OBJECTIVES:

Despite the availability of COVID-19 vaccines, individuals with IC conditions remain at increased risk of severe COVID-19. Approximately 82% of immunocompromised (IC) individuals modify their lifestyle to avoid SARS-CoV-2 and 13% fully shield. Pre-exposure prophylaxis (PrEP) has been demonstrated to reduce perceived risk and improve health-related quality of life (HRQoL) through psychosocial benefits in previous economic evaluations (NICE TA246, TA769). A vignette study recently reported a substantial psychosocial HRQoL benefit in IC individuals at risk from COVID-19; this has not been previously considered in published economic evaluations in the disease area. This study assesses the impact of including a psychosocial utility benefit associated with PrEP on the cost-effectiveness of tixagevimab-cilgavimab PrEP.

METHODS:

A combined decision tree and Markov model were used to evaluate the cost-effectiveness of tixagevimab-cilgavimab PrEP vs. standard care over a lifetime horizon in the UK. A psychosocial utility benefit associated with PrEP was included based on results of the recent utility vignette study. Results demonstrated a utility gain of 0.083 (n=41) associated with PrEP in patients not shielding but making lifestyle modifications, and 0.175 (n=3) in patients who fully shield. A weighted average utility gain of 0.0976 was calculated assuming 82% of high-risk IC patients modifying behaviours, 13% fully shielding.

RESULTS:

Results without considering the psychosocial anxiety benefits show tixagevimab-cilgavimab PrEP is cost-effective at a WTP threshold of £30,000 with an associated incremental QALY benefit of 0.089. When including the psychosocial anxiety benefit, incremental QALYs increase to 0.182 substantially improving the cost-effectiveness of tixagevimab-cilgavimab PrEP.

CONCLUSIONS:

Results propose a significant uncaptured benefit when not considering the psychosocial impact of PrEP and will lead to a significant underestimation of economic value to health systems. Given this, the QALY-gain associated with the reduction in psychosocial anxiety should be a fundamental consideration for the evaluation of PrEP therapeutics.