Dissecting Tuberculosis in the US

Today the CDC released the latest numbers on tuberculosis in the US and it is all good news with a couple of caveats.

Overall, there's been a 2.2% decline in tuberculosis in the US with just 9412 cases reported in 2014. This translates to a rate of 3 cases per 100,000 people which is extremely low but not yet at the goal of 1 case per 1,000,000. Indeed, recent news stories have shown that the risk of tuberculosis still exists with an active case diagnosed in a Pittsburgh school; a similar incident in Kansas caused 27 students becoming skin test positive, indicating they contracted latent TB.

When one dissects the rate of 3 cases per 100,000 there are several important and ominous findings: 

  • The rate of tuberculosis is 13.4 times higher in those foreign born when compared to those born in the US; 66.5% of cases are in this group
  • Asians are the ethnic group with the highest burden of cases in the US
  • Hawaii is the state with the highest rate of tuberculosis in the US
  • California, Florida, New York, and Texas account for 50.9% of all US cases in 2014
  • 6.3% are HIV-positive
  • Just 1.3% of cases (in 2013) were multi-drug resistant

Interpreting these numbers, it becomes clear that tuberculosis is a waning problem in the US when looked at in aggregate. However, looking at the data in all its granularity it becomes clear that the final push for tuberculosis control will be in finding foreign-borne individuals with latent tuberculosis--immigrants are screened for active tuberculosis via culture and chest x-ray in their home country--and placing them on treatment to prevent reactivation. Such an effort is daunting as many of the individuals in these communities are not readily available to public health and medical officials, but placing them on treatment is the means to eliminate tuberculosis from the US.