Community involvement is critical to control foreign-born TB problem

Infection screening programs should target recent arrivals

A national group of TB experts has issued marching orders to tuberculosis control divisions across the land: Focus on foreign-born residents.

In "Recommendation for Prevention and Control of Tuberculosis Among Foreign-Born Persons" (Morbidity and Mortality Weekly Report, R&R, Vol. 47, Sept. 18, 1998), a national working group last month called on TB controllers to develop detailed profiles of foreign-born groups in their districts, target high-risk groups for screening, and form partnerships with community-based organizations (CBOs).

"Lots of programs are already doing some very innovative and exciting things, which they can share with the rest of us," says Nancy Binkin, MD, MPH, associate director for International Activities at the Centers for Disease Control and Prevention’s (CDC) Division of TB Elimination and a member of the working group. "But many other states are just now beginning to confront the problem [of the foreign-born] and will need to develop resources." (See related stories on TB control programs under way in Mississippi, Seattle, and Boston, pp. 123-125.)

Already, foreign-born cases make up 39% of the total nationwide; within the next three to five years, they may account for half of all U.S. cases, says Binkin. "We’re coming down very, very quickly in our U.S.-born cases but not really declining in the number of foreign-born cases," she says. "Ultimately, the foreign-born will become the principal focus for TB activities in this country."

New role: Planners and directors

One point that leaps out from the MMWR article is the enormity of the pool of latently infected foreign-born persons — about 7 million. As clinicians in many parts of the country meet their first priority — to get active cases and contact investigation under control — they are beginning to shift their focus toward providing preventive therapy, Binkin says.

Programs that target the foreign-born, however, will have to rely on help from outsiders in a way that programs aimed at home-grown TB cases have not, experts say. Instead of trying to play all of the instruments at once, so to speak, future TB control divisions will act more like orchestra conductors, providing direction, support, training, and supplies to CBOs, which will be doing a lot of the actual work themselves. Or, as the MMWR report says, "Emphasis should be on the community planning role of the health department and the implementation roles of other providers."

The shift toward forming more partnerships with CBOs is critical for two reasons, according to Binkin:

1. CBOs will provide the extra hands needed to extend the reach of health departments.

2. They will engender trust by providing the cultural and linguistic compatibility foreign-born populations require.

In addition to forming partnerships, TB controllers must carefully target groups for preventive therapy. "We’re really putting a lot of emphasis on this point: Don’t screen unless you’re planning to give preventive therapy," Binkin says. "If you don’t have the facility, the staff, and whatever else it takes to get people through therapy, don’t screen at all."

Infection screening programs should begin by targeting recent arrivals, which the working group report defines as those who’ve been here for five years or less. Among most groups from high-prevalence countries, after five years, "we’ve found that risk for reactivation starts to go down, especially in younger age groups," she says. "So we’ve set five years as the limit at which we might want to be actively screening people."

Demographic trends color a striking new picture of TB control. In 1996, the United States granted permanent residency status to 915,900 people. Added to that are an estimated 275,000 undocumented aliens who arrive each year. All told, 9% of the nation’s population, 24.6 million people, is foreign-born.

The composition of the foreign-born is shifting, the report adds. Of the two largest pools of immigrants — Latin-American and Asian — the latter is gaining steam. Thus, in 1994, 24% of all foreign-born persons in the United States were Asian; the following year, the proportion of Asians made up 37% of new arrivals.

The report also underscores the concentration of foreign-born populations in California, which claims 34% of the total pie; with smaller pieces (ranging from 5% to 9%) found in New York, Texas, Florida, Illinois, and New Jersey.

Though the prospect of screening so many newcomers and foreign-born residents may seem daunting, the report recommends two places to begin looking for active cases and the latently infected:

o immigrant screening that occurs stateside;

screening that occurs abroad.

Of the 800,000 people who undergo medical screening each year, a larger proportion is screened for TB prior to their departure by physicians appointed by U.S. consuls abroad. A smaller percentage is screened after arriving in the United States, usually because they have decided to apply for a change in immigration status.

In the overseas examinations given prior to immigration, immigrants and refugees with suspected TB are divided into these groups:

o Class A (sputum-positive, active TB cases, which must undergo treatment before departure);

o Class B1 and B2 (smear negative, but suspicious chest radiographs);

o Class B3 (calcified granulomas).

Though Class B immigrants are referred to health departments, the question of precisely how much follow-up gets done has gone unanswered until recently. The subject receives more attention now, Binkin says.

"People didn’t know how high the yield was for Class B1 and B2 immigrants, so we did a couple of studies," she says. The study results attracted notice: 3% to 14% of Class B1 immigrants and 0.4% to 14% of Class B2 immigrants were infected with active TB; half of B1s, plus a quarter of B2s, were candidates for isoniazid.

"We really tried to get the word out on that," says Binkin. The strategy worked. "Now, follow-up [of Class B1 and B2 immigrants] in many places is more than 90%. Upstate New York, an area with one of the lowest rates found at first look, now boasts follow-up in the 95% range.

Examinations performed here on the 200,000 residents annually seeking to adjust their residency status are conducted by civil surgeons, who again are expected to refer those who appear to be promising candidates for preventive therapy. Unlike with incoming immigrants, the referral process here still needs work, the report says. Health departments should provide those civil surgeons (who receive no particular TB training prior to their appointment by the Immigration and Naturalization Service) with the proper training and education to increase appropriate referrals, the working group concludes. (See related story on civil surgeons, p. 126.)

Contact tracing among the foreign-born poses special problems, the report states, especially in light of difficulties distinguishing recent infections from remote, and latent infections from bacille Calmette-Guerin (BCG) vaccination — or, perhaps, environmental mycobacteria. More studies are needed on yields that can be expected from such investigations, how completion-of-therapy rates stack up, and what incentives or enablers work to improve adherence.

Another issue identified in the report is the impact of rates of isoniazid resistance prevalent among some populations — 18.3% among Vietnamese, 14.7% among Filipinos, and 9.8% among Hispanics, compared with only 6.4% among U.S.-born patients. Given such rates, how effectively will a regimen of isoniazid prophylaxis hold up? What alternative might work better? Also on the working group’s wish list: an algorithm for interpreting a history of BCG vaccination.

The report gives the CDC plenty of homework:

o Round up more information on immigration trends, resistance rates, and treatment regimens in countries of origin.

o Start working on a national and bi-national tracking system.

o Address border issues.

o Establish lines of communication with foreign health care providers.

In the section on training, the report mentions several resources. For example, a cultural anthropologist’s perspective can be found at "Ethno Med,"a Web site established by the Harborview, WA, Refugee Clinic (www.hslib.washington.edu:443/clinical/ethnomed). In addition, compilations of material suitable for foreign-born audiences is available from a conference on training held earlier this month at the Francis J. Curry Model TB Center in San Francisco.