Concurrent Tuberculosis and COVID-19 Testing from a Single Sputum Specimen for Enhanced Disease Detection

Background/Objectives: Both tuberculosis (TB) and SARS-CoV-2 share similar symptoms and transmission routes. In early 2021, USAID and Stop TB Partnership recommended an integrated approach for simultaneous COVID-19 and TB testing in high TB burden countries, using a nasopharyngeal swab and sputum for individuals with respiratory symptoms. We extended this in a clinical evaluation, testing a single sputum for both SARS-CoV-2 and Mycobacterium tuberculosis complex (MTBC) at two healthcare facilities in South Africa. Methods: A total of 2274 individuals were screened for enrolment. Eligibility included the presence of symptoms suggestive of either TB or COVID-19 infection, close contact with a person with TB, TB diagnosis in the last two years or a person living with HIV. Sputum from 1032 participants were tested on the Xpert Xpress SARS CoV-2 assay (Xpress) using a swab capture method while residual sputum was tested on the Xpert MTB/RIF Ultra assay for MTBC and rifampicin-resistance detection. Results: The Xpress assay detected SARS CoV-2 in 183/1032 (18%) participants, TB was detected in 35/1032 (3%) participants and 10/1032 (1%) participants were co-infected with TB and COVID-19. Conclusions: The study findings underscore a substantial identification of TB and Rifampicin-resistant TB that would have been missed if bi-disease testing was not performed. In addition, the sputum swab capture method for SARS-CoV-2 detection showed substantial agreement with routine testing.