Cost-Effectiveness of the Recombinant Zoster Vaccine Among People Living With HIV in Japan

Objectives

People living with HIV (PLWHIV) are susceptible to opportunistic infections including herpes zoster (HZ) and postherpetic neuralgia (PHN). The recombinant zoster vaccine (RZV) (Shingrix) is available in some countries. However, the cost-effectiveness for PLWHIV remains unknown. This study aimed to analyze the cost-effectiveness of RZV for PLWHIV ≥50 years old.

Methods

A Markov model was developed to compare the cost-effectiveness of the 2-dose RZV immunization program with no RZV immunization for PLWHIV aged ≥50 years. We built the model with a yearly cycle over a 30-year period and 6 health conditions: HZ free, HZ, PHN, HZ/PHN recovery, HZ recurrence, and death. The parameters in the model were based on previous studies and a nationwide administrative claims database in Japan. The incremental cost-effectiveness ratio (ICER), expressed as Japanese yen (JPY) per the quality-adjusted life-years (QALYs), was estimated from a societal perspective. We conducted a one-way deterministic sensitivity analysis, probabilistic sensitivity analysis with Monte Carlo simulations of 10 000 samples, and scenario analyses.

Results

The ICER of the 2-dose RZV immunization program over no RZV immunization was 78 777 774 JPY (approximately 600 000 US dollars)/QALY. The one-way deterministic sensitivity analysis showed that HZ-related utility was the most significant for ICER. All estimates in the probabilistic sensitivity analysis were located above the willingness-to-pay threshold of 5 million JPY/QALY.

Conclusions

Our study revealed that no RZV immunization was more cost-effective than the 2-dose RZV immunization program for PLWHIV aged ≥50 years. This may be useful in evidence-based policy making.