TB and COVID-19 coinfection: Investigating the clinical and biological interactions between Mycobacterium tuberculosis and SARS-CoV-2

Lead Research Organisation: University of Birmingham
Department Name: Institute of Immunology & Immunotherapy


The novel SARS-CoV-2 and ancient Mycobacterium tuberculosis (M.tb) represent a collision of the public health emergencies and coinfection with these infectious pathogens could have disastrous consequences for the UK and internationally.

There is significant potential for COVID-19 to superimpose on M.tb infections, resulting in coinfections that co-exacerbate. This may potentially be more important in indolent, latent tuberculosis infections (LTBI), which are typically well-controlled by active, ongoing immunity. For instance, SARS-CoV-2 causes marked lymphopenia in symptomatic COVID-19 disease. Since antigen-specific T-cell responses are crucial for the control of M.tb and in LTBI diagnostics, this may have serious sequelae. Moreover, preliminary studies suggest that TB infection and disease increase susceptibility and disease severity in COVID-19. However, this relationship is poorly characterised - naturally, there is currently more opinion in the literature than data. There are no data about the influence of SARS-CoV-2 on the progression of LTBI to active TB (ATB) and no experimental data surrounding immunopathological aspects of M.tb and SARS-CoV-2 coinfection.

To answer these unknowns we will address the following hypothesis and objectives:

Hypothesis "SARS-CoV-2 infection impairs immune control of M.tb, leading to progression of LTBI to ATB, confounding LTBI diagnostics and limiting TB control programme delivery"

1. To determine the effects of SARS-CoV-2 on immune control of M.tb in TB infection, disease and diagnostics
2. To study the incidence of COVID-19 among patients with ATB and LTBI, and its impact on disease severity and provision of TB control services

Technical Summary

UKRI priority areas include understanding the interaction between SARS-CoV-2 and other pathogens. M.tb and SARS-CoV-2 have significant potential to interact and therefore impact on clinical outcomes.

The two major knowledge gaps to be addressed by this project are:

1. The reciprocal biological impact of SARS-CoV-2 and M.tb on immunity to each other
2. How the pandemic has affected outcomes and the provision of TB services

Research to date has focussed on retrospective studies exploring relationships between TB and COVID-19 and suggest M.tb increases susceptibility to SARS-CoV-2 and disease severity. The control of LTBI requires the maintenance of effective T-cell responses. When these are perturbed (e.g. HIV infection, anti-TNF treatment), the risk of reactivation increases significantly. SARS-CoV- 2 infections may cause lymphopenia and the impact of this on M.tb-specific T-cell response is unknown, nor is it clear if these return to normal levels. One reason for the lack of understanding of the relationship between these pathogens is the limited availability of sufficiently-sized populations of M.tb-infected patients and the clinical infrastructure to assess them. The assembled team has the appropriate expertise to address these issues and the cohorts of patients within a single joined-up health region.


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