'Do no harm'? HCWs need vigilance on TB

HCW exposes patients at NYC hospital

In January, a health care worker who worked in the maternity ward, neonatal intensive care unit, newborn nursery and psychiatric ward of St. Barnabas Hospital in New York City was diagnosed with active tuberculosis. She had exposed 532 patients, including more than 200 of them newborns, and about 100 co-workers.

Two months later, only about half of her fellow employees had come for TB screening related to the exposure. The difficulty in getting health care workers to respond to the exposure is evidence of a broader problem: Complacency about TB infection among health care workers.

"A lot of [foreign-born] health care workers believe they are going to be positive because of the BCG vaccine they have received in childhood," says Sonal Munsiff, MD, director of the Bureau of TB Control at the New York City Health Department. "They don't value the results of the skin test."

Health care workers also are aware that few people with TB infection progress to active disease. About 5% will develop active TB in the first two years after infection and another 5% will experience the disease over a lifetime.

Although the number of cases may be small, the progression to active disease has huge implications both for the individual health care worker and the hospital. In 2004, a nurse at Chesapeake General Hospital ignored her symptoms for months. By the time she was diagnosed, treatment was no longer effective and she died. Meanwhile, she had exposed thousands; the hospital tested about 1,600 patients, visitors, volunteers, and 280 co-workers.

"When [a health care worker develops active TB], it can be potentially catastrophic, not only to the health care worker but also to the patients," says Timothy Sterling, MD, an infectious disease expert and associate professor of medicine at the Vanderbilt University Medical Center in Nashville, TN.

If the health care worker is caring for especially vulnerable patients, such as HIV, oncology, or transplant patients, "then there's a greater potential for real harm."

And, of course, physicians and other health care workers pledge to "do no harm." Sterling and his colleague, David W. Haas, MD, urged health care workers to follow the guidelines of the Centers for Disease Control and Prevention and consider treatment for latent TB infection.1

Educate HCWs about risks, benefits

Employee health invests considerable resources in making sure all employees receive an annual TB screening. They also need to take a leading role in educating employees and helping them determine if they need treatment for latent TB infection, says Munsiff.

"They can be more rigorous about educating and informing about the risks and benefits
of LTBI treatment," she says. If they decline treatment, that should be documented in their employee health record. Employees also may be asked to sign a waiver, as they do if they decline hepatitis B vaccine, she suggests.

"The greatest risk of developing TB is in the first year after infection," says Munsiff. "The earlier treatment is given, the lower the risk the person will have disease."

Not all health care workers will be candidates for LTBI treatment. A history of liver injury or excessive alcohol intake is a contraindication, and patients with active hepatitis or liver disease require close monitoring if they undergo treatment. The CDC guidelines also state that most health care workers "do not have the risk factors for progression to disease that serve as the basis for the current recommendations for targeted testing and treatment of LTBI. The majority of health care workers in the United States do not provide care in areas in which the prevalence of TB is high."2

HIV, organ transplant or other immunosuppressed individuals should receive the treatment. CDC also recommends LTBI treatment for people who have lived in a country with a high incidence of TB, which would include many foreign-born health care workers.

Yet foreign-born health care workers may be reluctant to take treatment because they attribute their positive skin tests to BCG vaccination in their childhood.

Some hospitals have begun using the whole-blood assay such as QuantiFERON-Gold as a confirmatory test for positive tuberculin skin tests. QuantiFERON does not react to BCG and may be more readily accepted as a "true positive" by foreign-born health care workers.

But CDC does not recommend the dual use of the tests. "It's not clear what the scores mean if one test is positive and one test is negative," says Phil LoBue, MD, associate director for science in the Division of Tuberculosis Elimination. "[If] you've chosen to believe the QuantiFERON over the skin test, why are you even doing the skin test to begin with?"

LoBue acknowledges that it may be hard to convince someone to take medication for latent infection daily for nine months when they are asymptomatic. But they should be advised that adverse events from the medication (isoniazid) are rare, and that the treatment is effective in preventing latent infection from progressing to active disease, he says. "In general, the benefits still outweigh the risk," he says.

Meanwhile, CDC is sponsoring a study of the effectiveness of a weekly dose of rifapentine for 12 weeks, compared to the traditional daily, nine-month treatment. Researchers hope to enlist 8,000 patients in the study. Clearly, the shorter regimen would be more tolerable. "We're looking at several more years before we have the answer [as to its effectiveness]," LoBue says.

Annual screen may not catch symptoms

If health care workers with positive TB screens decline treatment for LTBI, they are given annual health screens and asked to report any TB-like symptoms. Unfortunately, initially TB can seem like a common respiratory virus.

"It's definitely not uncommon for all kinds of TB patients to be sick for several weeks before they realize they need medical attention," says Munsiff. "It's a slowly progressing disease for many people."

That is an important message to convey in annual TB education. Health care workers with LTBI need to seek medical evaluation if they develop symptoms of TB, which include a cough lasting more than three weeks, bloody sputum, loss of appetite, unexplained weight loss, night sweats, hoarseness, fever, fatigue, or chest pain.

Those who decline treatment for LTBI will have to have a heightened awareness, says LoBue.

"Given the current tools and technologies, there is no perfect screening system that can guarantee there will be no cases of TB in health care workers," he says.

References

1. Sterling TR and Hass DW. Transmission of Mycobacterium tuberculosis from health care workers. N Engl J Med 2006; 355: 118-121.

2. Jensen PA, Lambert LA, Iademarco MF, et al. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings, 2005. MMWR 2006; 54:1-141.