OBJECTIVES: Due to their immunocompromised (IC) state, approximately 1-2% of the UK population are unable to mount an appropriate vaccine response. They thus remain at increased risk of severe/fatal COVID-19 disease and its fiscal and health-related quality of life impacts. The PROVENT trial showed that administration of two long-acting monoclonal antibodies (AZD7442) significantly prevented COVID-19. This study examines the health and cost benefits of such prevention in IC patients across a range of infection and hospitalization risk estimates.

METHODS: A combined decision tree and Markov model was used to evaluate the impact on health and economic outcomes of AZD7442 vs. standard care (SC) from a UK payer perspective. Time horizons of 1-year for infection risk, and lifetime for patient outcomes, were used. Model inputs were informed by a targeted literature review for epidemiological, clinical, and cost data, as well as the PROVENT trial, real-world evidence, and an estimate for the psychosocial benefit associated with prophylaxis. UK case data were used to estimate a base case symptomatic infection rate of 22.5%. A hospitalisation risk for IC patients of 17.1% was applied using published registry data from the UK Primary Immunodeficiency Network (UKPIN). Uncertainty was investigated using deterministic and probabilistic sensitivity analysis (PSA).

RESULTS: Prevention with AZD7442 was cost-effective with an incremental cost-effectiveness ratio (ICER) under £30,000 per QALY vs. SC. It was also cost-effective across the majority of PSA simulations, and plausible ranges of key model inputs explored in sensitivity analyses.

CONCLUSIONS: AZD7442 significantly reduces COVID-19 risk and cost burden in the IC population and is cost-effective at a willingness-to-pay threshold of £30,000 per QALY.