In July 2022, the ongoing monkeypox (MPX) outbreak was declared a public health emergency of international concern. Modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN, also known as Imvamune, Jynneos, or Imvanex) is a 3^rd generation smallpox vaccine that is authorized and in use as a vaccine against MPX. To date, there is no data demonstrating MPX virus (MPXV)-neutralizing antibodies in vaccinated individuals, or vaccine efficacy against MPX. We show here that MPXV-neutralizing antibodies can be detected after MPXV infection and after historic smallpox vaccination. However, a 2-shot MVA-BN immunization series in non-primed individuals yields relatively low levels of MPXV-neutralizing antibodies. Dose-sparing of an MVA-based influenza vaccine leads to lower MPXV-neutralizing antibody levels, whereas a third vaccination with the same MVA-based vaccine significantly boosts the antibody response. As the role of MPXV-neutralizing antibodies as a correlate of protection against disease and transmissibility is currently unclear, we conclude that cohort studies following vaccinated individuals are necessary to assess vaccine efficacy in at-risk populations.

2022 年 7 月，持续爆发的猴痘 (MPX) 疫情被宣布为国际关注的突发公共卫生事件。改良型牛痘病毒 Ankara-Bavarian Nordic（MVA-BN，也称为 Imvamune、Jynneos 或 Imvanex）是^第三种一代天花疫苗已获授权并用作 MPX 疫苗。迄今为止，尚无数据表明接种疫苗的个体产生了 MPX 病毒 (MPXV) 中和抗体，或疫苗对 MPX 的功效。我们在此表明​​，在猴痘病毒感染后和历史性天花疫苗接种后可以检测到猴痘病毒中和抗体。然而，在非初免个体中进行的 2 针 MVA-BN 免疫系列产生的猴痘病毒中和抗体水平相对较低。基于 MVA 的流感疫苗的剂量节约导致猴痘病毒中和抗体水平降低，而第三次接种相同的基于 MVA 的疫苗可显着增强抗体反应。由于猴痘病毒中和抗体在预防疾病和传播方面的相关作用目前尚不清楚，