccine safety service (SAEFVIC) process of reviewing mortality reports following COVID-19 vaccination, summarises report characteristics and identifies trends in mortality reporting.

Methods: Mortality cases reported to SAEFVIC following COVID-19 vaccination from 22 February 2021 to 22 February 2023 were included.

Assessing the Impact of Pneumococcal Conjugate Vaccine Immunization Schedule Change From 3+0 to 2+1 in Australian Children: A Retrospective Observational Study.

Background: In mid-2018, the Australian childhood 13-valent pneumococcal conjugate vaccine schedule changed from 3+0 to 2+1, moving the third dose to 12 months of age, to address increasing breakthrough cases of invasive pneumococcal disease (IPD), predominantly in children aged >12 months. This study assessed the impact of this change using national IPD surveillance data.

Methods: Pre- and postschedule change 3-dose 13-valent pneumococcal conjugate vaccine breakthrough cases were compared by age group, serotype, and clinical syndrome.

Accelerated Bacille Calmette-Guérin reactions: More than meets the eye.

An accelerated local injection site reaction following Bacille Calmette-Guérin (BCG) vaccination has been associated with underlying active tuberculosis (TB) in high TB-prevalence settings. The clinical significance of this accelerated BCG reaction in individuals without TB symptoms, particularly in low TB-prevalence countries, is unclear. Using safety surveillance data and baseline interferon-gamma release assays (IGRA) within an international randomised trial of BCG vaccination in healthcare workers (the BRACE trial), we aimed to determine the incidence, and investigate for clinical implications, of an accelerated BCG reaction in asymptomatic adults in low and high TB-prevalence settings.

Letter to the Editor: A comparison of post-COVID vaccine myocarditis classification using the Brighton Collaboration criteria versus (United States) Centers for Disease Control criteria: an update.

(No abstract provided).

Audiovestibular adverse events following COVID-19 vaccinations.

Introduction: Evidence regarding audiovestibular adverse events post COVID-19 vaccination to date has been inconclusive regarding a potential association. This study aimed to determine if there was an increase in audiovestibular events following COVID-19 vaccination in South-eastern Australia during January 2021-March 2023.

Methods: A multi-data source approach was applied.

Increase in invasive group A streptococcal disease among Australian children coinciding with northern hemisphere surges.

Background: Increases in invasive group A streptococcal disease (iGAS) have recently been reported in multiple countries in the northern hemisphere, occurring during, and outside of, typical spring peaks. We report the epidemiology of iGAS among children in Australia from 1 July 2018 to 31 December 2022.

Methods: The Paediatric Active Enhanced Disease Surveillance (PAEDS) Network prospectively collected iGAS patient notifications for children and young people aged less than 18 years admitted to five major Australian paediatric hospitals in Victoria, Queensland, Western Australia and the Northern Territory.

Long term follow up and outcomes of Covid-19 vaccine associated myocarditis in Victoria, Australia: A clinical surveillance study.

Background: Myocarditis and myopericarditis are well described adverse events of special interest (AESI) following COVID-19 vaccinations. Although reports are reassuring regarding initial clinical outcomes, information about longer term outcomes remains limited. We aimed to further this knowledge and report outcomes to 6 months post diagnosis from a single population cohort.

Analyzing an immunization resource website: User browsing trends.

Purpose: Access to internet-based resources may help to improve population health awareness and literacy surrounding immunization related topics. The primary aim of this study was to evaluate and analyze trends for a single immunization resource website, the Melbourne Vaccine Education Centre (MVEC).

Principal Results: Over a four-year period from 2019 to 2022, the website had over 2 million visitors from 236 countries.

Emergency department presentations for chest complaints after mRNA COVID-19 vaccinations in children and adolescents.

Objective: To investigate characteristics and management of children presenting with chest complaints to a tertiary paediatric ED post-mRNA COVID-19 vaccine.

Methods: This was a retrospective medical record review with data linkage to the Australian Immunisation Register. The study setting was the Royal Children's Hospital, Melbourne, Australia.