150 people require TB testing after Microsoft vendor diagnosed with active tuberculosis

REDMOND, Wash. -- About 150 vendors for Microsoft will require TB testing after one vendor was recently diagnosed with active tuberculosis, according to King County Public Health.

Here's what the public health agency had to say about tuberculosis and how it spreads:

TB is not easy to spread

TB is an infectious disease caused by bacteria that are passed from person to person through the air. TB is not easily spread; it’s much harder to spread than the cold or flu. It typically takes repeated and prolonged exposure in a confined indoor space to become infected with TB. Even in households with a person with contagious TB disease, only about 1-in-3 close household contacts become infected.

Active disease different from latent TB

Unlike active TB disease, people with latent (or dormant) TB infection can’t spread it to others and are not ill with the disease. Approximately 100,000 people in King County have latent TB infection. While they aren’t contagious now, they could potentially have active TB in the future and also infect others. Approximately one in 10 people with latent TB infection will develop active TB disease in their lifetime.

Details on the evaluation

An evaluation of exposures identified nearly 150 vendor employees who were in close contact with the person with TB disease for a long enough period of time that testing for TB infection is recommended as a precaution. The vendor companies are reaching out to their affected employees to notify them. Public Health has been on site this week to evaluate and test people who were exposed.

Treatment for TB

The vendor with active TB disease is currently receiving treatment. Most cases of active TB are readily treatable with antibiotics that are commonly available; treatment typically takes six to nine months. Drug-resistant strains require different antibiotics and may include a longer course of treatment (up to two years).

To become cured, a patient must complete the entire treatment, even after they are no longer infectious. If the treatment is interrupted before the bacteria are completely eliminated, TB can develop drug-resistance and become much harder to treat.

If any staff are identified to be infected with latent TB, they may be recommended for treatment, so that they do not develop the disease in the future.

More about TB

TB usually affects the lungs, but can affect lymph nodes, bones, joints, and other parts of the body. A person with active TB in the lungs can spread the disease by coughing or sneezing. In King County, 134 new cases of TB disease were reported in 2019.

To learn more about signs, symptoms, and transmission of TB, visit the U.S. Centers for Disease Control and Prevention’s TB website.