Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden; Centro Medicina dell'Invecchiamento, Fondazione Policlinico "A- Gemelli" IRCCS and Catholic University of Rome, Italy.
Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
Ageing Res Rev. 2021 Aug;69:101351. doi: 10.1016/j.arr.2021.101351. Epub 2021 May 7.
Untangling the interdependency of infections, immunity and frailty may help to clarify their roles in the maintenance of health in aging individuals, and the recent COVID-19 pandemic has further highlighted such priority. In this scoping review we aimed to systematically collect the evidence on 1) the impact of common infections such as influenza, pneumonia and varicella zoster on frailty development, and 2) the role played by frailty in the response to immunization of older adults. Findings are discussed under a unifying framework to identify knowledge gaps and outline their clinical and public health implications to foster a healthier aging. Twenty-nine studies (113,863 participants) selected to answer the first question provided a moderately strong evidence of an association between infections and physical as well as cognitive decline - two essential dimensions of frailty. Thirteen studies (34,520 participants) investigating the second aim, showed that frailty was associated with an impaired immune response in older ages, likely due to immunosenescence. However, the paucity of studies, the absence of tools to predict vaccine efficacy, and the lack of studies investigating the efficacy of newer vaccines in presence of frailty, strongly limit the formulation of more personalized immunization strategies for older adults. The current evidence suggests that infections and frailty repeatedly cross each other pathophysiological paths and accelerate the aging process in a vicious circle. Such evidence opens to several considerations. First, the prevention of both conditions pass through a life course approach, which includes several individual and societal aspects. Second, the maintenance of a well-functioning immune system may be accomplished by preventing frailty, and vice versa. Third, increasing the adherence to immunization may delay the onset of frailty and maintain the immune system homeostasis, beyond preventing infections.
理清感染、免疫和虚弱之间的相互关系，可能有助于阐明它们在维持衰老个体健康方面的作用，而最近的 COVID-19 大流行进一步突出了这一优先事项。在本次范围综述中，我们旨在系统地收集有关以下两个方面的证据：1）常见感染（如流感、肺炎和带状疱疹）对虚弱发展的影响，以及 2）虚弱在老年人免疫接种反应中所扮演的角色。研究结果在一个统一的框架下进行了讨论，以确定知识空白，并概述其对临床和公共卫生的影响，以促进更健康的老龄化。为回答第一个问题，我们选择了 29 项研究（113,863 名参与者），这些研究提供了相当有力的证据表明感染与身体和认知能力下降之间存在关联，而这两者是虚弱的两个重要维度。有 13 项研究（34,520 名参与者）调查了第二个目的，表明虚弱与老年人免疫反应受损有关，这可能是由于免疫衰老所致。然而，由于研究数量较少、缺乏预测疫苗效果的工具以及缺乏研究调查在存在虚弱的情况下新型疫苗的效果，因此严重限制了为老年人制定更个性化免疫策略的能力。目前的证据表明，感染和虚弱会在病理生理学上相互影响，并在恶性循环中加速衰老过程。这种证据引发了一些思考。首先，这两种疾病的预防都需要通过一种贯穿一生的方法，其中包括多个个体和社会方面。其次，预防虚弱可能有助于维持良好的免疫系统功能，反之亦然。第三，提高免疫接种的依从性可能会延迟虚弱的发生，并维持免疫系统的稳态，除了预防感染之外。
