Pathology of TB/COVID-19 Co-Infection: The phantom menace

Tuberculosis (TB) and coronavirus disease 2019 (COVID-19) are currently the two main causes of death among infectious diseases. There is an increasing number of studies trying to elucidate the interactions between Mycobacterium tuberculosis and SARS-CoV-2. Some of the first case reports point to a worsening of respiratory symptoms in co-infected TB/COVID-19 individuals. However, data from the cohort studies has shown some conflicting results. This study proposes to conduct a systematic review on the current literature on TB/COVID-19 co-infection cohorts, evaluating clinical and epidemiological data, focusing on its implications to the immune system. From an immunological perspective, the TB/COVID-19 co-infection has the potential to converge in a "perfect storm". The disorders induced by each pathogen to the immunomodulation tend to induce an unbalanced inflammatory response, which can promote the progression and worsening of both diseases. Understanding the nature of the interactions between M. tuberculosis and SARS-CoV-2 will be crucial for the development of therapeutic strategies against co-infection. •Tuberculosis and COVID-19 are currently the two main causes of death among infectious diseases worldwide.•Both diseases shares some clinical features, which impairs its diagnosis and, therefore, its treatment.•Tuberculosis is a risk factor for COVID-19 and co-infected individuals tend to present a worse prognosis.•.Many of the damages and complications of co-infection are result from an exacerbated inflammatory response.•TB / COVID-19 co-infection appears to generate self-sustaining pro-inflammatory feedback, impairing lung function.