Tuberculosis, Like Covid, Spreads by Breathing, Scientists Report

"As much as 90 percent of TB bacteria released from an infected person may be carried in tiny droplets, called aerosols, that are expelled when a person exhales deeply, the researchers estimated.

 

The findings were presented on Tuesday at a scientific conference held online.

 

The finding helps explain why tightly packed indoor spaces, like prisons, often are breeding grounds for TB, as they are for Covid. And the research suggests that some of the methods used to limit coronavirus transmission — masks, open windows or doors, and being outdoors as much as possible — are important in curtailing TB.

 

 A single cough can expel more bacteria than a single breath. But if an infected person breathes 22,000 times per day while coughing up to 500 times, then coughing accounts for as little as 7 percent of the total bacteria emitted by an infected patient.

In so-called tidal breathing, inhalation opens up tiny air sacs in the lungs, and then exhalation carries the bacteria from the lungs via aerosols. Because of their smaller size, aerosols released by tidal breathing can stay afloat in the air for longer and travel further than droplets emitted by a cough.

Still, experts said, the finding does suggest that physicians shouldn’t wait for TB patients to arrive at clinics with a severe cough and weight loss, the telltale symptoms.

We just need to screen the entire population, just like you would do if you’re looking for a lot of Covid."