Balancing strategies in vaccination and mask-wearing for Chinese medical staff in post-COVID-19 era: a modelling study and cost-effectiveness analysis.

Background: After the comprehensive easing of COVID-19 restrictions in China in December 2022, the emergence of additional virus variants and repeat infections has garnered increased attention, particularly among key populations such as medical staff. Our study aims to evaluate various combinations of vaccination and mask-wearing strategies to identify the optimal strategy for the post-COVID-19 era.

Methods: A Markov model simulated a cohort of 100 000 Chinese medical staff five years after the complete lifting of epidemic restrictions. The health care system's perspective was adopted, and parameters were sourced from Chinese government-released data and relevant literature. Strategies with varying vaccination coverage (0/25/50/75%) and mask-wearing coverage (0/30/60/90%) were considered. All costs were expressed as USD with a 3% annual discounting rate, and effectiveness was measured via quality-adjusted life year. Sensitivity analyses were performed to evaluate cost-effectiveness uncertainty.

Results: At a willingness-to-pay threshold of one-time gross domestic product per capita in China (12 440 USD), the strategy of 90% mask-wearing and 75% vaccination coverage among medical staff was the most cost-effective (501 USD/quality-adjusted life year). This intervention reduced infection and mortality rates by 24.5% and 24.6%, while minimising health care costs with a cost per reversed infection of 1040 USD. Above 30% mask coverage, higher vaccine coverage further increased cost-effectiveness further. On the 16th day after lifting COVID-19 restrictions in the Markov model, there were 19 586 fewer symptomatic cases of first-time COVID-19 infection compared to the status quo (peak infections on that day = 22 293), with a reinfection circle around 197 days. Sensitivity analysis indicated that monthly mask costs is the most sensitive factor influencing the incremental cost-effectiveness ratio; beyond 6.2 USD/mo, the optimal strategy lost cost-effectiveness.

Conclusions: In managing multiple waves of the epidemic, prioritising mask usage over vaccination is recommended for medical staff to achieve optimal cost-effectiveness. Exploring ways to extend vaccine efficacy duration would further enhance protection.