Immigrants traditionally get blamed for a country’s ills and historically they have been feared for their ability to bring disease as well. The recent cases of the traveling lawyer (and here, passim)and the Mexican businessman with TB raised concerns that tuberculosis would be brought to the US or other low TB incidence countries by immigrants or travelers from countries where TB was prevalent. Now a new study from Norway suggests this doesn’t happen:
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 to researchers in Norway, who analyzed the incidence and genetic origins of all known cases of TB in the country between 1993 and 2005. Their results were reported in the first issue for November of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.
After gathering all available cultures from the identified cases and eliminating samples suspected of being contaminated in the lab, the researchers examined 2,173 cases of TB in the country over 12 years. They tracked outbreaks among native-born citizens and immigrants, and analyzed the genetic strain of each confirmed case using cultures obtained through patient samples at 14 laboratories that service the entire country.
They 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. (Infection Control Today)
During the twelve year study period there continued to be a lack of similarity between the infections among natives and those among immigrants. Nor was there any evidence of a clustering of a strain indicative of an outbreak. In ten imported cases TB was passed on to more than 5 cases within 5 years. This was not considered a significant threat to TB control. Said another way, indigenous TB can be eliminated without being seriously challenged by importation of cases from immigrants from high incidence areas.
So that’s the good news — for Norway. But the US isn’t Norway. We don’t have a national health system. The accompanying editorial by Dr. Kevin Schwartzman of McGill University in Montreal, who was not part of the study, noted that this was an important strength of the Norwegian success:
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 Schwartzman. “By ensuring access to TB care and public health programs for all, Norwegian authorities are controlling TB and preventing transmission.”
I know I am always harping on the importance to US health of a national health service. That doesn’t make it any less true. You can like it or not. Frankly I can afford some extra taxation more than I can afford TB.
But maybe that’s just me.