Tuberculosis Outbreak in a State Prison System - Washington, 2021-2022

Area of Science:

• Public Health
• Infectious Diseases
• Epidemiology

Background:

• No tuberculosis (TB) cases were reported in Washington state prisons from 2014-2020.
• A notable resurgence of TB occurred between July 2021 and June 2022, with 25 cases identified among incarcerated or formerly incarcerated individuals.

Purpose of the Study:

• To investigate a recent outbreak of tuberculosis within the Washington state prison system.
• To identify the source, extent, and contributing factors of the TB outbreak.

Main Methods:

• Phylogenetic analysis of whole genome sequencing data from Mycobacterium tuberculosis isolates.
• Contact tracing among incarcerated residents and staff across multiple state prisons.
• Review of TB screening protocols and potential barriers to timely diagnosis.

Main Results:

• Whole genome sequencing confirmed a single outbreak, with closely related Mycobacterium tuberculosis isolates from 11 patients.
• Over 3,000 contacts were identified, and 244 individuals were diagnosed with latent TB infection (LTBI).
• The outbreak is the largest in Washington state in two decades, exacerbated by suspended TB screening and fear of isolation.

Conclusions:

• The TB outbreak in Washington state prisons was facilitated by the suspension of routine screening and fear of isolation among residents and staff.
• Close collaboration between the Washington State Department of Corrections and Department of Health is crucial for outbreak containment and prevention.
• Enhanced TB surveillance and prompt diagnosis are essential to control infectious disease transmission in correctional facilities.