History illustrates the remarkable public health impact of mass vaccination, by dramatically improving life expectancy and reducing the burden of infectious diseases and co-morbidities worldwide. It has been perceived that if an individual adhered to the MMR vaccine schedule that immunity to mumps virus (MuV) would be lifelong. Recent mumps outbreaks in individuals who had received two doses of the Measles Mumps Rubella (MMR) vaccine has challenged the efficacy of the MMR vaccine. However, clinical symptoms, complications, viral shedding and transmission associated with mumps infection has been shown to be reduced in vaccinated individuals, demonstrating a benefit of this vaccine. Therefore, the question of what constitutes a good mumps vaccine and how its impact is assessed in this modern era remains to be addressed. Epidemiology of the individuals most affected by the outbreaks (predominantly young adults) and variance in the circulating MuV genotype have been well-described alluding to a collection of influences such as vaccine hesitancy, heterogeneous vaccine uptake, primary, and/or secondary vaccine failures. This review aims to discuss in detail the interplay of factors thought to be contributing to the current mumps outbreaks seen in highly vaccinated populations. In addition, how mumps diagnoses has progressed and impacted the understanding of mumps infection since a mumps vaccine was first developed, the limitations of current laboratory tests in confirming protection in vaccinated individuals and how vaccine effectiveness is quantified are also considered. By highlighting knowledge gaps within this area, this state-of-the-art review proposes a change of perspective regarding the impact of a vaccine in a highly vaccinated population from a clinical, diagnostic and public perspective, highlighting a need for a paradigm shift on what is considered vaccine immunity.

历史证明，大规模疫苗接种可以显着提高预期寿命并减轻全世界传染病和合并症的负担，从而对公共卫生产生显着影响。人们认为，如果一个人遵守 MMR 疫苗接种计划，则对腮腺炎病毒 (MuV) 的免疫力将是终生的。最近在接受两剂麻疹腮腺炎风疹 (MMR) 疫苗的个体中爆发的腮腺炎疫情对 MMR 疫苗的功效提出了挑战。然而，在接种疫苗的个体中，与腮腺炎感染相关的临床症状、并发症、病毒脱落和传播已被证明有所减少，这证明了这种疫苗的益处。因此，什么是好的腮腺炎疫苗以及如何评估其在当今时代的影响的问题仍有待解决。受疫情影响最严重的个体（主要是年轻人）的流行病学和循环 MuV 基因型的变异已得到充分描述，暗示了一系列影响，例如疫苗犹豫、异质疫苗摄取、初次和/或二次疫苗失败。本综述旨在详细讨论被认为导致当前高疫苗接种人群中流行性腮腺炎爆发的因素之间的相互作用。此外，还考虑了自首次开发腮腺炎疫苗以来腮腺炎诊断的进展以及对腮腺炎感染的理解的影响，当前实验室测试在确认接种疫苗的个体中的保护方面的局限性以及如何量化疫苗有效性。 通过强调这一领域的知识差距，这篇最先进的综述从临床、诊断和公众的角度提出了关于疫苗对高度接种疫苗的人群的影响的观点的改变，强调需要进行范式转变什么是疫苗免疫力。