With the recent commemoration of World TB Day, the CDC reported that tuberculosis continues to decline in the United States, but not on a pace to reach the goal of tuberculosis eradication.
“In 2016, a total of 9,287 new tuberculosis cases were reported in the U.S.,” the CDC reported.1 “This provisional count represents the lowest number of U.S. TB cases on record and a 2.7% decrease from 2015. The 2016 TB incidence of 2.9 cases per 100,000 persons represents a slight decrease compared with 2015 (-3.4%). However, epidemiologic modeling demonstrates that if similar slow rates of decline continue, the goal of U.S. TB elimination will not be reached during this century. Although current programs to identify and treat active TB disease must be maintained and strengthened, increased measures to identify and treat latent TB infection (LTBI) among populations at high risk are also needed to accelerate progress toward TB elimination.”
That means employee health professionals must remain vigilant with TB testing programs for healthcare workers, with the frequency determined by using the standard CDC risk assessment. (View the CDC’s TB risk assessment worksheet at: http://bit.ly/2olPLY7.)
A Legendary Killer
Poet John Keats, gunfighter Doc Holliday, First Lady Eleanor Roosevelt. All died of an ancient malady once called consumption — because it seemed to “consume” its wan sufferers as it took the life from them breath by bloody breath.
TB is a largely treatable disease that still manages to kill millions worldwide, can lie dormant for years until a carrier becomes immune compromised, and has developed strains highly resistant to drug therapy. Impoverished crowded communities in Asia and Africa still suffer the major toll of TB — and, of course, any disease in the world is but a plane ride away.
“TB cases continue to occur in every state and region in the United States,” the CDC reports. “Analysis suggests that eliminating TB will require a dual approach: strengthening existing TB programs/systems to diagnose and treat active TB disease, and intensifying efforts to identify and treat latent TB infection among those who are infected with TB bacteria but are not yet sick.”
The CDC estimates that over the last two decades, TB control efforts have prevented as many as 300,000 people from developing the disease, saving more than $6 billion in costs.
“Unfortunately, these efforts alone will not be sufficient,” the CDC notes. “More than 85% of U.S. TB cases are associated with reactivation of latent TB infection, often acquired years earlier. It’s estimated there are up to 13 million people living in the U.S. with latent TB infection. … While they do not have symptoms and cannot spread the bacteria to others, 5% to 10% of them will eventually develop active TB disease if left untreated.”
TB has plagued humankind for thousands of years because it is both patient and mutable. It is the ultimate opportunistic infection and can demonstrate high levels of resistance if drugs are not administered properly and taken with full compliance.
“Treating a single person for drug-susceptible TB disease costs about $18,000 — some 36 times more than the $500 it costs to proactively treat a person for latent TB infection,” the CDC reports. “The cost for treating drug-resistant TB disease is even higher, ranging from $154,000 to $494,000,” up to nearly 1,000 times treatment costs for a latent TB infection.
Drug-resistant TB
In 2015 data — the most recent available — 88 cases of multidrug-resistant TB occurred in the U.S., comprising 0.4% and 1.2% of culture-confirmed TB cases among U.S.-born and foreign-born persons, respectively, the CDC notes. Among those 88 multidrug-resistant TB cases, 72 (81.8%) occurred in people with no reported history of TB disease. Fortunately, only one case of extensively drug-resistant TB — which can be virtually untreatable — occurred in the U.S.
State-specific TB incidence for 2016 ranged from 0.2 cases per 100,000 persons in Wyoming to 8.3 in Hawaii, with a median state incidence of 1.9. California, Florida, New York, and Texas reported more than 500 cases each in 2016, accounting for 51% of reported cases nationwide. Seven other states and Washington, DC exceeded the national TB incidence rate: Alaska, Arkansas, Georgia, Maryland, Minnesota, New Jersey, and North Dakota.
“Among 9,287 TB cases reported in 2016, U.S.-born persons accounted for 2,935 (31.6%) cases, and 6,307 (67.9%) cases occurred among foreign-born persons,” the CDC reports. “TB incidence among U.S.-born persons (1.1 cases per 100,000) decreased 8.4% from 2015. Incidence among foreign-born persons (14.6 cases per 100,000) decreased 3.2% from 2015, but was approximately 14 times the incidence among U.S.-born persons.”
In 2016, four of the top five countries of origin for foreign-born people with TB disease were considered high TB burden countries by the World Health Organization: China, India, Philippines, and Vietnam. People from these countries accounted for 36% of incident TB cases among foreign-born people in U.S.
“Because approximately 90% of TB cases in foreign-born persons in the U.S. are attributable to reactivation of LTBI, targeted testing for and treatment of LTBI among foreign-born persons from countries with high TB prevalence could be an effective strategy to decrease TB incidence,” the CDC concludes. “The current recommendation … to test persons at increased risk regardless of length of time in the U.S. is in keeping with evidence that reactivation of LTBI remains a substantial concern, even in foreign-born persons who have lived in the United States for many years.”
REFERENCE
- CDC. Tuberculosis — United States, 2016. MMWR 2017;66(11):289–294
With the recent commemoration of World TB Day, the CDC reported that tuberculosis continues to decline in the United States, but not on a pace to reach the goal of tuberculosis eradication.
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