Paul V. Effler

We explored age-specific infant respiratory syncytial virus (RSV) laboratory-confirmed hospitalization rates by birth month in Western Australia. Population-based analyses were supplemented with susceptible-exposed-infected-recovered-(susceptible) mathematical model simulations. RSV-hospitalizations peaked for infants aged 1–3 months born in-season and 6–10 months born out-of-season, that is spring and summer-born infants. Offering an additional nirsevimab dose to spring and summer-born infants could avert significant hospitalizations and healthcare costs.

Background In Australia, surveillance of adverse events following immunisation is primarily conducted by states and territories, with each jurisdiction only able to view and analyse reports originating from their own population. Distributed data models (aka federated data models) are a form of decentralised collaboration, with each site maintaining ownership of its data from end-to-end including data collection, storage and analysis. The primary benefit of this model is that it maintains independence and autonomy while enabling interdependence, collaboration and scalability. Objective We aimed to investigate statistical methods for a multi-jurisdictional collaboration when conducting a rigorous assessment of rare adverse events following immunisation at a national level. Methods Victoria and Western Australia have independently established routine data linkage for vaccine safety surveillance. A data collaboration model is proposed, whereby each jurisdiction can generate de-identified population-level data for adverse events following immunisation, using agreed case definitions and analytical methods. To demonstrate its utility, Victoria and Western Australia combined data from a self-controlled case series via a meta-analysis approach using aggregate data and a pooled approach using individual-level data to investigate the association between coronavirus disease 2019 vaccines and Guillain–Barré syndrome. Results There were 519 and 176 new Guillain–Barré syndrome International Classification of Diseases, Tenth Revision, Australian Modification coded admissions in Victoria and Western Australia, respectively, between 01/01/2020 and 31/12/2023. Combining data using a fixed-effect meta-analysis method (relative incidence: 2.64, 95% confidence interval 1.90, 3.66) and a pooled method (relative incidence: 2.45, 95% confidence interval 1.76, 3.41) confirmed the known increased incidence in the 42 days following a coronavirus disease 2019 Vaxzevria^® vaccination. Both methods resulted in a decreased standard error when compared with either state alone. Conclusions This project represents an ongoing successful collaboration between two Australian jurisdictions using data linkage to investigate rare adverse events following immunisation and inform accurate benefit-risk analyses. The decision to use meta-analysis and pooled analysis methods should be considered on a case-by-case basis and may depend on data-sharing agreements, the ease of pooling potentially discordant data variables and underlying population characteristics.

Background: Nirsevimab is a long-acting monoclonal antibody used to prevent respiratory syncytial virus (RSV) infection in infants and high-risk children. During the 2024 RSV season in Western Australia, 21 922 doses were administered to infants entering their first season and 1221 doses to at-risk children. In this context, the selection and spread of escape variants are a potential concern. This study aimed to investigate nirsevimab binding site mutations using clinical and wastewater data. Methods: We performed whole genome sequencing on 382 clinical RSV samples and 12 wastewater samples collected between September 2023 and October 2024. RSV subtypes, genetic diversity, and mutations within the nirsevimab binding region of the F protein were analyzed. Phylogenetic analysis was conducted to assess lineage dynamics and the potential emergence of escape variants. Results: RSV-A was the dominant subtype (61.8%), with RSV-B accounting for 38.2% of cases. No lineage shifts were observed following nirsevimab introduction, and none of the known mutations associated with high-level nirsevimab resistance were detected in either clinical or wastewater samples. The prevalent RSV-B mutation combination (F:I206M:Q209R:S211N) was observed consistently but is not associated with reduced nirsevimab efficacy. Wastewater sampling, covering approximately 2 million people from the Perth metropolitan region, confirmed findings from clinical sequences, reinforcing the absence of resistance mutations. Conclusions: No evidence of nirsevimab escape mutations was found in clinical or wastewater samples during the 2024 RSV season. Continued genomic surveillance, including wastewater monitoring, is essential to detect emerging resistance and ensure the long-term efficacy of prophylactic interventions.

An adequately trained multidisciplinary workforce is essential to the success of any outbreak response and therefore fundamental in long-term preparedness efforts. In recognition of the critically important role that training plays in a public health emergency response, international organisations, public health institutes, and governments around the world continue to invest in designing and delivering outbreak response trainings. However, these trainings can vary in quality and utility. In this chapter, we explore the different contexts of outbreak response training and present the best practice approaches for designing and delivering outbreak and public health emergency response trainings to the highest standards.

Introduction: Nuvaxovid became available in Australia from February 2022, a year after the first COVID-19 vaccines. This protein-based vaccine was an alternative for people who had had an adverse event to and/or were hesitant to receive an mRNA or adenovirus-based COVID-19 vaccine. Although safety from clinical trials was reassuring, small trial populations, low administration rates and limited post-licensure intelligence meant potential rare adverse events were underinformed. Aim: We aimed to describe Nuvaxovid’s safety profile in a real-world setting. Methods: We conducted a retrospective observational analysis of adverse events following immunisation (AEFI) spontaneously reported to SAFEVAC, the integrated vaccine safety surveillance system in Victoria and Western Australia. Reports from 14 February 2022 to 30 June 2023 were analysed by vaccinee demographics, reported reactions and COVID-19 vaccine dose, and compared as reporting rates (RR) per 100,000 doses administered. Results: We received 356 AEFI reports, following 102,946 Nuvaxovid doses administered. Rates were higher after dose 1 than dose 2 (rate ratio: 1.5, p = 0.0008), primary series than booster (rate ratio: 2.4, p < 0.0001), and in females vs males (rate ratio: 1.4, p = 0.004). Clinically confirmed serious AEFI included 94 cases of chest pain (RR = 91.3), two myocarditis (RR = 1.9) and 20 pericarditis (RR = 19.4). Guillain–Barré syndrome or thrombosis with thrombocytopaenia syndromes were not reported, nor deaths attributable to vaccination. Conclusion: SAFEVAC’s collaborative data model enabled pooling of clinically reviewed data across jurisdictions, increasing the safety profile evidence for Nuvaxovid and improving the odds for identification and description of rare events. This analysis affirmed the safety profile of Nuvaxovid.

Introduction Nuvaxovid became available in Australia from February 2022, a year later than the first COVID-19 vaccines were released. It was a much-anticipated alternative vaccine for people that had either suffered an adverse event to–and/or were hesitant to receive–one of the mRNA or adenovirus-based COVID-19 vaccines. Although safety from clinical trials was reassuring, small trial population size, relatively low administration rates worldwide and limited post-licensure intelligence meant potential rare adverse events were underinformed. Methods We conducted a retrospective observational analysis of adverse events following immunisation (AEFI) spontaneously reported to SAFEVAC, the integrated vaccine safety surveillance system used by Victoria and Western Australia, Australia. Reports received from 14 Feb 2022 to 30 June 2023 were analysed by vaccinee demographics, reported reactions and COVID-19 vaccine dose received and compared as reporting rates (RR) per 100,000 doses administered. Results 356 AEFI reports were received, following 102,946 Nuvaxovid doses administered. Rates were higher post dose 1 than dose 2 (rate ratio 1.5, p=0.0008); primary series than booster (rate ratio 2.4, pConclusion The shared SAFEVAC platform enables pooling of clinically reviewed data across jurisdictions, increasing the safety profile evidence-base of novel vaccines like Nuvaxovid and improving the odds for identification and description of rare events across all vaccines. What did you want to address in this study and why?Nuvaxovid is a protein-based vaccine for protection against COVID-19. Nuvaxovid received provisional licensure following clinical trials in which 30,058 participants received at least one dose of Nuvaxovid. Introduced following adenoviral vector and mRNA COVID-19 vaccines, some people had been waiting for this vaccine as an alternative to other brands that had risk of blood clots or heart inflammation. We wanted to inform on safety of Nuvaxovid following over 100,000 doses administered in real-world population-wide setting in two Australian states. What have we learnt from this study?Adverse events reported were mostly mild, transient symptoms and no deaths were attributed to Nuvaxovid immunisation. Reporting rate for heart inflammation was similar to the mRNA COVID-19 vaccines, but more likely to be milder pericarditis than myocarditis. For over 25,000 people Nuvaxovid was their first dose of a COVID-19 vaccine received, despite being more than a year since COVID-19 vaccines became available. What are the implications of your findings for public health?This first real-world population-wide evidence of Nuvaxovid vaccine safety provides reassurance on the risk-benefit of vaccination for protection from severe COVID-19 disease. We must continue to look hard, using real-world data, to not only ensure vaccines are safe, but also support confidence in immunisation.

SARS-CoV-2 Vaccine Effectiveness, Australia

Background: Multiple instances of flight-associated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during long-haul flights have been reported during the COVID-19 pandemic. However, comprehensive investigations of passenger risk behaviours, before, during and after the flight, are scarce. Methods: To investigate suspected SARS-CoV-2 transmission during a flight from United Arab Emirates to Australia in July 2020, systematic, repeated polymerase chain reaction (PCR) testing of passengers in hotel quarantine was linked to whole genome sequencing. Epidemiological analyses of in-depth interviews covering behaviours during the flight and activities pre- and post-boarding were used to identify risk factors for infection. Results: Seventeen of the 95 passengers from four different travel origins had PCR-confirmed infection yielding indistinguishable genomic sequences. Two of the 17 passengers were symptomatic within 2 days of the flight, and classified as co-primary cases. Seven secondary cases were seated within two rows of the co-primary cases, but five economy passengers seated further away and three business class passengers were also infected (attack rate = 16% [15/93]). In multivariable analysis, being seated within two rows of a primary case [odds ratio (OR) 7.16; 95% confidence interval (CI) 1.66–30.85] and spending more than an hour in the arrival airport (OR 4.96; 95% CI 1.04–23.60) were independent predictors of secondary infection, suggesting travel-associated SARS-CoV-2 transmission likely occurred both during and after the flight. Self-reported increased hand hygiene, frequent aisle walking and using the bathroom on the plane did not independently affect the risk of SARS-CoV-2 acquisition. Conclusions: This investigation identified substantial in-flight transmission among passengers seated both within and beyond two rows of the primary cases. Infection of passengers in separate cabin classes also suggests transmission occurred outside the cabin environment, likely at the arrival airport. Recognizing that transmission may occur pre- and post-boarding may inform contact tracing advice and improve efforts to prevent future travel-associated outbreaks.