{
  "abstract": "Introduction Following widespread exposure to Omicron variants, SARS-CoV-2 has transitioned to endemic circulation. Populations now have diverse infection and vaccination histories, resulting in heterogeneous immune landscapes. Careful consideration of the value of ongoing vaccination is required through the post-Omicron phase of COVID-19 management to minimise disease burden. We demonstrate the utility of a modelling approach to address this question, supporting recommendations for targeted vaccine use across different country settings.Methods We integrated immunological, transmission, clinical and cost-effectiveness models and simulated populations with different characteristics and immune landscapes over the early post-Omicron period. We calculated the expected number of infections, hospitalisations and deaths for different vaccine scenarios. Costs (from a healthcare perspective) were estimated for exemplar country income-level groupings in the Western Pacific Region using pandemic-era vaccine prices and healthcare-seeking behaviour assumptions. We assessed the impact and cost-effectiveness of targeted vaccination strategies. Results are reported as incremental costs and disability-adjusted life years averted compared with no additional vaccination. Parameter and stochastic uncertainty were captured through scenario and sensitivity analysis.Results Across different population demographics and income levels, we consistently found that annual elder-targeted boosting strategies are most likely to be cost-effective or cost-saving (>75% probability of being cost-effective among older, high-income settings; >50% probability of being cost-effective in younger, middle-income settings), while paediatric programmes are unlikely to be cost-effective. Results remained broadly consistent while accounting for uncertainties in the epidemiological and economic models, although they were sensitive to the cost of home-based care and vaccination. Use of pandemic-era vaccine prices may underestimate current vaccine prices available in upper-middle-income and high-income settings, potentially overestimating the cost-effectiveness of boosting in these settings. Half-yearly boosting may only be cost-effective in higher income settings with older population demographics and higher cost-effectiveness thresholds.Conclusion Competing health priorities and resource constraints mean COVID-19 vaccine allocation needs to be carefully considered in context. These results, reflecting modelling conducted on the early post-Omicron period, demonstrate the value of continued booster vaccinations to protect against severe COVID-19 disease outcomes across high-income and middle-income settings and show that the biggest health gains relative to vaccine costs are achieved by targeting older age groups.",
  "authors": [
    {
      "affiliations": [
        "School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia",
        "Melbourne Centre for Data Science, School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia",
        "Centre of Excellence for Biosecurity Risk Analysis, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Thao P Le"
    },
    {
      "affiliations": [
        "Population Health & Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia"
      ],
      "name": "Eamon Conway"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Edifofon Akpan"
    },
    {
      "affiliations": [
        "School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia",
        "Melbourne Centre for Data Science, School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Isobel R Abell"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Patrick Abraham"
    },
    {
      "affiliations": [
        "School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia",
        "Melbourne Centre for Data Science, School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia",
        "Centre of Excellence for Biosecurity Risk Analysis, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Christopher M Baker"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia",
        "Department of Infectious Diseases at The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Patricia T Campbell"
    },
    {
      "affiliations": [
        "Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia"
      ],
      "name": "Deborah Cromer"
    },
    {
      "affiliations": [
        "Department of Econometrics and Business Statistics, Monash University, Melbourne, Victoria, Australia"
      ],
      "name": "Michael J Lydeamore"
    },
    {
      "affiliations": [
        "Population Health & Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia"
      ],
      "name": "Yasmine McDonough"
    },
    {
      "affiliations": [
        "Population Health & Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia",
        "Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Ivo Mueller"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia",
        "The Kids Research Institute Australia, Nedlands, Western Australia, Australia"
      ],
      "name": "Gerard Ryan"
    },
    {
      "affiliations": [
        "School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Camelia Walker"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Yingying Wang"
    },
    {
      "affiliations": [
        "Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia"
      ],
      "name": "Natalie Carvalho"
    },
    {
      "affiliations": [
        "Department of Infectious Diseases at The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia",
        "Victorian Infectious Diseases Reference Laboratory Epidemiology Unit, The Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia"
      ],
      "name": "Jodie McVernon"
    }
  ],
  "title": "Health impact and cost-effectiveness of COVID-19 booster vaccination strategies in the early post-Omicron era: a dynamic modelling study",
  "uid": "119b3c53-241e-5332-aef6-ffd7c2bd5584"
}