Background: As climate change impacts intensify, health systems have the double responsibility of building resilience while reducing their carbon footprint. This rapid review assessed case studies of interventions implemented towards climate resilient and low carbon health systems in six Western-Pacific countries (Australia, Fiji, South Korea, Laos PDR, Mongolia, and Viet Nam).

Methods: We conducted a rapid review of academic and grey literature. Framework analysis was applied to map case study interventions against the World Health Organization's Operational Framework for Climate Resilient (CR) and Low Carbon (LC) Health Systems.

Results: We identified 43 case studies from a yield of 605 documents. The majority of interventions were classified as LC (n=25), followed by those integrating CR and LC (n=10), and CR only (n=8). We report geographical variation with majority of case studies from Australia (n=28), followed by Viet Nam (n=5), Fiji (n=4), Laos PDR (n=3), South Korea (n=2) and Mongolia (n=1). Additional implementation characteristics included co-benefits (n=30), evaluation criteria (n=23), barriers (n=23) and enablers (n=20). No studies reported implementation costs.

Conclusion: This review reveals a lack of published evidence on practical applications of the WHO Operational Framework for CR and LC Health Systems, emphasizing the imperative for additional research, documentation, and dissemination of real-world implementation insights. We captured multiple co-benefits and emerging community engagement considerations but minimal cost-benefit analysis, hampering identification of best buys in terms of these investments. A rapid shift from fragmented mitigation efforts to comprehensive, system-wide strategies for resilience and decarbonisation is critical for transformative change across the health sector.