Estimating the impact of newly arrived foreign-born persons on tuberculosis in the United States

Tuberculosis Disease Among Nonimmigrant Visa Holders Reported to US Quarantine Stations, January 2011-June 2016

US-bound immigrants and refugees undergo a mandatory overseas medical examination that includes tuberculosis screening; this exam is not routinely required for temporary visitors applying for non-immigrant visas (NIV) to visit, work, or study in the United States. US health departments and foreign ministries of health report tuberculosis cases in travelers to Centers for Disease Control and Prevention Quarantine Stations. We reviewed cases reported to this passive surveillance system from January 2011 to June 2016. Of 1252 cases of tuberculosis in travelers reported to CDC, 114 occurred in travelers with a long-term NIV. Of these, 83 (73%) were infectious; 18 (16%) with multidrug-resistant tuberculosis (MDR TB) and one with extensively drug-resistant tuberculosis (XDR TB). We found evidence that NIV holders are diagnosed with tuberculosis disease in the United States. Given that long-term NIV holders were over-represented in this data set, despite the small proportion (4%) of overall non-immigrant admissions they represent, expanding the US overseas migration health screening program to this population might be an efficient intervention to further reduce tuberculosis in the United States.

Factors Associated with Development of Tuberculosis Disease Among Refugees, Massachusetts, 2008-2018

Refugees and immigrants undergo tuberculosis screening prior to arrival in the United States. CDC Technical Instructions for screening changed in 2007. Our goal was to quantify TB disease in refugees after 2007 and identify risks for disease. Massachusetts refugee and tuberculosis databases were matched to identify refugees who arrived 2008-2017 and were diagnosed with tuberculosis infection or disease 2008-2018. Factors associated with disease were analyzed in SAS. Of 19,583 refugees, 4706 were diagnosed with infection at arrival and 60 with disease during the observation period. Lack of treatment for infection was strongly associated (OR = 26.5, p = 0.0001) with diagnosis of disease; in a multivariate logistic regression model, positive screening test (AOR = 12.5, p = 0.0001), class B1 status (AOR = 4.0, p = 0.0004), and < 2 years since arrival (AOR = 60.0, p = 0.0001) were associated with disease. Providers should continue screening new arrivals, providing accessible services, and treating infection to further reduce tuberculosis morbidity and mortality.

Multidrug-Resistant Tuberculosis in U.S.-Bound Immigrants and Refugees

Rationale: Approximately two-thirds of new cases of tuberculosis (TB) in the United States are among non-U.S.-born persons. Culture-based overseas TB screening in U.S.-bound immigrants and refugees has substantially reduced the importation of TB into the United States, but it is unclear to what extent this program prevents the importation of multidrug-resistant TB (MDR-TB). Objectives: To study the epidemiology of MDR-TB in U.S.-bound immigrants and refugees and to evaluate the effect of culture-based overseas TB screening in U.S.-bound immigrants and refugees on reducing the importation of MDR-TB into the United States. Methods: We analyzed data of immigrants and refugees who completed overseas treatment for culture-positive TB during 2015-2019. We also compared mean annual number of MDR-TB cases in non-U.S.-born persons within 1 year of arrival in the United States between 1996-2006 (when overseas screening followed a smear-based algorithm) and 2014-2019 (after full implementation of a culture-based algorithm). Results: Of 3,300 culture-positive TB cases identified by culture-based overseas TB screening in immigrants and refugees during 2015-2019, 122 (3.7%; 95% confidence interval [CI], 3.1-4.1) had MDR-TB, 20 (0.6%; 95% CI, 0.3-0.9) had rifampicin-resistant TB, 382 (11.6%; 95% CI, 10.5-12.7) had isoniazid-resistant TB, and 2,776 (84.1%; 95% CI, 82.9-85.4) had rifampicin- and isoniazid-susceptible TB. None were diagnosed with extensively drug-resistant TB. All 3,300 persons with culture-positive TB completed treatment overseas; of 70 and 11 persons who were treated overseas for MDR-TB and rifampicin-resistant TB, respectively, none were diagnosed with TB disease at postarrival evaluation in the United States. Culture-based overseas TB screening in U.S.-bound immigrants and refugees prevented 24.4 MDR-TB cases per year from arriving in the United States, 18.2 cases more than smear-based overseas TB screening. The mean annual number of MDR-TB cases among non-U.S.-born persons within 1 year of arrival in the United States decreased from 34.6 cases in 1996-2006 to 19.5 cases in 2014-2019 (difference of 15.1; P < 0.001). Conclusions: Culture-based overseas TB screening in U.S.-bound immigrants and refugees substantially reduced the importation of MDR-TB into the United States.

Rifampin-resistant/multidrug-resistant Tuberculosis in Alberta, Canada: Epidemiology and treatment outcomes in a low-incidence setting

Treatment of rifampin-monoresistant/multidrug-resistant Tuberculosis (RR/MDR-TB) requires long treatment courses, complicated by frequent adverse events and low success rates. Incidence of RR/MDR-TB in Canada is low and treatment practices are variable due to the infrequent experience and challenges with drug access. We undertook a retrospective cohort study of all RR/MDR-TB cases in Alberta, Canada from 2007-2017 to explore the epidemiology and outcomes in our low incidence setting. We performed a descriptive analysis of the epidemiology, treatment regimens and associated outcomes, calculating differences in continuous and discrete variables using Student's t and Chi-squared tests, respectively. We identified 24 patients with RR/MDR-TB. All patients were foreign-born with the median time to presentation after immigration being 3 years. Prior treatment was reported in 46%. Treatment was individualized. All patients achieved sputum culture conversion within two months of treatment initiation. The median treatment duration after culture conversion was 18 months (IQR: 15-19). The mean number of drugs utilized during the intensive phase was 4.3 (SD: 0.8) and during the continuation phase was 3.3 (SD: 0.9) and the mean adherence to medications was 95%. Six patients completed national guideline-concordant therapy, with many patients developing adverse events (79%). Treatment success (defined as completion of prescribed therapy or cure) was achieved in 23/24 patients and no acquired drug resistance or relapse was detected over 1.8 years of median follow-up. Many cases were captured upon immigration assessment, representing important prevention of community spread. Despite high rates of adverse events and short treatment compared to international guidelines, success in our cohort was very high at 96%. This is likely due to individualization of therapy, frequent use of medications with high effectiveness, intensive treatment support, and early sputum conversion seen in our cohort. There should be ongoing exploration of treatment shortening with well-tolerated, efficacious oral agents to help patients achieve treatment completion.

Cost effectiveness analysis of implementing tuberculosis screening among applicants for non-immigrant U.S. work visas

Background

While persons who receive immigrant and refugee visas are screened for active tuberculosis before admission into the United States, nonimmigrant visa applicants (NIVs) are not routinely screened and may enter the United States with infectious tuberculosis.

Objectives

We evaluated the costs and benefits of expanding pre-departure tuberculosis screening requirements to a subset of NIVs who arrive from a moderate (Mexico) or high (India) incidence tuberculosis country with temporary work visas.

Methods

We developed a decision tree model to evaluate the program costs and estimate the numbers of active tuberculosis cases that may be diagnosed in the United States in two scenarios: 1) “Screening”: screening and treatment for tuberculosis among NIVs in their home country with recommended U.S. follow-up for NIVs at elevated risk of active tuberculosis; and, 2) “No Screening” in their home country so that cases would be diagnosed passively and treatment occurs after entry into the United States. Costs were assessed from multiple perspectives, including multinational and U.S.-only perspectives.

Results

Under “Screening” versus “No Screening”, an estimated 179 active tuberculosis cases and 119 hospitalizations would be averted in the United States annually via predeparture treatment. From the U.S.-only perspective, this program would result in annual net cost savings of about $3.75 million. However, rom the multinational perspective, the screening program would cost $151,388 per U.S. case averted for Indian NIVs and $221,088 per U.S. case averted for Mexican NIVs.

Conclusion

From the U.S.-only perspective, the screening program would result in substantial cost savings in the form of reduced treatment and hospitalization costs. NIVs would incur increased pre-departure screening and treatment costs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41479-020-00078-z.

Impact of Effective Global Tuberculosis Control on Health and Economic Outcomes in the United States

Rationale: Most U.S. residents who develop tuberculosis (TB) were born abroad, and U.S. TB incidence is increasingly driven by infection risks in other countries.

Objectives: To estimate the potential impact of effective global TB control on health and economic outcomes in the United States.

Methods: We estimated outcomes using linked mathematical models of TB epidemiology in the United States and migrants’ birth countries. A base-case scenario extrapolated country-specific TB incidence trends. We compared this with scenarios in which countries achieve 90% TB incidence reductions between 2015 and 2035, as targeted by the World Health Organization’s End TB Strategy (“effective global TB control”). We also considered pessimistic scenarios of flat TB incidence trends in individual countries.

Measurements and Main Results: We estimated TB cases, deaths, and costs and the total economic burden of TB in the United States. Compared with the base-case scenario, effective global TB control would avert 40,000 (95% uncertainty interval, 29,000–55,000) TB cases in the United States in 2020–2035. TB incidence rates in 2035 would be 43% (95% uncertainty interval, 34–54%) lower than in the base-case scenario, and 49% (95% uncertainty interval, 44–55%) lower than in 2020. Summed over 2020–2035, this represents 0.8 billion dollars (95% uncertainty interval, 0.6–1.0 billion dollars) in averted healthcare costs and $2.5 billion dollars (95% uncertainty interval, 1.7–3.6 billion dollars) in productivity gains. The total U.S. economic burden of TB (including the value of averted TB deaths) would be 21% (95% uncertainty interval, 16–28%) lower (18 billion dollars [95% uncertainty level, 8–32 billion dollars]).

Conclusions: In addition to producing major health benefits for high-burden countries, strengthened efforts to achieve effective global TB control could produce substantial health and economic benefits for the United States.

Assessing Complexity Among Patients With Tuberculosis in California, 1993-2016

Background

Although the number of patients with active tuberculosis (TB) has decreased in the last 25 years, anecdotal reports suggest that the complexity of these patients has increased. However, this complexity and its components have never been quantified or defined. We therefore aimed to describe the complexity of patients with active TB in California during 1993–2016.

Methods

We analyzed data on patient comorbidities, clinical features, and demographics from the California Department of Public Health TB Registry. All adult patients who were alive at the time of TB diagnosis in California during 1993–2016 were included in the analyses. Factors deemed by an expert panel to increase complexity (ie, increased resources or expertise requirement for successful management) were analyzed and included the following: age >75 years, HIV infection, multidrug resistance (MDR), and extrapulmonary TB disease. Second, using additional information on other comorbidities available starting in 2010, we performed exploratory factor analysis on 25 variables in order to define the dimensions of complexity.

Results

Among the 67512 patients analyzed, the proportion of patients with extrapulmonary disease, age >75 years, or MDR-TB each increased over the study period (P < .001), while the proportion of patients with HIV decreased. Furthermore, the proportion of patients with at least 1 factor of those increased, rising from 38.8% to 45.3% (P < .001) from 1993 to 2016. Dimensions of complexity identified in the exploratory factor analysis included the following: race/immigration, social features, elderly/institutionalized, advanced TB, comorbidity, and drug resistance risk.

Conclusions

In this first description of complexity in the setting of TB, we found that the complexity of patients with active TB has risen over the last 25 years in California. These findings suggest that despite the overall decline in active TB cases, effective management of more complex patients may require additional attention and resource investment.

The impact of migration on tuberculosis in the United States

Due to greater exposure to Mycobacterium tuberculosis infection before migration, migrants moving to low-incidence settings can experience substantially higher tuberculosis (TB) rates than the native-born population. This review describes the impact of migration on TB epidemiology in the United States, and how the TB burden differs between US-born and non-US-born populations. The United States has a long history of receiving migrants from other parts of the world, and TB among non-US-born individuals now represents the majority of new TB cases. Based on an analysis of TB cases among individuals from the top 30 countries of origin in terms of non-US-born TB burden between 2003 and 2015, we describe how TB risks vary within the non-US-born population according to age, years since entry, entry year, and country of origin. Variation along each of these dimensions is associated with more than 10-fold differences in the risk of developing active TB, and this risk is also positively associated with TB incidence estimates for the country of origin and the composition of the migrant pool in the entry year. Approximately 87 000 lifetime TB cases are predicted for the non-US-born population resident in the United States in 2015, and 5800 lifetime cases for the population entering the United States in 2015.

Pre-immigration Screening for Tuberculosis in South Korea: A Comparison of Smear- and Culture-Based Protocols

BACKGROUND

Tuberculosis (TB) is the most important disease screened for upon patient history review during preimmigration medical examinations as performed in South Korea in prospective immigrants to certain Western countries. In 2007, the U.S. Centers for Disease Control and Prevention (CDC) changed the TB screening protocol from a smear-based test to the complete Culture and Directly Observed Therapy Tuberculosis Technical Instructions (CDOT TB TI) for reducing the incidence of TB in foreign-born immigrants.

METHODS

This study evaluated the effect of the revised (as compared with the old) protocol in South Korea.

RESULTS

Of the 40,558 visa applicants, 365 exhibited chest radiographic results suggestive of active or inactive TB, and 351 underwent sputum tests (acid-fast bacilli smear and Mycobacterium tuberculosis culture). To this end, using the CDOT TB TI, 36 subjects (88.8 per 10⁵ of the population) were found to have TB, compared with only seven using the older U.S. CDC technical instruction (TI) (p<0.001). In addition, there were six drug-resistant cases which were identified (16.7 per 10⁵ of the population), two of whom had multidrug-resistance (5.6 per 10⁵ of the population).

CONCLUSION

The culture-based 2007 TI identified a great deal of TB cases current to the individuals tested, as compared to older U.S. CDC TI.

Yield of testing and treatment for tuberculosis among foreign-born persons during contact investigations in the United States: A semi-systematic review

BACKGROUND

Contact investigation is an important strategy for maintaining control of tuberculosis (TB) in the United States. However, testing and treatment outcomes specifically to foreign-born populations are poorly understood. We reviewed literature on testing and LTBI identified during contact investigations in foreign-born populations living in the US.

METHODS

We conducted a comprehensive search of peer-reviewed and grey literature using Cochrane systematic review methods. We included studies with adult and adolescent populations that were at least 50% foreign-born. Pooled proportions and 95% confidence intervals (CIs) were calculated via inverse-variance weighted meta-analysis, and cumulative proportions were calculated as products of adjacent step proportions.

RESULTS

We identified 22 studies published between 1997 and 2014 that included at least 50% foreign-born participants. From studies of predominantly (>90%) foreign-born populations, almost all identified contacts were recruited and had valid test results, and 54.8% (95% CI 45.1-62.5%) of contacts with valid test results tested positive. From studies of majority (50% to 90%) foreign-born populations, 78.4% (95% CI 78.0-78.9%) of identified contacts were recruited, 92.0% (95% CI 91.6-92.3%) of recruited contacts had valid test results, and 38.5% (95% CI 31.9%-44.2%) of persons with valid results tested positive. These proportions varied by test type in studies of predominantly foreign-born populations. For every 1000 contacts identified in predominantly foreign-born populations, we estimate that 535 (95% CI 438 to 625) will test positive, and 354 (95% CI 244 to 453) will complete LTBI treatment. For every 1000 contacts identified in majority foreign-born populations, these estimates are 276 (95% CI 230 to 318), and 134 (95% CI 44 to 264), respectively.

CONCLUSIONS

Contact investigation is a high yield activity for identifying and treating foreign-born persons with LTBI, but must be complemented by other tuberculosis control activities in order to achieve continued progress toward TB elimination.

The Potential Impact of Border Security Upon Prevalence of Infectious Disease

In the U.S., migration has been documented to affect the prevalence of infectious disease. As a mitigation entity, border security has been recorded by numerous scholarly works as being essential to the support of the health of the U.S. population. Consequently, the lack of current health care monitoring of the permeable U.S. border places the U.S. population at risk in the broad sectors of infectious disease and interpersonal violence. Visualizing border security in the context of public health mitigation has significant potential to protect migrant health as well as that of all populations on both sides of the border. Examples of how commonly this philosophy is held can be found in the expansive use of security-focused terms regarding public health. Using tools such as GIS to screen for disease in people before their entrance into a nation would be more efficient and ethical than treating patients once they have entered a population and increased the impact on the healthcare system. (Disaster Med Public Health Preparedness. 2018;12:554-562).

Prevalence of Chronic Disease and Their Risk Factors Among Iranian, Ukrainian, Vietnamese Refugees in California, 2002-2011

Little is known about how the health status of incoming refugees to the United States compares to that of the general population. We used logistic regression to assess whether country of origin is associated with prevalence of hypertension, obesity, type-II diabetes, and tobacco-use among Iranian, Ukrainian and Vietnamese refugees arriving in California from 2002 to 2011 (N = 21,968). We then compared the prevalence among refugees to that of the Californian general population (CGP). Ukrainian origin was positively associated with obesity and negatively with smoking, while the opposite was true for Vietnamese (p < 0.001). Iranian origin was positively associated with type-II diabetes and smoking (p < 0.001). After accounting for age and gender differences, refugees had lower prevalence of obesity and higher prevalence of smoking than CGP. Individually, all refugee groups had lower type-II diabetes prevalence than CGP. Grouping all refugees together can hide distinct health needs associated with country of origin.

Toward a generation free of tuberculosis: TB disease and infection in individuals of college age in the United States

OBJECTIVES

To assess the magnitude of active TB disease and latent TB infection (LTBI) in young adults of college age.

PARTICIPANTS

Individuals who were aged 18-24 years in 2011 were used as a proxy for college students.

METHODS

Active TB cases reported to the 2011 US National TB Surveillance System (NTSS) were included. LTBI prevalence was calculated from the 2011-2012 National Health and Nutrition Examination Survey. The 2011 American Community Survey was used to calculate population denominators. Analyses were stratified by nativity.

RESULTS

Active TB disease incidence among persons aged 18-24 years was 2.82/100,000, 18.8/100,000 among foreign-born individuals and 0.9/100,000 among US-born individuals. In 2011, 878 TB cases were reported; 629 (71.6%) were foreign-born. LTBI prevalence among persons of 18-24 years was 2.5%: 8.7% and 1.3% among foreign-born and US-born, respectively.

CONCLUSION

Active screening and treatment programs for foreign-born young adults could identify TB cases earlier and provide an opportunity for prevention efforts.

Tuberculosis in Enclosed Populations

Transmission of tuberculosis (TB) is most effective in close contact indoor environments in various congregate settings including health care facilities, homeless shelters, correctional facilities, long-term care facilities, as well as community settings such as homes, schools, workplaces, and various modes of transportation. Outbreaks are fueled by numerous factors including the HIV epidemic, ease of global travel, unstable socio-economic and/or political situations, and lapses in response to potentially infectious patients. Organized approaches to TB control include an appropriate index of suspicion, identification and isolation of contagious patients in appropriate facilities, use of environmental controls, and personal protective equipment in accordance to national and international published guidelines. These all require tailoring to the various settings where TB is encountered using a determination of risk. Concerted efforts at the local, regional, national, and international levels at identifying patients with active disease, enforcing completion of treatment, and testing and fully treating patients with latent TB infection are paramount in reducing TB burden and continued transmission.

High Rates of Tuberculosis and Opportunities for Prevention among International Students in the United States

RATIONALE

Foreign-born persons traveling on a student visa are not currently screened for tuberculosis on entry into the United States, despite residing in the United States for up to several years.

OBJECTIVES

To characterize the risk of tuberculosis in international students entering the United States and to identify strategies for early diagnosis and prevention in this population.

METHODS

Data were collected in 18 tuberculosis control jurisdictions in the United States. A cohort of 1,268 foreign-born patients of known visa status, diagnosed with active tuberculosis between 2004 and 2007, was used for analysis. Incidence rates were estimated on the basis of immigration data from study jurisdictions.

MEASUREMENTS AND MAIN RESULTS

Tuberculosis was diagnosed in 46 student residents, providing an annual estimate of 308 cases nationally. The estimated tuberculosis case rate in student residents was 48.1 cases per 100,000 person-years (95% confidence interval, 35.6-64.8), more than twice that of the general foreign-born population. Students identified by tuberculosis screening programs were more likely to be diagnosed within 6 months of U.S. arrival (75 vs. 6%; P < 0.001), and those with pulmonary disease were less likely to have a positive sputum smear for acid-fast bacilli compared with those not screened (18 vs. 63%; P = 0.05). In unscreened students, 71% were diagnosed more than 1 year after U.S. arrival and only 6% were previously treated for latent tuberculosis infection.

CONCLUSIONS

The tuberculosis case rate in foreign-born students is significantly higher than in other foreign-born individuals. Screening this group after arrival to the United States is an effective strategy for earlier diagnosis of active tuberculosis.

Crossborder travel and multidrugresistant tuberculosis (MDRTB) in Europe

The number of international migrants worldwide has continued to grow rapidly over the past fifteen years and the trend is expected to continue, making the health matters associated with migration a crucial public health challenges faced by governments and societies. Multidrug-resistant tuberculosis is a paradigm of transmissible diseases that do not respect borders and poses a multifaceted and complex challenge on migrant health. The guiding principles for the health response are the respect of equity and human rights as well as the accurate analysis of epidemiological trends and determinants of TB in migrants. The action framework "Towards tuberculosis elimination: an action framework for low-incidence countries" includes regulations for cross border migration among the top eight interventions for TB elimination in low incidence countries. Political commitment is the essential requirement, and currently, the limiting factor, to draft regulations for cross-border collaboration, establish cross-border referral systems with contact tracing and information sharing. The e-platform TB Consilium hosted by European Respiratory Society in collaboration with World Health Organization - Euro is an example of a tool that can be used to exchange information for clinical management and surveillance.

Use of Transnational Services to Prevent Treatment Interruption in Tuberculosis-Infected Persons Who Leave the United States

Scale up of such services is possible and encouraged because of potential health gains and reduced healthcare costs.

A major problem resulting from interrupted tuberculosis (TB) treatment is the development of drug-resistant TB, including multidrug-resistant TB (MDR TB), a more deadly and costly-to-treat form of the disease. Global health systems are not equipped to diagnose and treat the current burden of MDR TB. TB-infected foreign visitors and temporary US residents who leave the country during treatment can experience treatment interruption and, thus, are at greater risk for drug-resistant TB. Using epidemiologic and demographic data, we estimated TB incidence among this group, as well as the proportion of patients referred to transnational care–continuity and management services during relocation; each year, ≈2,827 visitors and temporary residents are at risk for TB treatment interruption, 222 (8%) of whom are referred for transnational services. Scale up of transnational services for persons at high risk for treatment interruption is possible and encouraged because of potential health gains and reductions in healthcare costs for the United States and receiving countries.

US college and university student health screening requirements for tuberculosis and vaccine-preventable diseases, 2012

OBJECTIVE

Colleges are at risk for communicable disease outbreaks because of the high degree of person-to-person interactions and relatively crowded dormitory settings. This report describes the US college student health screening requirements among US resident and international students for tuberculosis (TB) and vaccine-preventable diseases (VPDs) as they relate to the American College Health Association (ACHA) guidelines. Methods/Participants: In April 2012, US college health administrators (N = 2,858) were sent online surveys to assess their respective school's TB screening and immunization requirements.

RESULTS

Surveys were completed by 308 (11%) schools. Most schools were aware of the ACHA immunization (78%) and TB screening (76%) guidelines. Schools reported having policies related to immunization screening (80.4%), immunization compliance (93%), TB screening (55%), and TB compliance (87%).

CONCLUSION

Most colleges were following ACHA guidelines. However, there are opportunities for improvement to fully utilize the recommendations and prevent outbreaks of communicable diseases among students in colleges.

Active Tuberculosis Case Finding Interventions Among Immigrants, Refugees and Asylum Seekers in Italy

In Italy tuberculosis (TB) is largely concentrated in vulnerable groups such as migrants and in urban settings. We analyzed three TB case finding interventions conducted at primary centers and mobile clinics for regular/irregular immigrants and refugees/asylum seekers performed over a four-year period (November 2009-March 2014) at five different sites in Rome and one site in Milan, Italy. TB history and presence of symptoms suggestive of active TB were investigated by verbal screening through a structured questionnaire in migrants presenting for any medical condition to out-patient and mobile clinics. Individuals reporting TB history or symptoms were referred to a TB clinic for diagnostic workup. Among 6347 migrants enrolled, 891 (14.0%) reported TB history or symptoms suggestive of active TB and 546 (61.3%) were referred to the TB clinic. Of them, 254 (46.5%) did not present for diagnostic evaluation. TB was diagnosed in 11 individuals representing 0.17% of those screened and 3.76% of those evaluated. The overall yield of this intervention was in the range reported for other TB screening programs for migrants, although we recorded an unsatisfactory adherence to diagnostic workup. Possible advantages of this intervention include low cost and reduced burden of medical procedures for the screened population.

Getting to Zero: Tuberculosis Elimination in California

This review of tuberculosis epidemiology is intended to provide a historical perspective on the public health approach to tuberculosis (TB) control in California. This historical context offers a lens through which to view current epidemiologic trends and insight into how new therapeutic tools can be applied. Since 1993, the year detailed case reporting was instituted, California has had a decrease in recent TB transmission as evidenced by a reduction in pediatric cases and an increased percentage of cases attributable to progression of latent infection to TB disease in the foreign-born population. Overall, there has been a dramatic decline in the annual TB case count, but the speed of the decline has slowed over the last several years. At the current pace and case count of 2137 in 2015, California will not achieve TB elimination (<1 TB case per one million population) for at least 100 years. There are an estimated 2.1 million persons in California with latent TB infection. Modeling suggests that LTBI detection and treatment are important in reaching TB elimination. For this reason, a coalition of stakeholders in California is exploring novel approaches to accelerate the case decline in order to prevent unnecessary disease and death.

Abrupt Decline in Tuberculosis among Foreign-Born Persons in the United States

While the number of reported tuberculosis (TB) cases in the United States has declined over the past two decades, TB morbidity among foreign-born persons has remained persistently elevated. A recent unexpected decline in reported TB cases among foreign-born persons beginning in 2007 provided an opportunity to examine contributing factors and inform future TB control strategies. We investigated the relative influence of three factors on the decline: 1) changes in the size of the foreign-born population through immigration and emigration, 2) changes in distribution of country of origin among foreign-born persons, and 3) changes in the TB case rates among foreign-born subpopulations. Using data from the U.S. National Tuberculosis Surveillance System and the American Community Survey, we examined TB case counts, TB case rates, and population estimates, stratified by years since U.S. entry and country of origin. Regression modeling was used to assess statistically significant changes in trend. Among foreign-born recent entrants (<3 years since U.S. entry), we found a 39.5% decline (-1,013 cases) beginning in 2007 (P<0.05 compared to 2000–2007) and ending in 2011 (P<0.05 compared to 2011–2014). Among recent entrants from Mexico, 80.7% of the decline was attributable to a decrease in population, while the declines among recent entrants from the Philippines, India, Vietnam, and China were almost exclusively (95.5%–100%) the result of decreases in TB case rates. Among foreign-born non-recent entrants (≥3 years since U.S. entry), we found an 8.9% decline (-443 cases) that resulted entirely (100%) from a decrease in the TB case rate. Both recent and non-recent entrants contributed to the decline in TB cases; factors contributing to the decline among recent entrants varied by country of origin. Strategies that impact both recent and non-recent entrants (e.g., investment in overseas TB control) as well as those that focus on non-recent entrants (e.g., expanded targeted testing of high-risk subgroups among non-recent entrants) will be necessary to achieve further declines in TB morbidity among foreign-born persons.

Transnational Record Linkage for Tuberculosis Surveillance and Program Evaluation

OBJECTIVE

Pre-immigration tuberculosis (TB) screening, followed by post-arrival rescreening during the first year, is critical to reducing TB among foreign-born people in the United States. However, existing U.S. public health surveillance is inadequate to monitor TB among immigrants during subsequent years. We developed and tested a novel method for ascertaining post-U.S.-arrival TB outcomes among high-TB-risk immigrant cohorts to improve surveillance.

METHODS

We used a probabilistic record linkage program to link pre-immigration screening records from U.S.-bound immigrants from the Philippines (n=422,593) and Vietnam (n=214,401) with the California TB registry during 2000-2010. We estimated sensitivity using Monte Carlo simulations to account for uncertainty in key inputs. Specificity was evaluated by using a time-stratified approach, which defined false-positives as TB records linked to pre-immigration screening records dated after the person had arrived in the United States.

RESULTS

TB was reported in 4,382 and 2,830 people born in the Philippines and Vietnam, respectively, in California during the study period. Of these TB cases, records for 973 and 452 cases of people born in the Philippines and Vietnam, respectively, were linked to pre-immigration screening records. Sensitivity and specificity of linkage were 89% (90% credible interval [CrI] 83, 97) and 100%, respectively, for the Philippines, and 90% (90% CrI 83, 98) and 99.9%, respectively, for Vietnam.

CONCLUSION

Electronic linkage of pre-immigration screening records to a domestic TB registry was feasible, sensitive, and highly specific in two high-priority immigrant cohorts. Transnational record linkage can be used for program evaluation and routine monitoring of post-U.S.-arrival TB risk among immigrants, but requires interagency data sharing and collaboration.

A cost-benefit analysis of a proposed overseas refugee latent tuberculosis infection screening and treatment program

BACKGROUND

This study explored the effect of screening and treatment of refugees for latent tuberculosis infection (LTBI) before entrance to the United States as a strategy for reducing active tuberculosis (TB). The purpose of this study was to estimate the costs and benefits of LTBI screening and treatment in United States bound refugees prior to arrival.

METHODS

Costs were included for foreign and domestic LTBI screening and treatment and the domestic treatment of active TB. A decision tree with multiple Markov nodes was developed to determine the total costs and number of active TB cases that occurred in refugee populations that tested 55, 35, and 20 % tuberculin skin test positive under two models: no overseas LTBI screening and overseas LTBI screening and treatment. For this analysis, refugees that tested 55, 35, and 20 % tuberculin skin test positive were divided into high, moderate, and low LTBI prevalence categories to denote their prevalence of LTBI relative to other refugee populations.

RESULTS

For a hypothetical 1-year cohort of 100,000 refugees arriving in the United States from regions with high, moderate, and low LTBI prevalence, implementation of overseas screening would be expected to prevent 440, 220, and 57 active TB cases in the United States during the first 20 years after arrival. The cost savings associated with treatment of these averted cases would offset the cost of LTBI screening and treatment for refugees from countries with high (net cost-saving: $4.9 million) and moderate (net cost-saving: $1.6 million) LTBI prevalence. For low LTBI prevalence populations, LTBI screening and treatment exceed expected future TB treatment cost savings (net cost of $780,000).

CONCLUSIONS

Implementing LTBI screening and treatment for United States bound refugees from countries with high or moderate LTBI prevalence would potentially save millions of dollars and contribute to United States TB elimination goals. These estimates are conservative since secondary transmission from tuberculosis cases in the United States was not considered in the model.

Preventing Infectious Pulmonary Tuberculosis Among Foreign-Born Residents of the United States

OBJECTIVES

We described risk factors associated with infectious tuberculosis (TB) and missed TB-prevention opportunities in foreign-born US residents, who account for almost two thirds of the nation's TB patients.

METHODS

In a cross-sectional study at 20 US sites of foreign-born persons diagnosed with TB in 2005 through 2006, we collected results of sputum smear microscopy for acid-fast bacilli (a marker for infectiousness) and data on visa status, sociodemographics, TB-related care seeking, and latent TB infection (LTBI) diagnosis opportunities.

RESULTS

Among 980 persons with pulmonary TB who reported their visa status, 601 (61%) were legal permanent residents, 131 (13.4%) had temporary visas, and 248 (25.3%) were undocumented. Undocumented persons were more likely than permanent residents to have acid-fast bacilli-positive smears at diagnosis (risk ratio = 1.3; 95% confidence interval = 1.2, 1.4). Of those diagnosed 1 year or more after arrival, 57.3% reported LTBI screening opportunities; fewer than 25% actually were. Undocumented persons reported fewer LTBI screening opportunities and were less likely to be tested.

CONCLUSIONS

Progress toward TB elimination in the United States depends upon expanding opportunities for regular medical care and promotion of LTBI screening and treatment among foreign-born persons.

Cost-Effectiveness of Screening and Treating Foreign-Born Students for Tuberculosis before Entering the United States

Introduction

The Centers for Disease Control and Prevention is considering implementation of overseas medical screening of student-visa applicants to reduce the numbers of active tuberculosis cases entering the United States.

Objective

To evaluate the costs, cases averted, and cost-effectiveness of screening for, and treating, tuberculosis in United States-bound students from countries with varying tuberculosis prevalence.

Methods

Costs and benefits were evaluated from two perspectives, combined and United States only. The combined perspective totaled overseas and United States costs and benefits from a societal perspective. The United States only perspective was a domestic measure of costs and benefits. A decision tree was developed to determine the cost-effectiveness of tuberculosis screening and treatment from the combined perspective.

Results

From the United States only perspective, overseas screening programs of Chinese and Indian students would prevent the importation of 157 tuberculosis cases annually, and result in $2.7 million in savings. From the combined perspective, screening programs for Chinese students would cost more than $2.8 million annually and screening programs for Indian students nearly $440,000 annually. From the combined perspective, the incremental cost for each tuberculosis case averted by screening Chinese and Indian students was $22,187 and $15,063, respectively. Implementing screening programs for German students would prevent no cases in most years, and would result in increased costs both overseas and in the United States. The domestic costs would occur because public health departments would need to follow up on students identified overseas as having an elevated risk of tuberculosis.

Conclusions

Tuberculosis screening and treatment programs for students seeking long term visas to attend United States schools would reduce the number of tuberculosis cases imported. Implementing screening in high-incidence countries could save the United States millions of dollars annually; however there would be increased costs incurred overseas for students and their families.

Towards tuberculosis elimination: an action framework for low-incidence countries

This paper describes an action framework for countries with low tuberculosis (TB) incidence (<100 TB cases per million population) that are striving for TB elimination. The framework sets out priority interventions required for these countries to progress first towards "pre-elimination" (<10 cases per million) and eventually the elimination of TB as a public health problem (less than one case per million). TB epidemiology in most low-incidence countries is characterised by a low rate of transmission in the general population, occasional outbreaks, a majority of TB cases generated from progression of latent TB infection (LTBI) rather than local transmission, concentration to certain vulnerable and hard-to-reach risk groups, and challenges posed by cross-border migration. Common health system challenges are that political commitment, funding, clinical expertise and general awareness of TB diminishes as TB incidence falls. The framework presents a tailored response to these challenges, grouped into eight priority action areas: 1) ensure political commitment, funding and stewardship for planning and essential services; 2) address the most vulnerable and hard-to-reach groups; 3) address special needs of migrants and cross-border issues; 4) undertake screening for active TB and LTBI in TB contacts and selected high-risk groups, and provide appropriate treatment; 5) optimise the prevention and care of drug-resistant TB; 6) ensure continued surveillance, programme monitoring and evaluation and case-based data management; 7) invest in research and new tools; and 8) support global TB prevention, care and control. The overall approach needs to be multisectorial, focusing on equitable access to high-quality diagnosis and care, and on addressing the social determinants of TB. Because of increasing globalisation and population mobility, the response needs to have both national and global dimensions.

Effect of a culture-based screening algorithm on tuberculosis incidence in immigrants and refugees bound for the United States: a population-based cross-sectional study

BACKGROUND

Before 2007, immigrants and refugees bound for the United States were screened for tuberculosis (TB) by a smear-based algorithm that could not diagnose smear-negative/culture-positive TB. In 2007, the Centers for Disease Control and Prevention implemented a culture-based algorithm.

OBJECTIVE

To evaluate the effect of the culture-based algorithm on preventing the importation of TB to the United States by immigrants and refugees from foreign countries.

DESIGN

Population-based, cross-sectional study.

SETTING

Panel physician sites for overseas medical examination.

PATIENTS

Immigrants and refugees with TB.

MEASUREMENTS

Comparison of the increase of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees by the culture-based algorithm with the decline of reported cases among foreign-born persons within 1 year after arrival in the United States from 2007 to 2012.

RESULTS

Of the 3 212 421 arrivals of immigrants and refugees from 2007 to 2012, a total of 1 650 961 (51.4%) were screened by the smear-based algorithm and 1 561 460 (48.6%) were screened by the culture-based algorithm. Among the 4032 TB cases diagnosed by the culture-based algorithm, 2195 (54.4%) were smear-negative/culture-positive. Before implementation (2002 to 2006), the annual number of reported cases among foreign-born persons within 1 year after arrival was relatively constant (range, 1424 to 1626 cases; mean, 1504 cases) but decreased from 1511 to 940 cases during implementation (2007 to 2012). During the same period, the annual number of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees bound for the United States by the culture-based algorithm increased from 4 to 629.

LIMITATION

This analysis did not control for the decline in new arrivals of nonimmigrant visitors to the United States and the decrease of incidence of TB in their countries of origin.

CONCLUSION

Implementation of the culture-based algorithm may have substantially reduced the incidence of TB among newly arrived, foreign-born persons in the United States.

PRIMARY FUNDING SOURCE

None.

USA's expanded overseas tuberculosis screening program: a retrospective study in China

BACKGROUND

To address increasing tuberculosis (TB) incidence in foreign-born populations, immigrant TB screening programs have been implemented in the USA. These programs are modified periodically, the effectiveness of which have been disputed. The aim of this retrospective study was to assess the value of the 2009 Technical Instructions for Tuberculosis Screening and Treatment Using Cultures and Directly Observed Therapy (CDOT TB TI) in a cohort of the USA permanent-resident applicants from China.

METHODS

Standardized forms were used to collect demographic, clinical, and laboratory data of Chinese individuals screened at the Guangdong International Travel Healthcare Center for permanent residence in the USA between October 08, 2009 and December 31, 2012. Applicants' data were further retrospectively evaluated by three experienced panel physicians and radiologists according to the 1991 Technical Instructions for Tuberculosis Screening and Treatment (TI). TB cases and characteristics identified by the 1991 and expanded 2009 programs were compared.

RESULTS

The CDOT TB TI identified more than twice as many TB cases that required treatment completion before clearance for travel than the 1991 TI (270 vs. 131). In addition, the expanded screening program identified more cases of negative sputum smear but positive culture (181 vs. 44), and more cases of radiography suggestive of inactive (22 vs. 3) and active (248 vs. 128) TB. Specifically, the 1991 TI screening program failed to identify 25/38 (65.79%) cases carrying drug-resistant isolates, and 13/131 (9.92%) would have been inappropriately treated. Moreover, 220/270 (81.48%) of the cases were asymptomatic, which were identified by screening and subsequently treated. Improved chest radiograph and sputum negative conversion occurred in all treated cases.

CONCLUSION

CDOT TB TI, a screening program that includes sputum culture and drug susceptibility tests, identifies a greater number of TB cases, likely contributing to the overall decrease in TB prevalence in host (USA) and origin (China) countries.

Unraveling Mycobacterium tuberculosis genomic diversity and evolution in Lisbon, Portugal, a highly drug resistant setting

Background

Multidrug- (MDR) and extensively drug resistant (XDR) tuberculosis (TB) presents a challenge to disease control and elimination goals. In Lisbon, Portugal, specific and successful XDR-TB strains have been found in circulation for almost two decades.

Results

In the present study we have genotyped and sequenced the genomes of 56 Mycobacterium tuberculosis isolates recovered mostly from Lisbon. The genotyping data revealed three major clusters associated with MDR-TB, two of which are associated with XDR-TB. Whilst the genomic data contributed to elucidate the phylogenetic positioning of circulating MDR-TB strains, showing a high predominance of a single SNP cluster group 5. Furthermore, a genome-wide phylogeny analysis from these strains, together with 19 publicly available genomes of Mycobacterium tuberculosis clinical isolates, revealed two major clades responsible for M/XDR-TB in the region: Lisboa3 and Q1 (LAM).

The data presented by this study yielded insights on microevolution and identification of novel compensatory mutations associated with rifampicin resistance in rpoB and rpoC. The screening for other structural variations revealed putative clade-defining variants. One deletion in PPE41, found among Lisboa3 isolates, is proposed to contribute to immune evasion and as a selective advantage. Insertion sequence (IS) mapping has also demonstrated the role of IS6110 as a major driver in mycobacterial evolution by affecting gene integrity and regulation.

Conclusions

Globally, this study contributes with novel genome-wide phylogenetic data and has led to the identification of new genomic variants that support the notion of a growing genomic diversity facing both setting and host adaptation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-991) contains supplementary material, which is available to authorized users.

Attitudes about tuberculosis prevention in the elimination phase: a survey among physicians in Germany

Background

Targeted and stringent measures of tuberculosis prevention are necessary to achieve the goal of tuberculosis elimination in countries of low tuberculosis incidence.

Methods

We ascertained the knowledge about tuberculosis risk factors and stringency of tuberculosis prevention measures by a standardized questionnaire among physicians in Germany involved in the care of individuals from classical risk groups for tuberculosis.

Results

510 physicians responded to the online survey. Among 16 risk factors immunosuppressive therapy, HIV-infection and treatment with TNF-antagonist were thought to be the most important risk factors for the development of tuberculosis in Germany. Exposure to a patient with tuberculosis ranked on the 10^th position. In the event of a positive tuberculin-skin-test or interferon-γ release assay only 50%, 40%, 36% and 25% of physicians found that preventive chemotherapy was indicated for individuals undergoing tumor necrosis factor-antagonist therapy, close contacts of tuberculosis patients, HIV-infected individuals and migrants, respectively.

Conclusions

A remarkably low proportion of individuals with latent infection with Mycobacterium tuberculosis belonging to classical risk groups for tuberculosis are considered candidates for preventive chemotherapy in Germany. Better knowledge about the risk for tuberculosis in different groups and more stringent and targeted preventive interventions will probably be necessary to achieve tuberculosis elimination in Germany.

Diagnosis of latent tuberculosis infection with T-SPOT(®).TB in a predominantly immigrant population with rheumatologic disorders

PURPOSE

The objective of this study is to compare how likely positive tuberculin skin test (TST) and T-SPOT(®).TB (TSPOT) results predict risk factors for tuberculosis in a predominantly immigrant patient population at risk of latent TB infection (LTBI) and with rheumatologic conditions requiring immunomodulatory therapy (IMT).

METHODS

Prospective study conducted at a referral rheumatology clinic. Inclusion criteria included patients on various IMT, including immunosuppressive drugs that could predispose to TB progression. We studied risk factors associated with LTBI, test results, and tests' agreement.

RESULTS

We studied 101 patients. Eighty (79.2 %) were from countries where TB is prevalent and Bacille Calmette-Guérin vaccination is placed routinely. Seventy-four (73.3 %) had rheumatoid arthritis and 92 (90.7 %) were on IMT. Among patients with both TST and TSPOT results, 25 (30.9 %) were TST(+) and 20 (24.7 %) had TSPOT(+) results. Fifteen patients (18.5 %) had TST(+)/TSPOT(+) results, and 51 (63.0 %) had TST(-)/TSPOT(-) results (agreement = 81.5 %; kappa = .54 [95 % CI, .34-.74; P < .001]). Each TSPOT(+) and TST(+) results were independently associated with immigrant status and prior residence in a TB prevalent country after adjustment for immunosuppressive therapy: Adjusted OR(TSPOT+)=6.6 (95 % CI, 1.2-123.3; P = .027); and adjusted OR(TST+)=11.2 (95 % CI, 2.0-209.5; P = .003). Seven out of 10 TST(+)/TSPOT(-) cases had a TST ≥15 mm induration, including three cases with history of TST conversion.

CONCLUSIONS

TST(+) and TSPOT(+) results predict risk factors associated with LTBI independent of immunosuppressive IMT. Some TST(+)/TSPOT(-) results were unlikely to be false-negatives. The combined use of TST and TSPOT appears to be a reasonable diagnostic strategy to evaluate for LTBI in this population.

Implementation of new TB screening requirements for U.S.-bound immigrants and refugees - 2007-2014

For more than two decades, as the number of tuberculosis (TB) cases overall in the United States has declined, the proportion of cases among foreign-born persons has increased. In 2013, the percentage of TB cases among those born outside the country was 64.6%. To address this trend, CDC has developed strategies to identify and treat TB in U.S.-bound immigrants and refugees overseas. Each year, approximately 450,000 persons are admitted to the United States on an immigrant visa, and 50,000-70,000 are admitted as refugees. Applicants for either an immigrant visa or refugee status are required to undergo a medical examination overseas before being allowed to travel to the United States. CDC is the federal agency with regulatory oversight of the overseas medical examination, and panel physicians appointed by the U.S. Department of State perform the examinations in accordance with Technical Instructions (TI) provided by CDC's Division of Global Migration and Quarantine (DGMQ). Beginning in 1991, the algorithm for TB TI relied on chest radiographs for applicants aged ≥15 years, followed by sputum smears for those with findings suggestive of TB; no additional diagnostics were used. In 2007, CDC issued enhanced standards for TB diagnosis and treatment, including the addition of sputum cultures (which are more sensitive than smears) as a diagnostic tool and treatment delivered as directly observed therapy (DOT). This report summarizes worldwide implementation of the new screening requirements since 2007. In 2012, the year for which the most recent data are available, 60% of the TB cases diagnosed were in persons with smear-negative, but culture-positive, test results. The results demonstrate that rigorous diagnostic and treatment programs can be implemented in areas with high TB incidence overseas.

Persistent latent tuberculosis reactivation risk in United States immigrants

RATIONALE

Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB.

OBJECTIVES

Estimate reactivation and imported TB in an immigrant cohort.

METHODS

We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001-2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival.

MEASUREMENTS AND MAIN RESULTS

Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2-9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1-9.

CONCLUSIONS

High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival.

Tuberculosis screening by tuberculosis skin test or QuantiFERON-TB Gold In-Tube Assay among an immigrant population with a high prevalence of tuberculosis and BCG vaccination

RATIONALE

Each year 1 million persons acquire permanent U.S. residency visas after tuberculosis (TB) screening. Most applicants undergo a 2-stage screening with tuberculin skin test (TST) followed by CXR only if TST-positive at > 5 mm. Due to cross reaction with bacillus Calmette-Guérin (BCG), TST may yield false positive results in BCG-vaccinated persons. Interferon gamma release assays exclude antigens found in BCG. In Vietnam, like most high TB-prevalence countries, there is universal BCG vaccination at birth.

OBJECTIVES

1. Compare the sensitivity of QuantiFERON-TB Gold In-Tube Assay (QFT) and TST for culture-positive pulmonary TB. 2. Compare the age-specific and overall prevalence of positive TST and QFT among applicants with normal and abnormal CXR.

METHODS

We obtained TST and QFT results on 996 applicants with abnormal CXR, of whom 132 had TB, and 479 with normal CXR.

RESULTS

The sensitivity for tuberculosis was 86.4% for QFT; 89.4%, 81.1%, and 52.3% for TST at 5, 10, and 15 mm. The estimated prevalence of positive results at age 15-19 years was 22% and 42% for QFT and TST at 10 mm, respectively. The prevalence increased thereafter by 0.7% year of age for TST and 2.1% for QFT, the latter being more consistent with the increase in TB among applicants.

CONCLUSIONS

During 2-stage screening, QFT is as sensitive as TST in detecting TB with fewer requiring CXR and being diagnosed with LTBI. These data support the use of QFT over TST in this population.

Educating international students about tuberculosis and infections associated with travel to visit friends and relatives (VFR-travel)

BACKGROUND

International students in Victoria, Australia, originate from over 140 different countries. They are over-represented in disease notifications for tuberculosis and travel-associated infections, including enteric fever, hepatitis A, and malaria. We describe a public health initiative aimed to increase awareness of these illnesses among international students and their support staff.

METHODS

We identified key agencies including student support advisors, medical practitioners, health insurers, and government and professional organisations. We developed health education materials targeting international students regarding tuberculosis and travel-related infections to be disseminated via a number of different media, including electronic and printed materials. We sought informal feedback from personnel in all interested agencies regarding the materials developed, their willingness to deliver these materials to international students, and their preferred media for disseminating these materials.

RESULTS

Education institutions with dedicated international student support staff and on-campus health clinics were more easily engaged to provide feedback and disseminate the health education materials than institutions without such dedicated personnel. Response to contacting off-campus medical practices was poor. Delivery of educational materials via electronic and social media was preferred over face-to-face education.

CONCLUSIONS

It is feasible to provide health education messages targeting international students for dissemination via appropriately-staffed educational institutions. This initiative could be expanded in terms of age-group, geographic range, and health issues to be targeted.

Predicting U.S. tuberculosis case counts through 2020

In 2010, foreign-born persons accounted for 60% of all tuberculosis (TB) cases in the United States. Understanding which national groups make up the highest proportion of TB cases will assist TB control programs in concentrating limited resources where they can provide the greatest impact on preventing transmission of TB disease. The objective of our study was to predict through 2020 the numbers of U.S. TB cases among U.S.-born, foreign-born and foreign-born persons from selected countries of birth. TB case counts reported through the National Tuberculosis Surveillance System from 2000–2010 were log-transformed, and linear regression was performed to calculate predicted annual case counts and 95% prediction intervals for 2011–2020. Data were analyzed in 2011 before 2011 case counts were known. Decreases were predicted between 2010 observed and 2020 predicted counts for total TB cases (11,182 to 8,117 [95% prediction interval 7,262–9,073]) as well as TB cases among foreign-born persons from Mexico (1,541 to 1,420 [1,066–1,892]), the Philippines (740 to 724 [569–922]), India (578 to 553 [455–672]), Vietnam (532 to 429 [367–502]) and China (364 to 328 [249–433]). TB cases among persons who are U.S.-born and foreign-born were predicted to decline 47% (4,393 to 2,338 [2,113–2,586]) and 6% (6,720 to 6,343 [5,382–7,476]), respectively. Assuming rates of declines observed from 2000–2010 continue until 2020, a widening gap between the numbers of U.S.-born and foreign-born TB cases was predicted. TB case count predictions will help TB control programs identify needs for cultural competency, such as languages and interpreters needed for translating materials or engaging in appropriate community outreach.