Modeling the potential public health and economic impact and cost-effectiveness of vaccination strategies using an adapted COVID-19 vaccine in Guatemala

BACKGROUND: Using adapted COVID-19 vaccines targeting current variants in circulation is necessary for addressing the dynamic evolution of the SARS-CoV-2 virus. RESEARCH DESIGN AND METHODS: Using a previously published combined Markov-decision tree model, this study estimated the outcomes of different vaccination strategies targeting various age and risk groups. The model used age-specific epidemiology, clinical, cost, and quality-of-life inputs derived from published literature and national surveillance data. Scenario analyses that included variations in COVID-19 incidence and sensitivity analyses that varied the parameters by ±20% were both conducted. RESULTS: Compared to no vaccination, the vaccination of older adults aged ≥65 years and the high-risk population was estimated to prevent 12, 933 symptomatic cases, 12, 811 outpatient cases, 122 hospitalizations, 353 lost quality-adjusted life-years (QALYs) gained, and four deaths, translating to total direct and societal cost savings of US9, 424, 605 and US10, 397, 107 respectively. Expanding vaccination to adults aged ≥60 years and high-risk individuals further increased public health and economic benefits. Results were sensitive to assumptions regarding the underlying burden of infection, particularly underreporting. CONCLUSIONS: Implementing an adapted COVID-19 vaccine strategy for high-risk and older adults in Guatemala is projected to improve health outcomes and, under base-case assumptions, be cost-saving from both payer and societal perspectives.