A study published on the July 22 issue of the Journal of the
American Medical Association called for more aggressive action against
tuberculosis, after it had discovered an increase in the number of foreigners
in the US
infected with TB.
Although TB cases in the US dropped 45 percent between 1996
and 2006 (from more than 25,000 to less than 14,000), according to the US
Centers for Disease Control and Prevention’s statistics, there was a five
percent increase in TB cases among immigrant populations living in the US
during the same period, Dr. Kevin P. Cain head of the CDC’s Division of
Tuberculosis Elimination and lead author of the study said.
According to the study, 57 percent of all reported TB cases
in the US
are among foreign-born individuals. Of those, more than half were among
immigrants from sub-Saharan Africa and Southeast Asia, even though they make up
less than a quarter of the foreign-born contingent.
For the study, Dr. Cain studied data from the US National TB
Surveillance System, which registered 46,970 cases among foreign-born persons
in the US
between 2001 through 2006. Of those, 12,928 (28 percent) were among those who
had entered the country within two years.
Moreover, TB cases were four times higher among foreign-born
immigrants than among US-born people even for those who had been living in the US for
more than 20 years, the study found.
Rates of TB varied substantially by country and region of
origin. For example, individuals born in countries of sub-Saharan Africa had
annual case rates of greater than 250 per 100,000 persons during the first two
years after entering the US.
Annual rates were greater than 100 per 100,000 persons for individuals born in
Central America, Eastern Europe, the Pacific
Islands and South, East and central Asia. By contrast, people born in Western
Europe, Canada, Australia, and New Zealand presented lower risk of
TB of less than 10 per 100,000.
Dr. Cain said it is impossible to test the 37 million
foreign-born individuals currently living in the US. However, the findings would
help officials make better use of TB control resources.
“We believe that this is helpful
because, while it might not be possible to test and treat all foreign-persons
for latent TB, if programs can try to focus on the highest risk groups and can
reach out to the populations that need this testing and treatment the most,
then they'll have a greater chance of preventing as many cases as possible for
the number of tests that they are able to do,” he said.
Dr. Cain said that screening
immigrants and refugees from the Philippines
and Vietnam would have
detected almost half the average 250 TB cases brought into the US annually
between 2001 and 2006.
In order to prevent TB cases, Dr. Cain suggested that
immigrants should receive overseas diagnosis and treatment prior to
immigration, especially those coming from the countries with the highest rate
of infection. Another way to curb TB rates would be to find and treat latent TB
infections. In these cases, germs are present but the body is able to fight off
symptoms. The infection becomes active and able to spread once the immune system
begins to weaken as we get old or in case of a serious disease.
However, he added that “as long as TB is out of control
globally, as it is, this will be a problem in the US. If you breathe, you’re at risk
for TB. This can affect anyone.”