TB at an all-time low in United States

April 2005

U.S. rates of tuberculosis (TB) reached an all-time low in 2004, however the rate decline compared with years past was one of the smallest in more than a decade.

According to the CDC’s latest data from the National TB Surveillance System, there were 14,511 TB cases reported in 2004. The overall case rate – 4.9 per 100,000 people – was the lowest ever recorded since 1953, when national reporting began.

Despite these findings, the CDC said “TB continues to exact a severe toll on many U.S. communities.”

While the decline in case rate from year to year has decreased on average 6.8%, between 2003 and 2004 the decline was only 3.3%, according to the data.

Cases increased in 17 states, but decreased among 58.8% of the states. The rate did not change for three states between 2003 and 2004. Seven states reported more than 400 cases each last year, collectively accounting for more than half of the national total.

Foreign-born individuals had higher rates of TB and are most affected.

Racial and ethnic disparities

In 2004, minorities had rates of TB significantly higher than the overall U.S. average, according to the CDC surveillance data.

For the first time, there were more frequent cases of TB among Hispanic people than any other ethnic group.

The number of cases among this group increased 1.2%; from 4,109 in 2003 to 4,160 in 2004. However, the rate among Hispanics decreased slightly from 10.3 in 2003 to 10.1 in 2004.

Among Asians, blacks and whites, the case numbers and rates both decreased.

TB case rates among Asians was 20 times higher than that among whites (26.9/100,000 and 1.3/100,000, respectively). Blacks (11.1/100,000) had rates 8.3 times higher than whites, the CDC reported, and Hispanics (10.1/100,000) had rates 7.5 times higher.

In 2004 6,637 TB cases were reported among U.S.-born citizens, a decrease of 3.7% compared with 2003 and a decrease of 61.9% compared with 1993.

People born outside the United States accounted for 53.7% (7,701 cases) of all new TB cases in 2004.

Foreign-born individuals were nearly nine times more likely to have TB than those U.S. born citizens (22.5/100,000 compared to 2.6/100,000). The majority of Hispanics (74%), Asians (95.4%), and blacks (26.5%) reported to have TB in the U.S. in 2004 were foreign-born.

However, the TB rate among U.S.-born people declined 64.6% over the past 12 years and among foreign-born people it declined 33.9%.

According to the report, during 2004, 58.8% (30) states reported a decline in cases from 2003, however, 17 states and Washington reported an increase. Three states, Hawaii, Oregon, and Delaware, saw no changes. Seven states, California, Florida, Georgia, Illinois, New Jersey, New York, and Texas, bear more than half the total burden of TB disease in the nation, reporting over 400 cases each in 2004 and collectively accounting for 59.9% of the national case total (8,689 cases).

However, of these seven, only Texas and Florida increased in case rates (4% and 1%).

Patients completing treatment in a timely manner is an important measure of the effectiveness of TB control efforts, the CDC said.

The most recent treatment-completion data from 2001 show that 81.4% of U.S.-born and 80.4% of foreign-born TB patients completed therapy within one year.

There was no significant variation in treatment completion by race, the data indicates.

Cases of multidrug-resistant TB (MDR-TB) has also declined sharply in the United States over the past decade.

In 2003, the most recent year resistance rates were reported, 114 people reported MDR-TB, a 76.5% decline since 1993. Of these, 28 (0.6%) were U.S.-born citizens and 86 (1.4%) were born in other nations, a 91.6% and 42.7% decline in drug-resistant TB cases from 1993.

Previous data suggest little variation in rates of treatment completion by country of origin. Therefore, the greater proportion of cases of drug-resistant TB among foreign-born individuals is likely the result of TB infection in the person’s country of origin, where MDR-TB rates are higher compared to the United States, the CDC said.

Health officials hope to increase treatment completion rates to 90% by 2010.

More than one-third of the population worldwide is infected with the TB bacterium, and TB disease remains one of the world’s leading causes of disease and death. Eight million people become ill with TB and 2 million people die from it each year.

“Even though preventable and treatable, TB remains a serious airborne disease – one with the ability to adapt, grow stronger, and travel from one country to another as easily as people do,” the CDC said. The CDC acknowledged the need to strengthen global partnerships to address the disease among those hardest-hit. Efforts include improving overseas screening for immigrants and refugees, and testing recent arrivals from high-incidence countries for latent infection. The notification system that alerts local health departments about the arrival of immigrants who are known or believed to have TB is slated to be improved as well.

The CDC plans to collaborate with public health teams in Mexico to improve TB control among those who cross the U.S.-Mexico border.

Public health officials are working to ensure that adequate local resources are in place in communities with the greatest burden of TB. Such efforts include funding demonstration projects to address TB among blacks and building the capacity of front-line health care providers to ensure complete TB treatment is available.

For more information:

• www.cdc.gov/nchstp/tb/WorldTBDay/2005
• CDC. Trends in Tuberculosis – United States 2004. MMWR. 2005;54(10):245-249.
• CDC. Reported Tuberculosis in the United States, 2003. Atlanta, GA: U.S. Department of Health and Human Services, September 2004.