Objective To estimate the real world effectiveness of modified vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine against mpox infection. Design Emulation of a target trial. Setting Linked databases in Ontario, Canada. Participants 9803 men aged ≥18 years with a history of being tested for syphilis and a laboratory confirmed bacterial sexually transmitted infection (STI) in the previous year, or who filled a prescription for HIV pre-exposure prophylaxis in the previous year. On each day between 12 June 2022 and 27 October 2022, those who had been vaccinated 15 days previously were matched 1:1 with unvaccinated men by age, geographical region, past HIV diagnosis, number of bacterial STI diagnoses in the previous three years, and receipt of any non-MVA-BN vaccine in the previous year. Main outcome measure The main outcome measure was vaccine effectiveness ((1–hazard ratio)×100) of one dose of subcutaneously administered MVA-BN against laboratory confirmed mpox infection. A Cox proportional hazards model was used to estimate hazard ratios to compare the rate of laboratory confirmed mpox between the two groups. Results 3204 men who received the vaccine were matched to 3204 unvaccinated controls. A total of 71 mpox infections were diagnosed, with 0.09 per 1000 person days (95% confidence interval (CI) 0.05 to 0.13) in the vaccinated group and 0.20 per 1000 person days (0.15 to 0.27) in the unvaccinated group over the study period of 153 days. Estimated vaccine effectiveness of one dose of MVA-BN against mpox infection was 58% (95% CI 31% to 75%). Conclusion The findings of this study, conducted in the context of a targeted vaccination programme and evolving outbreak of mpox, suggest that one dose of MVA-BN is moderately effective in preventing mpox infection. The dataset from this study is held securely in coded form at ICES. While legal data sharing agreements between ICES and data providers (eg, healthcare organisations and government) prohibit ICES from making the dataset publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at (email das@ices.on.ca). The full dataset creation plan and underlying analytical code are available from the authors upon request, understanding that the computer programs may rely upon coding templates or macros that are unique to ICES and are therefore either inaccessible or may require modification. Correspondence and requests for materials should be addressed to JCK or SM.

中文翻译：

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改良牛痘安卡拉-巴伐利亚北欧疫苗对 mpox 感染的有效性：靶向试验的模拟


目的 评估改良牛痘安卡拉-巴伐利亚北欧 （MVA-BN） 疫苗对 mpox 感染的真实世界有效性。目标试验的设计仿真。在加拿大安大略省设置链接数据库。参与者 9803 名年龄在 ≥18 岁之间，有梅毒检测史且前一年经实验室证实的细菌性传播感染 （STI），或前一年填写了 HIV 暴露前预防处方的男性。在 2022 年 6 月 12 日至 2022 年 10 月 27 日期间的每一天，根据年龄、地理区域、过去的 HIV 诊断、过去三年的细菌性传播感染诊断数量以及上一年接受过任何非 MVA-BN 疫苗，将 15 天前接种疫苗的人与未接种疫苗的男性进行 1：1 匹配。主要结局指标 主要结局指标是一剂皮下注射 MVA-BN 对实验室确诊的 mpox 感染的疫苗有效性 （（1-风险比）×100）。采用 Cox 比例风险模型估计风险比，比较两组实验室确诊 mpox 的发生率。结果 将 3204 名接种疫苗的男性与 3204 名未接种疫苗的对照者相匹配。在 153 天的研究期间，共诊断出 71 例 mpox 感染，接种疫苗组每 1000 人天 0.09 例 （95% 置信区间 （CI） 0.05 至 0.13），未接种疫苗组每 1000 人天 0.20 例 （0.15 至 0.27）。据估计，一剂 MVA-BN 对 mpox 感染的疫苗有效性为 58%（95% CI [31%， 75%]）。结论 这项研究的结果是在有针对性的疫苗接种计划和 mpox 不断发展的爆发背景下进行的，结果表明一剂 MVA-BN 对预防 mpox 感染具有中等效果。 本研究的数据集以编码形式安全地保存在 ICES。虽然 ICES 与数据提供者（例如，医疗保健组织和政府）之间的法律数据共享协议禁止 ICES 公开提供数据集，但可以向符合预先指定保密访问标准的人授予访问权限，网址为 （电子邮件 das@ices.on.ca）。作者可应要求提供完整的数据集创建计划和基础分析代码，了解计算机程序可能依赖于 ICES 独有的编码模板或宏，因此无法访问或可能需要修改。信件和材料请求应发送至 JCK 或 SM。