The Role of Immunosenescence and Inflammaging in the Susceptibility of Older Adults to SARS-CoV-2 Infection

COVID-19 is an ongoing pandemic caused by the SARS-CoV-2 coronavirus that is one of the most significant challenges to public health over the past few years. Most people are vulnerable to SARS-CoV-2, but older adults are more vulnerable. Aging is one of the major risk factors for the detrimental consequences of COVID-19, likely due to chronic inflammation and immunosenescence, both of which are the characteristics of old age. Immunosenescence refers to the weakening of the immune system with age while inflammaging describes the low-grade chronic inflammation seen in older individuals. One key aspect of human aging is immune deficiency. During aging, our body's defense system weakens, resulting in decreased responses to infection by novel pathogens and a reduced ability to become immunized. The presence of chronic inflammation and viral infection in old age may cause several adverse unpredictable outcomes increasing the propensity and severity of the disease and requires to be considered, enabling people to better prepare for the potential consequences of this ongoing pandemic. This requires consideration so that individuals can better be prepared to address the potential consequences of this ongoing pandemic. In this review, we discuss the clinical characteristics of elderly COVID-19 patients and survey the associated molecular pathways that are pivotal for the interactions of the coronavirus and host cellular responses, including immunosenescence, inflammation, telomere attrition, impaired autophagy, mitochondrial dysfunction and alterations in major aging signaling pathways, which are crucial for the discovery of new therapeutic and preventive methods in the ongoing pandemic.