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Objective: Case investigation and contact tracing (CI/CT) are fundamental public health efforts widely used during the COVID-19 pandemic to mitigate transmission. This study investigated how state, local, and tribal public health departments used CI/CT during the COVID-19 pandemic, including CI/CT methodology, staffing models, training and support, and efforts to identify or prioritize populations disproportionately affected by COVID-19., Methods: During March and April 2022, we conducted key informant interviews with up to 3 public health officials from 43 state, local, and tribal public health departments. From audio-recorded and transcribed interviews, we used the framework method to analyze key themes., Results: Major adjustments to CI/CT protocols during the pandemic included (1) prioritizing populations for outreach; (2) implementing automated outreach for nonprioritized groups, particularly during COVID-19 surges; (3) discontinuing contact tracing and focusing exclusively on case investigation; and (4) adding innovations to provide additional support. Key informants also discussed the utility of having backup staffing to support overwhelmed public health departments and spoke to the difficulty in "right-sizing" the public health workforce, with COVID-19 surges leaving public health departments understaffed as case rates rose and overstaffed as case rates fell., Conclusions: When addressing future epidemics or outbreaks, public health officials should consider strategies that improve the effectiveness of CI/CT efforts over time, such as prioritizing populations based on disproportionate risk, implementing automated outreach, developing models that provide flexible additional staffing resources as cases rise and fall among local public health departments, incorporating demographic data in laboratory reporting, providing community connections and support, and having a system of self-notification of contacts., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Using a nationally representative panel survey, we examined isolation behaviors among persons in the United States who had positive SARS-CoV-2 test results during January 2021-March 2022. Compared with persons who received provider-administered results, persons with home-based results had 29% (95% CI 5%-47%) lower odds of following isolation recommendations.

Background: Public health programs varied in ability to reach people with coronavirus disease 2019 (COVID-19) and their contacts to encourage separation from others. For both adult case patients with COVID-19 and their contacts, we estimated the impact of contact tracing activities on separation behaviors from January 2020 until March 2022., Methods: We used a probability-based panel survey of a nationally representative sample to gather data for estimates and comparisons., Results: An estimated 64 255 351 adults reported a positive severe acute respiratory syndrome coronavirus 2 test result; 79.6% isolated for ≥5 days, 60.2% isolated for ≥10 days, and 79.2% self-notified contacts. A total of, 24 057 139 (37.7%) completed a case investigation, and 46.2% of them reported contacts to health officials. More adults who completed a case investigation isolated than those who did not complete a case investigation (≥5 days, 82.6% vs 78.2%, respectively; ≥10 days, 69.8% vs 54.8%; both P < .05). A total of 84 946 636 adults were contacts of a COVID-19 case patient. Of these, 73.1% learned of their exposure directly from a case patient; 49.4% quarantined for ≥5 days, 18.7% quarantined for ≥14 days, and 13.5% completed a contact tracing call. More quarantined among those who completed a contact tracing call than among those who did not complete a tracing call (≥5 days, 61.2% vs 48.5%, respectively; ≥14 days, 25.2% vs 18.0%; both P < .05)., Conclusions: Engagement in contact tracing was positively correlated with isolation and quarantine. However, most adults with COVID-19 isolated and self-notified contacts regardless of whether the public health workforce was able to reach them. Identifying and reaching contacts was challenging and limited the ability to promote quarantining, and testing., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2023.)

Seventy percent of tuberculosis (TB) cases in the United States occur among non-US-born persons; cases usually result from reactivation of latent TB infection (LTBI) likely acquired before the person's US arrival. We conducted a prospective study among US immigrant visa applicants undergoing the required overseas medical examination in Vietnam. Consenting applicants >15 years of age were offered an interferon-γ release assay (IGRA); those 12-14 years of age received an IGRA as part of the required examination. Eligible participants were offered LTBI treatment with 12 doses of weekly isoniazid and rifapentine. Of 5,311 immigrant visa applicants recruited, 2,438 (46%) consented to participate; 2,276 had an IGRA processed, and 484 (21%) tested positive. Among 452 participants eligible for treatment, 304 (67%) initiated treatment, and 268 (88%) completed treatment. We demonstrated that using the overseas medical examination to provide voluntary LTBI testing and treatment should be considered to advance US TB elimination efforts.

Context: The implementation of case investigation and contact tracing (CICT) for controlling COVID-19 (caused by SARS-CoV-2 virus) has proven challenging due to varying levels of public acceptance and initially constrained resources, especially enough trained staff. Evaluating the impacts of CICT will aid efforts to improve such programs., Objectives: Estimate the number of COVID-19 cases and hospitalizations averted by CICT and identify CICT processes that could improve overall effectiveness., Design: We used data on the proportion of cases interviewed, contacts notified or monitored, and days from testing to case and contact notification from 14 jurisdictions to model the impact of CICT on cumulative case counts and hospitalizations over a 60-day period. Using the Centers for Disease Control and Prevention's COVIDTracer Advanced tool, we estimated a range of impacts by assuming either contacts would quarantine only if monitored or would do so upon notification of potential exposure. We also varied the observed program metrics to assess their relative influence., Results: Performance by jurisdictions varied widely. Jurisdictions isolated between 12% and 86% of cases (including contacts that became cases) within 6 to 10 days after infection. We estimated that CICT-related reductions in transmission ranged from 0.4% to 32%. For every 100 remaining cases after other nonpharmaceutical interventions were implemented, CICT averted between 4 and 97 additional cases. Reducing time to case isolation by 1 day increased averted case estimates by up to 15 percentage points. Increasing the proportion of cases interviewed or contacts notified by 20 percentage points each resulted in at most 3 or 6 percentage point improvements in averted cases., Conclusions: We estimated that CICT reduced the number of COVID-19 cases and hospitalizations among all jurisdictions studied. Reducing time to isolation produced the greatest improvements in impact of CICT., Competing Interests: No conflicts of interest to report.

Importance: Contact tracing is a multistep process to limit SARS-CoV-2 transmission. Gaps in the process result in missed opportunities to prevent COVID-19., Objective: To quantify proportions of cases and their contacts reached by public health authorities and the amount of time needed to reach them and to compare the risk of a positive COVID-19 test result between contacts and the general public during 4-week assessment periods., Design, Setting, and Participants: This cross-sectional study took place at 13 health departments and 1 Indian Health Service Unit in 11 states and 1 tribal nation. Participants included all individuals with laboratory-confirmed COVID-19 and their named contacts. Local COVID-19 surveillance data were used to determine the numbers of persons reported to have laboratory-confirmed COVID-19 who were interviewed and named contacts between June and October 2020., Main Outcomes and Measures: For contacts, the numbers who were identified, notified of their exposure, and agreed to monitoring were calculated. The median time from index case specimen collection to contact notification was calculated, as were numbers of named contacts subsequently notified of their exposure and monitored. The prevalence of a positive SARS-CoV-2 test among named and tested contacts was compared with that jurisdiction's general population during the same 4 weeks., Results: The total number of cases reported was 74 185. Of these, 43 931 (59%) were interviewed, and 24 705 (33%) named any contacts. Among the 74 839 named contacts, 53 314 (71%) were notified of their exposure, and 34 345 (46%) agreed to monitoring. A mean of 0.7 contacts were reached by telephone by public health authorities, and only 0.5 contacts per case were monitored. In general, health departments reporting large case counts during the assessment (≥5000) conducted smaller proportions of case interviews and contact notifications. In 9 locations, the median time from specimen collection to contact notification was 6 days or less. In 6 of 8 locations with population comparison data, positive test prevalence was higher among named contacts than the general population., Conclusions and Relevance: In this cross-sectional study of US local COVID-19 surveillance data, testing named contacts was a high-yield activity for case finding. However, this assessment suggests that contact tracing had suboptimal impact on SARS-CoV-2 transmission, largely because 2 of 3 cases were either not reached for interview or named no contacts when interviewed. These findings are relevant to decisions regarding the allocation of public health resources among the various prevention strategies and for the prioritization of case investigations and contact tracing efforts.

A review of 26 tuberculosis outbreaks in the United States (2002-2011) showed that initial source case-patients had long infectious periods (median 10 months) and were characterized by substance abuse, incarceration, and homelessness. Improved timeliness of diagnosis and thorough contact investigations for such cases may reduce the risk for outbreaks.

Background: Excess alcohol use among tuberculosis (TB) patients complicates TB control strategies., Objectives: To characterize the role of excess alcohol use in TB control, we describe the epidemiology of excess alcohol use and TB in the United States among those aged ⩾15 years., Design: Using data reported to the National Tuberculosis Surveillance System, 1997-2012, we examined associations between excess alcohol use and TB treatment outcomes and markers for increased transmission (involvement in a local genotype cluster of cases) using multivariate logistic regression. We used Cox proportional hazards regression analysis to examine the relationship between excess alcohol use and the rate of conversion from positive to negative in sputum culture results., Results: Excess alcohol use was documented for 31 207 (15.1%) of 207 307 patients. Prevalence of excess alcohol use was greater among male patients (20.6%) and US-born patients (24.6%). Excess alcohol use was associated with a positive sputum smear result (aOR 1.23, 95%CI 1.18-1.28) and death during treatment (vs. completion of treatment) (aOR 1.16, 95%CI 1.10-1.22). The rate of culture conversion was higher among patients without excess alcohol use (adjusted hazard ratio 1.20, 95%CI 1.18-1.23)., Conclusions: Excess alcohol use was common among patients with TB, and was associated with TB transmission, lower rates of sputum culture conversion, and greater mortality.

Setting: Mycobacterium tuberculosis comprises four principal genetic lineages: one evolutionarily ancestral (Indo-Oceanic) and three modern. Whether response to tuberculosis (TB) treatment differs among the lineages is unknown., Objective: To examine the association between M. tuberculosis lineage and time to sputum culture conversion in response to standard first-line drug therapy., Design: We conducted an exploratory retrospective cohort analysis of time to sputum culture conversion among pulmonary tuberculosis (PTB) cases reported in the United States from 2004 to 2007., Results: The analysis included 13,170 PTB cases with no documented resistance to first-line drugs who received a standard four-drug treatment regimen. Among cases with baseline positive sputum smear results, relative to cases with Euro-American lineage, cases with Indo-Oceanic lineage had higher adjusted hazards of sputum culture conversion (aHR 1.32, 95%CI 1.20-1.45), whereas cases with East-African-Indian or East-Asian lineage did not differ (aHR 1.05, 95%CI 0.88-1.25 and aHR 0.99, 95%CI 0.91-1.07, respectively). Among cases with baseline negative sputum smear results, time to sputum culture conversion did not differ by lineage., Conclusion: Although these results are exploratory, they suggest that the eradication of viable bacteria may occur sooner among cases with Indo-Oceanic lineage than among those with one of the three modern lineages. Prospective studies of time to sputum culture conversion by lineage are required.

To determine the proportion of reported tuberculosis (TB) cases due to recent transmission in the United States, we conducted a cross-sectional study to examine culture-positive TB cases with complete genotype results (spoligotyping and 12-locus mycobacterial interspersed repetitive unit-variable-number tandem repeat typing) reported during January 2005-December 2009. Recently transmitted cases were defined as cases with matching results reported within statistically significant geospatial zones (identified by a spatial span statistic within a sliding 3-year window). Approximately 1 in 4 TB cases reported in the United States may be attributed to recent transmission. Groups at greatest risk for recent transmission appear to be men, persons born in the United States, members of a minority race or ethnic group, persons who abuse substances, and the homeless. Understanding transmission dynamics and establishing strategies for rapidly detecting recent transmission among these populations are essential for TB elimination in the United States.

Background: Genotyping of Mycobacterium tuberculosis has revealed 4 major phylogenetic lineages with differential distribution worldwide. It is not clear whether different lineages are associated with different sites of infection (eg, pulmonary tuberculosis versus extrapulmonary tuberculosis). We sought to determine whether M. tuberculosis lineage is associated with the site of tuberculosis disease., Methods: We conducted a cross-sectional analysis of all culture-confirmed cases of tuberculosis with routinely determined M. tuberculosis spoligotype-defined lineage reported to the US National Tuberculosis Surveillance System from 2004 through 2008. Odds ratios (ORs) were used to assess the relation between disease site and M. tuberculosis lineage, after adjustment for age, sex, human immunodeficiency virus infection status, region of birth, and race/ethnicity., Results: Of 53972 reported culture-positive tuberculosis cases, 32000 (59.3%) were cases of M. tuberculosis that included complete spoligotype-based data on lineage. Of these, 23844 (74.5%) were exclusively pulmonary, 5085 (15.9%) were exclusively extrapulmonary, and 3071 (9.6%) were combined pulmonary and extrapulmonary. The percentages of tuberculosis cases that were exclusively extrapulmonary differed by lineage: East Asian, 13.0%; Euro-American, 13.8%; Indo-Oceanic, 22.6%; and East-African Indian, 34.3%. Compared with East Asian lineage, the odds of exclusively extrapulmonary tuberculosis relative to exclusively pulmonary tuberculosis were greater for Euro-American (adjusted OR, 1.3; 95% confidence interval [CI], 1.1-1.4), Indo-Oceanic (adjusted OR, 1.7; 95% CI, 1.5-1.9), and East-African Indian (adjusted OR, 1.6; 95% CI, 1.4-1.9) lineages., Conclusions: Phylogenetic lineage of M. tuberculosis is associated with the site of tuberculosis disease.

To understand circumstances of tuberculosis transmission that strain public health resources, we systematically reviewed Centers for Disease Control and Prevention (CDC) staff reports of US outbreaks in which CDC participated during 2002-2008 that involved ≥3 culture-confirmed tuberculosis cases linked by genotype and epidemiology. Twenty-seven outbreaks, representing 398 patients, were reviewed. Twenty-four of the 27 outbreaks involved primarily US-born patients; substance abuse was another predominant feature of outbreaks. Prolonged infectiousness because of provider- and patient-related factors was common. In 17 outbreaks, a drug house was a notable contributing factor. The most frequently documented intervention to control the outbreak was prioritizing contacts according to risk for infection and disease progression to ensure that the highest risk contacts were completely evaluated. US-born persons with reported substance abuse most strongly characterized the tuberculosis outbreaks in this review. Substance abuse remains one of the greatest challenges to controlling tuberculosis transmission in the United States.

Background: The true burden of reactivation of remote latent tuberculosis infection (reactivation TB) among foreign-born persons with tuberculosis (TB) within the United States is not known. Our study objectives were to estimate the proportion of foreign-born persons with TB due reactivation TB and to describe characteristics of foreign-born persons with reactivation TB., Methods: We conducted a cross-sectional study of patients with an M. tuberculosis isolate genotyped by the U.S. National TB Genotyping Service, 2005-2009. TB cases were attributed to reactivation TB if they were not a member of a localized cluster of cases. Localized clusters were determined by a spatial scan statistic of cases with isolates with matching TB genotype results. Crude odds ratios and 95% confidence intervals were used to assess relations between reactivation TB and select factors among foreign-born persons., Main Results: Among the 36,860 cases with genotyping and surveillance data reported, 22,151 (60%) were foreign-born. Among foreign-born persons with TB, 18,540 (83.7%) were attributed to reactivation TB. Reactivation TB among foreign-born persons was associated with increasing age at arrival, incidence of TB in the country of origin, and decreased time in the U.S. at the time of TB diagnosis., Conclusions: Four out of five TB cases among foreign-born persons can be attributed to reactivation TB and present the largest challenge to TB elimination in the U.S. TB control strategies among foreign-born persons should focus on finding and treating latent tuberculosis infection prior to or shortly after arrival to the United States and on reducing the burden of LTBI through improvements in global TB control.

Background: Tuberculosis (TB) control efforts are often ineffective in controlling TB among patients who use illicit drugs or abuse alcohol (substance abuse). This study examined the prevalence of substance abuse among TB cases reported in the United States and assessed the relation between substance abuse and indicators of TB transmission., Methods: A cross-sectional analysis was performed of data on US TB cases in patients 15 years or older reported from 1997 through 2006. Analyses included number and proportion of patients with TB characterized by substance abuse and associations between substance abuse, sputum smear status, treatment failure, and inclusion in a county-level genotype cluster., Results: Of 153,268 patients with TB, 28,650 (18.7%) reported substance abuse, including 22,293 of 76,816 US-born patients (29.0%). Multivariate analysis showed that, among patients negative for human immunodeficiency virus, odds of sputum smear-positive disease were 1.8 (99% confidence interval [CI], 1.7-1.9) times greater among those who reported substance abuse; this association was weaker among patients with human immunodeficiency virus infection (odds ratio [OR], 1.2; 99% CI, 1.1-1.4). Among female patients, odds of treatment failure were 2.4 (99% CI, 1.9-3.0) times greater among those who reported substance abuse. The association was weaker among male patients (OR, 1.5; 99% CI, 1.3-1.7). Patients who abused substances were more likely to be involved in a county-level genotype cluster (US-born: OR, 2.3; 99% CI, 2.0-2.7; foreign-born: 1.5; 1.2-2.0)., Conclusions: Substance abuse is the most commonly reported behavioral risk factor among patients with TB in the United States. Patients who abuse substances are more contagious (eg, smear positive) and remain contagious longer because treatment failure presumably extends periods of infectiousness. Increased transmission is consistent with our finding that patients who abuse substances were more likely to be involved in a localized genotype cluster, which can represent recent transmission.

In January 2005, tuberculosis (TB), including multidrug-resistant TB (MDR TB), was reported among Hmong refugees who were living in or had recently immigrated to the United States from a camp in Thailand. We investigated TB and drug resistance, enhanced TB screenings, and expanded treatment capacity in the camp. In February 2005, 272 patients with TB (24 MDR TB) remained in the camp. Among 17 MDR TB patients interviewed, 13 were found to be linked socially. Of 23 MDR TB isolates genotyped, 20 were similar according to 3 molecular typing methods. Before enhanced screening was implemented, 46 TB cases (6 MDR TB) were diagnosed in the United States among 9,455 resettled refugees. After enhanced screening had begun, only 4 TB cases (1 MDR TB), were found among 5,705 resettled refugees. An MDR TB outbreak among US-bound refugees led to importation of disease; enhanced pre-immigration TB screening and treatment decreased subsequent importation.

Pulmonary tuberculosis (TB) was diagnosed in a sailor aboard the U.S.S. Ronald Reagan; an investigation was conducted to determine a screening strategy for 1,172 civilian passengers who were aboard during a temporary guest rider program. Sailors were screened for latent TB infection (LTBI) and TB disease. A case-control study was conducted among sailors to determine factors associated with new LTBI. No secondary TB disease was identified; 13% of close contacts had new LTBI. Factors associated with new LTBI among sailors were having been born outside the United States (adjusted odds ratio = 2.80; 95% confidence interval, 1.55--5.07) and being a carrier air wing member (adjusted odds ratio = 2.89; 95% confidence interval, 1.83--4.58). Among 38 civilian passengers berthed near the patient, 1 (3%) had LTBI. The investigation results indicated that Mycobacterium tuberculosis transmission was minimal and eliminated unnecessary TB screening for 1,134 civilians which saved public health resources.

Purpose: To examine the relationship between number of sexual partners and selected health risk behaviors in a statewide sample of public high school students., Methods: The Centers for Disease Control and Prevention Youth Risk Behavior Survey was used to secure usable sexual risk-taking, substance use, and violence/aggression data from 3805 respondents. Because simple polychotomous logistic regression analysis revealed a significant Race x Gender interaction, subsequent multivariate models were constructed separately for each race-gender group. Odds ratios and 95% confidence intervals was calculated from polychotomous logistic regression models for number of sexual intercourse partners and their potential risk behavior correlates., Results: An increased number of sexual intercourse partners were correlated with a cluster of risk behaviors that place adolescents at risk for unintended pregnancy, human immunodeficiency virus/acquired immunodeficiency syndrome, and other sexually transmitted infections. For Black females, alcohol, tobacco, marijuana use, and dating violence behaviors were the strongest predictors of an increased number of sexual partners; white females had similar predictors with the addition of physical fighting. For white males, alcohol, tobacco, marijuana use, physical fighting, carrying weapons, and dating violence were the strongest predictors of an increased number of sexual intercourse partners. Black males had similar predictors with the addition of binge alcohol use., Conclusion: Prevention of adolescent sexual and other health risk behaviors calls for creative approaches in school and community settings and will require long-term intervention strategies focused on adolescent behavior changes and environmental modifications.