The Impact of Aging Oral Health on Long COVID-19.

At least 10% of individuals infected with SARS-CoV-2 develop a variety of multisystem symptoms lasting more than 12 wk known as postacute sequelae of COVID-19 (PASC) or "long COVID." While the precise pathogenesis of PASC remains unclear, immune dysregulation is widely recognized as a key factor. Moreover, PASC disproportionately affects older individuals who are prone to age-related immune system decline, which further exacerbates the risk and severity of PASC. The oral cavity, a primary site for initial SARS-CoV-2 infection, may contribute to the development and persistence of PASC. Emerging evidence suggests that changes in age-related oral health, such as periodontitis, salivary gland (SG) dysfunction, and gustatory and olfactory impairments, may create an environment conducive to forming an oral reservoir of intact virus or viral antigens, which may contribute to the chronicity of PASC. Alternatively, the pathogenesis of PASC may increase the risk of a wide range of oral health issues, such as dental diseases, dry mouth, and sensory dysfunction (e.g., taste and smell) that are frequently reported by patients with PASC. This review highlights how aging facilitates oral SARS-CoV-2 infection, co-infection with other viruses may drive PASC in aging patients, aging and PASC dysregulate the oral microbiome, SARS-CoV-2 infection promotes molecular mechanisms involved in oral tissue aging, aging oral health affects susceptibility to developing PASC, and inflammation associated with PASC exacerbates dysregulation of metabolic/enzymatic pathways of aging oral mucosa and diseases of the periodontal apparatus, SGs, and taste. It underscores the urgent need to comprehensively address the interplay between aging oral health and PASC, which will help mitigate long-term complications and improve overall health outcomes for affected individuals.