Some Q&A About Tuberculosis Diagnosis During COVID-19 Pandemic

WHO is continuously monitoring and responding to tuberculosis (TB) prevention and care during the COVID-19 pandemic. Health services need to be actively engaged for an effective and rapid response to COVID-19 while ensuring that TB and other essential health services are maintained.

Are people with tuberculosis likely to be at increased risk of COVID-19 infection, illness and death?

While experience on COVID-19 infection in tuberculosis (TB) patients remains limited, it is anticipated that people ill with both TB and COVID-19 may have poorer treatment outcomes, especially if TB treatment is interrupted.
Older age, diabetes and chronic obstructive pulmonary disease (COPD) are linked with more severe COVID-19 and are also risk factors for poor outcomes in TB.
TB patients should take precautions as advised by health authorities to be protected from COVID-19 and continue their TB treatment as prescribed.
People ill with COVID-19 and TB show similar symptoms such as cough, fever and difficulty breathing. Both diseases attack primarily the lungs and although both biological agents transmit mainly via close contact, the incubation period from exposure to disease in TB is longer, often with a slow onset.

Do COVID-19 and tuberculosis spread in the same way?

While both tuberculosis (TB) and COVID-19 spread by close contact between people the exact mode of transmission differs, explaining some differences in infection control measures to mitigate the two conditions. TB bacilli remain suspended in the air in droplet nuclei for several hours after a TB patient coughs, sneezes, shouts, or sings, and people who inhale them can get infected. The size of these droplet nuclei is a key factor determining their infectiousness. Their concentration decreases with ventilation and exposure to direct sunlight. COVID-19 transmission has primarily been attributed to the direct breathing of droplets expelled by someone with COVID-19 (people may be infectious before clinical features become apparent). Droplets produced by coughing, sneezing, exhaling and speaking may land on objects and surfaces, and contacts can get infected with COVID-19 by touching them and then touching their eyes, nose or mouth. Handwashing, in addition to respiratory precautions, are thus important in the control of COVID-19.

Can tuberculosis and COVID-19 be tested on the same type of specimen?

The diagnostic methods for tuberculosis (TB) and COVID-19 are quite distinct and commonly require different specimens.
Sputum, as well as many other biological specimens, can be used to diagnose TB using culture or molecular techniques.
Tests for COVID-19 are done most commonly by nasopharyngeal or oropharyngeal swab or wash in ambulatory patients, but sputum or endotracheal aspirate or bronchoalveolar lavage may be used in patients with severe respiratory disease.

Should all people being evaluated for tuberculosis also be tested for COVID-19 and vice-versa?

Testing of the same patient for both tuberculosis (TB) and COVID-19 would generally be indicated for three main reasons, subject to the specific setting in each country:
1. clinical features that are common to both diseases; or
2. simultaneous exposure to both diseases; or
3. presence of a risk factor
As the pandemic advances, more people of all ages, including TB patients, will be exposed to COVID-19. The Information Note contains further considerations for simultaneous testing for the two diseases.

This article is quoted from WHO post on 11 May 2020.