Cost-effectiveness of varicella vaccination of healthcare workers

Objective: Although transmission of VZV is recognized as an important cause for morbidity in health care workers (HCWs), there is no general agreement on the recommended immunization policy. This study aimed to evaluate several of such prevention policies in economic terms. Settings: Analysis of the cost per avoided future varicella cases among HCWs in Israel. Methods: A cost-effectiveness analysis was performed by comparing the cost per avoided case of varicella among a theoretical cohort of 63,353 physician and nurses aged less than 45 years in Israel. Four policies were examined: (a) do nothing (status quo); (b) vaccination of susceptible workers using VZV serotesting; with (c) or without anamnestic history of chickenpox; and (d) presumptive mass vaccination of all eligible workers. A Markov-based model was developed using data from our recent seroepidemiological study in target population and from the literature. Results: Screening and vaccination of susceptible workers using anamnestic selection is expected to reduce future cases, within 20 years since vaccination, from 58.3 to 33.0 with an incremental cost of US$ 23,713 per avoided cases. Using only serological tests to detect susceptible workers would prevent additional 5.7 cases with an incremental cost of US$ 206,692 per avoided case. Vaccinating all HCWs without serotesting, raises the costs markedly, with almost identical effectiveness, resulting in an incremental cost of US$ 10.4 million per avoided case. Sensitivity analyses do not alter the ranking of the options. Conclusion: From the employer's perspective, routine varicella vaccination program for HCWs with or without selection of susceptible workers is extremely expensive compared to other high-cost practiced approaches. Substantial reduction in cost of vaccination may alter this conclusion.