Washington’s Largest TB Outbreak in 20 Years Began in Its Prisons, 2021–2022

From 2014 to 2020, the Washington State prison system reported no tuberculosis (TB) cases. Then, from July 2021 to June 2022, 25 people incarcerated or formerly incarcerated in two state prisons developed TB disease — the largest TB outbreak in Washington in 20 years and the first ever recorded in the state's Department of Corrections (WADOC). Randy M. Stalter of CDC and colleagues at the Washington State Department of Health (WADOH), WADOC and CDC reported on it.

How it unfolded

• July–August 2021: At "facility A," one incarcerated person was diagnosed with TB disease and two with latent TB infection (LTBI). A search found one more case of TB disease and 27 more people with LTBI. None of them showed signs of being highly contagious, suggesting someone with undiagnosed, infectious TB elsewhere in the system — or recently released.
• December 2021–January 2022: Three people at a second prison, "facility B," were diagnosed, one of them already released into the community and another transferred to a third prison, "facility C."
• February 7, 2022: A CDC team arrived to help.

Because staff and residents move between prisons and some were released, the investigation reached all 12 WADOC prisons and most of Washington's local health jurisdictions.

What investigators found

A contact was anyone in the same place on the same day as a patient during the patient's infectious period. CDC helped map contacts using WADOC data on where people slept and moved each day, staff schedules and clinical risks.

Outbreak TB cases over time. Credit: CDC, MMWR.

The response

• Screening of residents and staff at facilities A, B and C, with skin tests for most U.S.-born people and blood tests (interferon-gamma release assays) for most born abroad.
• Chest X-rays and clinical evaluation for anyone newly infected, previously positive or with symptoms; isolation while being evaluated; 4–6 months of treatment for TB disease.
• For LTBI, the preferred 3-month isoniazid–rifapentine regimen — but national shortages of rifamycin drugs delayed treatment for some. People with weakened immune systems were offered 9 months of isoniazid instead, to avoid delay; the longer regimen, with more risk of liver toxicity, was reserved for those at high risk.
• Information sessions on TB for residents, their families and staff.

Why it spread

1. Paused screening. Annual TB testing had been suspended, in places for up to 2 years, as WADOC diverted resources to COVID-19.
2. Missed diagnoses. Clinicians inside and outside the prisons did not promptly diagnose TB in two people who had symptoms — one of them transferred from facility A to facility B while contagious. TB's rarity before the outbreak, symptoms that overlap with COVID-19, and a simultaneous COVID-19 outbreak may all have played a part.
3. Fear of isolation. Residents feared physical and social isolation, and staff feared isolation and lost work hours, discouraging them from reporting symptoms or agreeing to testing.

Preventing the next one

The authors call for fully restoring routine TB symptom screening and testing in prisons, raising TB awareness among residents, staff and medical personnel, adopting policies that encourage symptom reporting and testing, and building data systems able to handle contact investigations on this scale — something state prisons are not always equipped or funded to do. Close collaboration between corrections and health departments will be key.

Sources

Based on Stalter RM, Pecha M, Dov L, et al., "Tuberculosis Outbreak in a State Prison System — Washington, 2021–2022," MMWR, Centers for Disease Control and Prevention; a work of the United States government in the public domain.