Immunology of Aging: the Birth of Inflammaging.

The inflammaging concept was introduced in 2000 by Prof. Franceschi. This was an evolutionary or rather a revolutionary conceptualization of the immune changes in response to a lifelong stress. This conceptualization permitted to consider the lifelong proinflammatory process as an adaptation which could eventually lead to either beneficial or detrimental consequences. This dichotomy is influenced by both the genetics and the environment. Depending on which way prevails in an individual, the outcome may be healthy longevity or pathological aging burdened with aging-related diseases. The concept of inflammaging has also revealed the complex, systemic nature of aging. Thus, this conceptualization opens the way to consider age-related processes in their complexity, meaning that not only the process but also all counter-processes should be considered. It has also opened the way to add new concepts to the original one, leading to better understanding of the nature of inflammaging and of aging itself. Finally, it showed the way towards potential multimodal interventions involving a holistic approach to optimize the aging process towards a healthy longevity.

Immunosenescence and COVID-19.

Ageing is associated with modified function of both innate and adaptive immunity. It is believed that changes occurring in ageing immune system are responsible for increased severity and deadliness of COVID-19 in the elderly. Although supported by statistics and epidemiology, these finding do not compute at the mechanistic level as depending solely on chronological and biological ageing. The phenomena describing changes in the aging immune system are immunosenescence and inflammageing, which develop in time depending on challenges to the individual immune system (immunobiography). Thus, "richer" immunobiography (in addition to other factors, including genetic, epigenetics or metabolic) may adversely affect the reactivity to the SARS-CoV-2 not only at later decades of life, but also earlier, in young and middle-aged individuals. On the other hand, infection with SARS-CoV-2 is affecting the function of both innate and adaptive branches of the immune system, adding to the individual immunobiography. Summarizing, immunosenescence and inflammaging may aggravate, but also may be aggravated by SARS-CoV-2 infection.

Immunosenescence and Altered Vaccine Efficiency in Older Subjects: A Myth Difficult to Change.

Organismal ageing is associated with many physiological changes, including differences in the immune system of most animals. These differences are often considered to be a key cause of age-associated diseases as well as decreased vaccine responses in humans. The most often cited vaccine failure is seasonal influenza, but, while it is usually the case that the efficiency of this vaccine is lower in older than younger adults, this is not always true, and the reasons for the differential responses are manifold. Undoubtedly, changes in the innate and adaptive immune response with ageing are associated with failure to respond to the influenza vaccine, but the cause is unclear. Moreover, recent advances in vaccine formulations and adjuvants, as well as in our understanding of immune changes with ageing, have contributed to the development of vaccines, such as those against herpes zoster and SARS-CoV-2, that can protect against serious disease in older adults just as well as in younger people. In the present article, we discuss the reasons why it is a myth that vaccines inevitably protect less well in older individuals, and that vaccines represent one of the most powerful means to protect the health and ensure the quality of life of older adults.