TB at record low, waiting for us to claim victory

January 12th, 2015

“The past is not dead. In fact, it's not even past.” --William Faulkner

Was it not so long ago in a universe strikingly similar to ours that federal regulators were calling for a comprehensive national regulation to protect health care workers from tuberculosis?

Recently the CDC National Tuberculosis Surveillance System reported that the rate of new TB cases in 2011 was the lowest since reporting began in 1953. A total of 10,521 cases were reported in 2011 for an incidence of 3.4 cases per 100,000 population — a decrease of 6.4% from the previous year.

Before we start planning a public health victory parade and talk about complete TB eradication, it’s best to reread that quote above by Faulkner. TB is nothing if not patient, a great opportunist and a classic opportunistic infection that has risen time again after last rites have been administered. Thus we have that aforementioned resurgence of TB in the late 1980s and early 1990s when a series of hospital outbreaks triggered the failed rule-making attempt by OSHA.

TB remains a global problem so it remains a threat to any given country that raises the victory flag of complacency. Even in the otherwise encouraging U.S. data, 16 states and the District of Columbia actually had higher rates in 2011 than in 2010. Four states — California, Florida, New York, and Texas -- accounted for approximately one-half of all TB cases reported in 2011. Among the 81% of cases for whom their HIV status was known, 7.9% were seropositive.

A total of 109 cases of MDR TB were reported in 2010 (the most recent year for which complete results were available), representing 1.3% of those tested, a figure unchanged from the previous year. Among individuals with no past history of treatment for tuberculosis, the percentage of MDR TB has remained stable at approximately 1.0% since 1997. Among those with a previous history of TB, the proportion with MDR TB was approximately 4 times higher. Foreign-born individuals accounted for 82.6% of the total MDR TB cases in 2010 and 4 cases of XDR TB have were reported in 2011, all occurring in foreign-born. Though we are seeing only a smattering of the pan-resistant XDR-TB, it is a strain that is loose in the world and thus a possible disease in our future.

While overall TB rates are decreasing in the U.S., TB continues to be a significant problem among the foreign-born. Almost 80% of cases among the foreign-born were diagnosed two or more years after entry into the U.S., suggesting that most were the result of reactivation of latent infection that had been acquired in their native lands. The genie may be back in the bottle, but we should continue to keep a firm grip on the cork. The history of TB – sometimes called “the U-shaped curve of concern” -- is that once the disease declines and the attendant public health dollars bottom out with it, the inevitable resurgence begins.