Immigrants from countries with high rates of tuberculosis who move to countries of low TB incidence do not pose a public health threat to native citizens, according the November issue of the American Journal of Respiratory and Critical Care Medicine.
After examining 2,173 cases of TB in their own country over 12 years, Norwegian researchers found little evidence to support the belief that immigrants from countries with high TB incidence present a public health threat to non-immigrant natives in low-incidence countries. Instead, the researchers documented an increase in number of strains in immigrants, but a decrease in the number and incidence of native infections, suggesting that while immigrants from high-TB regions do bring with them more strains of TB, they do not significantly contribute to the spread of TB within native-born populations of low-incidence countries.
“Immigrants have been accused of spreading TB. However, the current study demonstrated that the importation of M. tuberculosis, over 12 years, did not generate significant negative effects on the transmission of TB in a country that was considered to be in the elimination phase of this disease,” wrote lead researcher, Ulf R. Dahle, PhD, of the Norwegian Institute of Public Health.
This finding is especially relevant in the current climate of increased public anxiety over high profile cases of TB-carrying travelers including Andrew Speaker, the American who traveled extensively while infected with multidrug-resistant TB disease, and Amado Isidro Armendariz Amaya, a Mexican businessman reported to have crossed the U.S. border 76 times, carrying multidrug-resistant TB.
Ultimately, the strategies used to control TB are more important to public health than immigration. “The take-home message is not one of blame or stigmatization—quite the opposite,” said Kevin Schwartzman, MD, MPh, of McGill University, a researcher unaffiliated with the study, in an accompanying editorial in the same issue of the journal. “By ensuring access to TB care and public health programs for all, Norwegian authorities are controlling TB and preventing transmission.”