Tuberculosis and COVID-19 in the elderly: factors driving a higher burden of disease

Abstract

Mycobacterium tuberculosis (M.tb) and SARS-CoV-2 are both infections that can lead to severe disease in the lower lung. However, these two infections are caused by very different pathogens (Mycobacterium vs. virus), they have different mechanisms of pathogenesis and immune response, and differ in how long the infection lasts. Despite the differences, SARS-CoV-2 and M.tb share a common feature, which is also frequently observed in other respiratory infections: the burden of disease in the elderly is greater. Here, we discuss possible reasons for the higher burden in older adults, including the effect of co-morbidities, deterioration of the lung environment, auto-immunity, and a reduced antibody response. While the answer is likely to be multifactorial, understanding the main drivers across different infections may allow us to design broader interventions that increase the health-span of older people.

Latent Tuberculosis Infection and COVID-19: Analysis of a Cohort of Patients from Careggi University Hospital (Florence, Italy)

“…COVID-19-associated mortality is notably increased by aging, disabilities, and underlying medical conditions [14,[19][20][21]. However, data regarding the relationship between COVID-19 outcome and active or latent TB are few and discordant in the available literature.…”

“…According to some studies, poorer COVID-19 outcomes could be associated with active TB, probably due to the dysregulation of immunity during MT infection [11,13,14,21,23]. Global TB/COVID-19 network study group evidenced that patients diagnosed with COVID-19 after the end of TB treatment had a poorer prognosis in comparison with those with COVID-19 diagnosed before or during TB treatment [13].…”

“…In the available literature, data regarding the relationship between COVID-19 and active or latent TB are few and discordant. Some reports from TB endemic countries evidenced that COVID-19 patients coinfected with TB (COVID-TB) have a higher risk of death than those infected with a single pathogen [9,10], leading to a high mortality rate, especially in the elderly population [11][12][13][14]. Conversely, an Italian study reported a lower mortality rate in COVID-TB patients, with results likely being influenced by a younger population and fewer comorbidities [15].…”