Background More than 50 million influenza infections and over 100,000 deaths from influenza occur annually. While Indigenous populations experience an inequitable influenza burden, the magnitude of this inequity has not previously been estimated on a global scale. This study compared rates of influenza-associated hospitalisation and mortality between Indigenous and non-Indigenous populations globally. Methods A systematic review and meta-analysis was conducted including literature published prior to 13 July 2021. Eligible articles either reported a rate ratio (RR) comparing laboratory-confirmed influenza-associated hospitalisation and/or mortality between an Indigenous population and a corresponding benchmark population, or reported sufficient information for this to be calculated using publicly available data. Findings were reported by country/region and pooled by country and period (pandemic/seasonal) when multiple studies were available using a random-effects model. The I2 statistic assessed variability between studies. Results Thirty-six studies (moderate/high quality) were included; all from high or high-middle income countries. The pooled influenza-associated hospitalisation RR (HRR) for indigenous compared to benchmark populations was 5·7 (95% CI: 2·7–12·0) for Canada, 5·2 (2.9–9.3) for New Zealand, and 5.2 (4.2–6.4) for Australia. Of the Australian studies, the pooled HRR for seasonal influenza was 3.1 (2·7–3·5) and for pandemic influenza was 6·2 (5·1–7·5). Heterogeneity was slightly higher among studies of pandemic influenza than seasonal influenza. The pooled mortality RR was 4.1 (3·0–5.7) in Australia and 3·3 (2.7–4.1) in the United States. Conclusions Ethnic inequities in severe influenza persist and must be addressed by reducing disparities in the underlying determinants of health. Influenza surveillance systems worldwide should include Indigenous status to determine the extent of the disease burden among Indigenous populations. Ethnic inequities in pandemic influenza illustrate the need to prioritise Indigenous populations in pandemic response plans.

The impact and frequency of infectious disease outbreaks demonstrate the need for timely genomic surveillance to inform public health responses. In the largest known outbreak of mpox, genomic surveillance efforts have primarily focused on high-incidence nations in Europe and the Americas, with a paucity of data from South-East Asia and the Western Pacific. Here we analyzed 102 monkeypox virus (MPXV) genomes sampled from 56 individuals in Melbourne, Australia. All genomes fell within the 2022 MPXV outbreak lineage (B.1), with likely onward local transmission detected. We observed within-host diversity and instances of co-infection, and highlight further examples of structural variation and apolipoprotein B editing complex-driven micro-evolution in the current MPXV outbreak. Updating our understanding of MPXV emergence and diversification will inform public health measures and enable monitoring of the virus' evolutionary trajectory throughout the mpox outbreak.

Journal Article Absence of transmission of mpox infection on long international flights Get access Helen M O’Brien, MSc, Helen M O’Brien, MSc Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia To whom correspondence should be addressed. Email: helen.o'brien@health.vic.gov.au Search for other works by this author on: Oxford Academic PubMed Google Scholar Min-Ho Jung, MSc, Min-Ho Jung, MSc Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Stephanie C Tran, BAVSc, Stephanie C Tran, BAVSc Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Sarah I Lewis, BPubHealth&HealthProm, Sarah I Lewis, BPubHealth&HealthProm Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Janet E Strachan, MTH, Janet E Strachan, MTH Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Mihaela Ivan, MD, Mihaela Ivan, MD Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Maxwell S Braddick, MPH, Maxwell S Braddick, MPH Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar N Deborah Friedman, MD N Deborah Friedman, MD Victorian Department of Health, Communicable Diseases Section, Health Protection Branch, Melbourne, VIC 3000, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Travel Medicine, Volume 30, Issue 5, July 2023, taad075, https://doi.org/10.1093/jtm/taad075 Published: 07 June 2023 Article history Received: 02 May 2023 Revision received: 22 May 2023 Revision requested: 29 May 2023 Accepted: 29 May 2023 Published: 07 June 2023 Corrected and typeset: 23 June 2023

To the Editor: The flavivirus Murray Valley encephalitis virus (MVEV) was isolated in 1951 from the brain tissue of fatal cases of encephalitis.1 Subsequent work by Australian investigators established MVEV as the likely aetiological pathogen of the severe encephalitis “Australian X disease”.1 MVEV is enzootic in northern Western Australia and the Northern Territory, resulting in sporadic human cases.2 In southeast Australia, however, MVEV activity can be absent for decades only to reappear with significant human outbreaks. The three most recent outbreaks in Australia were in 1951 (45 cases), 1974 (58 cases) and 2011 (17 cases).13 The case fatality rate is about 18% in hospitalised patients, reflecting the severity of disease.4

IntroductionMurray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus known to cause infrequent yet substantial human outbreaks around the Murray Valley region of south-eastern Australia, resulting in significant mortality.MethodsThe public health response to MVEV in Victoria in 2022–2023 included a climate informed pre-season risk assessment, and vector surveillance with mosquito trapping and laboratory testing for MVEV. Human cases were investigated to collect enhanced surveillance data, and human clinical samples were subject to serological and molecular testing algorithms to assess for co-circulating flaviviruses. Equine surveillance was carried out via enhanced investigation of cases of encephalitic illness. Integrated mosquito management and active health promotion were implemented throughout the season and in response to surveillance signals.FindingsMosquito surveillance included a total of 3,186 individual trapping events between 1 July 2022 and 20 June 2023. MVEV was detected in mosquitoes on 48 occasions. From 2 January 2023 to 23 April 2023, 580 samples (sera and CSF) were tested for flaviviruses. Human surveillance detected 6 confirmed cases of MVEV infection and 2 cases of “flavivirus-unspecified.” From 1 September 2022 to 30 May 2023, 88 horses with clinical signs consistent with flavivirus infection were tested, finding one probable and no confirmed cases of MVE.DiscussionThe expanded, climate-informed vector surveillance system in Victoria detected MVEV in mosquitoes in advance of human cases, acting as an effective early warning system. This informed a one-health oriented public health response including enhanced human, vector and animal surveillance, integrated mosquito management, and health promotion.