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New Treatment Regimen for Latent TB Shows Promise

Prisoners constitute less than one percent of the nation’s population, yet according to statistics published by the Centers for Disease Control (CDC), they account for up to 6% of tuberculosis (TB) cases reported in the United States. [See: PLN, Aug. 2007, p.1].

The Indiana Department of Health, for example, found that 5 of 108 new cases of TB (4.6%) reported in the state in 2014 occurred in correctional facilities.

“Prison inmates are predominantly from poor and socioeconomically deprived sectors of society, usually where TB infections are high, and [they] often bring it with them to the prisons,” said Ken Severson, media director for the Indiana State Board of Health.

He noted that close prolonged indoor confinement, inadequate ventilation, frequent movement of prisoners, overpopulation and inadequate negative air pressure in areas used to isolate prisoners with active TB were contributing factors.

Dozens of prisoners at the Pendleton Correctional Facility filed a class-action lawsuit against the Indiana Department of Corrections in May 2015 over exposure to TB. They cited the Columbia Human Rights Review in their suit, which reported: “Outside of prison, TB does not spread that easily, but in prison, TB spreads much more easily because of overcrowding and poor ventilation.”

The CDC also lists as TB risk factors for prisoners both language barriers that interfere with access to health care and stigmatizing cultural perceptions that discourage diagnosis. Additionally, the high rate of HIV infection among prisoners means they are more likely to progress from latent TB – where the immune system is able to hold the infection in check – to active TB, a dangerous and infectious stage of the disease.

Tuberculosis is caused by an airborne bacterium that spreads to others nearby when a person with an active TB infection coughs. It usually infects and damages the lower lobes of the lungs. However, it can be encapsulated by the immune system before it reaches the lower lobes (latent TB), or – in rare cases – can enter the blood stream and attack internal organs such as the kidneys, spine and brain. Exposure to TB is easily detected by a skin test that uses a synthetic protein which mimics a portion of the TB bacterium but is incapable of causing the disease. Standard treatment for TB is a lengthy course of antibiotics, though antibiotic-resistant strains are emerging that are difficult to treat.

Some prison systems are diligent about testing all prisoners annually for TB. Combining testing with the prompt quarantine and treatment of infected prisoners can effectively eliminate the disease. But in less diligent systems, a single prisoner with TB has caused as many as 800 prisoners and guards to test positive for TB exposure.

In January 2017, corrections officials in Arapahoe County, Colorado reported that one prisoner had tested positive for TB, though those same officials described the risk of transmission as “very low.”

Two months later, another TB patient was identified at the King County jail in Kent, Washington, just outside Seattle. That prisoner had been in contact with 66 other people – both prisoners and staff – in the 100 days before he was diagnosed with the disease.

Fortunately, cases of active TB are dwarfed by the number of latent cases, which are traditionally treated with a nine-month course of antibiotics. That makes it difficult to complete treatment in jails, which typically have short-term transient populations. As a result, the CDC estimates that only a third of prisoners with latent TB finish the treatment regimen. In Santa Clara County, California the completion rate was just 18 percent.

However, a November 2016 report from Santa Clara County revealed the results of a study conducted at the county jail, which found a shorter treatment regimen – 12 weeks with two antibiotics versus 39 weeks using one – can be just as effective, while also more than quadrupling the treatment completion rate to 85 percent.

“To complete [traditional] treatment is very difficult because it takes too long,” said Maria Juarez-Reyes, assistant clinical professor at Stanford University and lead author of the clinical trial conducted at the Santa Clara County jail. “The average length of stay was three and a half months before [prisoners] were transferred or released.”

Upon their release, prisoners would receive information about local TB clinics where they could finish treatment, but the follow-up rate was “very, very low,” Juarez-Reyes noted.

The shorter treatment regimen was found not only to be just as effective as the longer traditional approach, but also to have a low incidence of adverse side-effects.

“This is really fantastic,” said co-author Neha Shah, who works with the Tuberculosis Control Branch of California’s Department of Public Health. “The implication is we can get more people through treatment, treat them effectively before they break down and get sick and can infect other people.”

The shorter treatment regimen for latent TB is now standard for the 4,000 prisoners in Santa Clara County’s jail system. Dr. Alexander Chyorny, who works at the Santa Clara Valley Medical Center, and who was another co-author of the study, said treatment completion rates have remained between 65 to 75 percent. Each county jail in California has its own protocol for treating latent TB, but the state’s health department is urging them to use the new three-month regimen with two drugs or a four-month regimen with one drug administered daily.

The Santa Clara County clinical trial was the most recent in a series of studies to report positive results from a shortened treatment regimen for latent TB, following one published in December 2011 in the New England Journal of Medicine and two more tallied by the CDC. In October 2015, the federal Bureau of Prisons adopted a 12-week, two-drug TB treatment protocol.

But the shorter regimen has yet to be adopted among the general population, where the CDC reports the standard treatment continues to rely on a nine-month protocol. In fact, the CDC has pointed out that a shorter regimen “does not replace” the longer treatment for latent TB, which it said is the “preferred regimen” for children under age 12, pregnant women and those taking anti-retroviral medications for HIV. 

Sources: Herald Bulletin, AIDS Foundation of Houston, Centers for Disease Control,,,,,,