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HIV-positive pregnant women who are initiated on lifelong antiretroviral therapy (ART) and isoniazid preventive therapy (IPT) have lower adherence rates after delivery. We quantified maternal motivation to take preventive therapy before and after delivery among pregnant women newly diagnosed with HIV. We enrolled pregnant women (≥ 18 years) with a recent HIV diagnosis (< 6 months) at 14 public primary health clinics in Matlosana, South Africa and followed them in the postpartum period. Participants received eight choice tasks comparing two mutually exclusive sub-sets of seven possible benefits related to preventive therapy identified through literature reviews and key informant interviews. Data was analyzed using conditional logit regression in the antepartum versus postpartum periods. Coefficients are reported with 95% confidence intervals (CI). Sixty-five women completed surveys both at enrollment and in the postpartum period. All women were already on ART, while 21 (32%) were receiving IPT at enrollment. The mean CD4 count was 436 (± 246) cells/mm 3 . In the antepartum period, preventing HIV transmission to partners was the most important benefit (coefficients (ß) = 0.87, 95% CI 0.64, 1.11), followed by keeping healthy for family (ß = 0.75, 95% CI 0.52, 0.97). Such prioritization significantly decreased in the postpartum period (p < 0.001). Compared to other motivators, keeping a high CD4 count was least prioritized in the antepartum period (ß = 0.19, 95% CI - 0.04, 0.43) but was most prioritized in the postpartum period (ß = 0.39, 95% CI 0.21, 0.57). These results highlight that messages on family might be particularly salient in the antepartum period, and keeping CD4 count high in the postpartum period. Understanding maternal motivation may help to design targeted health promotion messages to HIV-positive women around the time of delivery.

Although less well-recognized than for other infectious diseases, heterogeneity is a defining feature of tuberculosis (TB) epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment, and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming that average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants, or comorbidities could improve efficiency, but raise ethical and equity considerations., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America.)

Drug-resistant tuberculosis (DR-TB) is challenging to diagnose, treat, and prevent, but this situation is slowly changing. If the world is to drastically reduce the incidence of DR-TB, we must stop creating new DR-TB as an essential first step. The DR-TB epidemic that is ongoing should also be directly addressed. First-line drug resistance must be rapidly detected using universal molecular testing for resistance to at least rifampin and, preferably, other key drugs at initial TB diagnosis. DR-TB treatment outcomes must also improve dramatically. Effective use of currently available, new, and repurposed drugs, combined with patient-centered treatment that aids adherence and reduces catastrophic costs, are essential. Innovations within sight, such as short, highly effective, broadly indicated regimens, paired with point-of-care drug susceptibility testing, could accelerate progress in treatment outcomes. Preventing or containing resistance to second-line and novel drugs is also critical and will require high-quality systems for diagnosis, regimen selection, and treatment monitoring. Finally, earlier detection and/or prevention of DR-TB is necessary, with particular attention to airborne infection control, case finding, and preventive therapy for contacts of patients with DR-TB. Implementing these strategies can overcome the barrier that DR-TB represents for global TB elimination efforts, and could ultimately make global elimination of DR-TB (fewer than one annual case per million population worldwide) attainable. There is a strong cost-effectiveness case to support pursuing DR-TB elimination; however, achieving this goal will require substantial global investment plus political and societal commitment at national and local levels.

Background: There is a dearth of comparative effectiveness research examining the implementation of different strategies for active tuberculosis (TB) case finding, particularly in rural settings, which represent 60% of the population of sub-Saharan Africa., Methods and Findings: We conducted a pragmatic, cluster-randomized comparative effectiveness trial of two TB case finding strategies (facility-based screening and contact tracing) in 56 public primary care clinics in two largely rural districts of Limpopo Province, South Africa. In the facility-based screening arm, sputum Xpert MTB/RIF was performed on all patients presenting (for any reason) with TB symptoms to 28 study clinics, and no contact tracing was performed. In the contact-tracing arm, contacts of patients with active TB were identified (via household tracing in 14 clinics and using small monetary incentives in the other 14 clinics), screened for TB symptoms, and offered Xpert MTB/RIF testing. The primary outcome was the number of newly identified patients with TB started on treatment. The analysis used multivariable Poisson regression adjusted for historical clinic-level TB case volumes and district. The trial was registered with ClinicalTrials.gov (NCT02808507). From July 18, 2017, to January 17, 2019, a total of 3,755 individuals started TB treatment across 56 study clinics in the 18-month period. Clinic characteristics and clinic-level averages of patient characteristics were similar across the two arms: 40/56 (71%) clinics were in a rural location, 2,136/3,655 (58%) patients were male, and 2,243 (61%) were HIV positive. The treatment initiation ratio comparing the yield of TB patients started on treatment in the facility-based arm compared to that from the contact-tracing arm was 1.04 (95% confidence interval [CI] 0.83-1.30, p = 0. 73). In the contact-tracing arm, 1,677 contacts of 788 new TB index patients were screened, yielding 12 new patients with TB. Prespecified subgroup analyses resulted in similar results, with estimated treatment initiation ratios of 0.96 (95% CI 0.64-1.27; p = 0.78) and 1.23 (95% CI 0.87-1.59; p = 0.29) among historically smaller and historically larger clinics, respectively. This ratio was 1.02 (95% CI 0.66-1.37; p = 0.93) and 1.08 (95% CI 0.74-1.42; p = 0.68) in the Vhembe and Waterberg districts, respectively. The estimated treatment initiation ratio was unchanged in sensitivity analyses excluding 24 records whose TB registration numbers could not be verified (1.03, 95% CI 0.82-1.29; p = 0.78) and excluding transfers-in (1.02, 95% CI 0.80-1.29; p = 0.71). Study limitations include the possibility of imbalance on cluster size owing to changes in catchment population over time and the inability to distinguish the independent effects of the two contact investigation strategies., Conclusions: Contact tracing based on symptom screening and Xpert MTB/RIF testing did not increase the rate of treatment initiation for TB relative to the less resource-intensive approach of facility-based screening in this rural sub-Saharan setting., Trial Registration: ClinicalTrials.gov NCT02808507., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: NM's institution, The Perinatal HIV Research Unit, has received grants from Roche and Becton-Dickinson for collection of specimens for novel tests for TB.

Background: The mass scale-up of antiretroviral therapy (ART) in Zambia has taken place in the context of limited infrastructure and human resources resulting in many operational side-effects. In this study, we aimed to empirically measure current workload of ART clinic staff and patient wait times and service utilization., Methods: We conducted time and motion (TAM) studies from both the healthcare worker (HCW) and patient perspectives at 10 ART clinics throughout Zambia. Trained personnel recorded times for consecutive discrete activities based on direct observation of clinical and non-clinical activities performed by counselors, clinical officers, nurses, and pharmacy technicians. For patient TAM, we recruited consenting patients and recorded times of arrival and departure and major ART services utilized. Data from 10 clinics were pooled to evaluate median time per patient spent for each activity and patient duration of stay in the clinic., Results: The percentage of observed clinical time for direct patient interaction (median time per patient encounter) was 43.1% for ART counselors (4 min, interquartile range [IQR] 2-7), 46.1% for nurses (3 min, IQR 2-4), 57.2% for pharmacy technicians (2 min, IQR 1-2), and 78.5% for clinical officers (3 min, IQR 2-5). Patient workloads for HCWs were heaviest between 8 AM and 12 PM with few clinical activities observed after 2 PM. The length of patient visits was inversely associated with arrival time - patients arriving prior to 8 AM spent 61% longer at the clinic than those arriving after 8 AM (277 vs. 171 min). Overall, patients spent 219 min on average for non-clinical visits, and 244 min for clinical visits, but this difference was not significant in rural clinics. In comparison, total time patients spent directly with clinic staff were 9 and 12 min on average for non-clinical and clinical visits., Conclusion: Current Zambian ART clinic operations include substantial inefficiencies for both patients and HCWs, with workloads heavily concentrated in the first few hours of clinic opening, limiting HCW and patient interaction time. Use of a differentiated care model may help to redistribute workloads during operational hours and prevent backlogs of patients waiting for hours before clinic opening, which may substantially improve ART delivery in the Zambian context.

Rationale: Many high-burden countries are scaling-up Xpert MTB/RIF using a hub-and-spoke model. We evaluated the quality of care for patients undergoing TB evaluation at microscopy centers (spokes) linked to Xpert testing sites (hubs) in Uganda., Objectives: To characterize the extent to which patients were receiving care in accordance with international and national guidelines., Methods: We conducted a prospective cohort study of all adults with presumptive pulmonary TB at 24 health centers linked to Xpert testing sites. Health center staff photographed TB registers, and uploaded photos to a secure server bi-weekly. We assessed the proportion of patients (1) initiating testing; (2) completing testing; and (3) treated for confirmed TB within 14 days., Measurements and Main Results: Between January to December 2017, 6744 patients underwent evaluation for pulmonary TB. Only 1316 patients had sputum referred for Xpert testing, including 1075/3229 (33.3%) people living with HIV and 241/3515 (6.9%) without HIV. Of 119 patients confirmed to have TB by Xpert testing, 44 (36%) did not initiate treatment. There were significant losses along the entire diagnostic cascade of care, with only 5330/6744 (79.0%) patients having samples referred for sputum-based testing, 2978/5330 (55.9%) patients completing recommended testing if referred, and 313/418 (74.9%) patients initiating treatment within 14 days if confirmed to have TB., Conclusions: Although coverage of Xpert testing services across Uganda is high, the quality of care delivered to patients undergoing TB evaluation remains poor. Further research is needed to identify health system interventions to facilitate uptake of Xpert testing and high-quality care., (© 2019 The Authors.)

Background: Tuberculosis (TB) remains the leading cause of death among human immunodeficiency virus (HIV)-infected individuals globally. Screening for TB at the point of HIV diagnosis with a high-sensitivity assay presents an opportunity to reduce mortality., Methods: We performed a cluster randomized trial of TB screening among adults newly diagnosed with HIV in 12 primary health clinics in rural Thyolo, Malawi. Clinics were allocated in a 1:1 ratio to perform either point-of-care Xpert MTB/RIF assay (Xpert) or point-of-care light-emitting diode fluorescence microscopy (LED-FM) for individuals screening positive for TB symptoms. Asymptomatic participants were offered isoniazid preventive therapy in both arms. Investigators, but not clinic staff or participants, were masked to allocation. Our primary outcome was the incidence rate ratio (RR) of all-cause mortality within 12 months of HIV diagnosis., Results: Prevalent TB was diagnosed in 24 of 1001 (2.4%) individuals enrolled in clinics randomized to Xpert, compared with 10 of 841 (1.2%) in clinics randomized to LED-FM. All-cause mortality was 22% lower in the Xpert arm than in the LED-FM arm (6.7 vs 8.6 per 100 person-years; RR, 0.78 [95% confidence interval {CI}, .58-1.06]). A planned subgroup analysis suggested that participants with more advanced HIV (World Health Organization clinical stage 3 or 4) disease had lower mortality in clinics randomized to Xpert than to LED-FM (RR, 0.43 [95% CI, .22-.87])., Conclusions: In rural Malawi, using point-of-care Xpert MTB/RIF to test symptomatic patients for TB at the time of HIV diagnosis reduced all-cause 12-month mortality among individuals with advanced HIV., Clinical Trials Registration: NCT01450085., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objectives: Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) increase the risk of HIV transmission among men who have sex with men (MSM). Diagnosis of NG/CT may provide an efficient entry point for prevention of HIV through the delivery of pre-exposure prophylaxis (PrEP); however, the additional population-level impact of targeting PrEP to MSM diagnosed with NG/CT is unknown., Design: An agent-based simulation model of NG/CT and HIV cocirculation among MSM calibrated against census data, disease surveillance reports and the US National HIV Behavioral Surveillance study., Setting: Baltimore City, Maryland, USA., Interventions: PrEP implementation was modelled under three alternative scenarios: (1) PrEP delivery at NG/CT diagnosis (targeted delivery), (2) PrEP evaluation at NG/CT screening/testing and (3) PrEP evaluation in the general community (untargeted)., Main Outcome: The projected incidence of HIV after 20 years of PrEP delivery under two alternatives: when equal numbers of MSM are (1) screened for PrEP or (2) receive PrEP in each year., Results: Assuming 60% uptake and 60% adherence, targeting PrEP to MSM diagnosed with NG/CT could reduce HIV incidence among MSM in Baltimore City by 12.4% (95% uncertainty range (UR) 10.3% to 14.4%) in 20 years, relative to no PrEP. Expanding the coverage of NG/CT screening (such that individuals experience a 50% annual probability of NG/CT screening and evaluation for PrEP on NG/CT diagnosis) can further increase the impact of targeted PrEP to generate a 22.0% (95% UR 20.1% to 23.9%) reduction in HIV incidence within 20 years. When compared with alternative implementation scenarios, PrEP evaluation at NG/CT diagnosis increased impact of PrEP on HIV incidence by 1.5(95% UR 1.1 to 1.9) times relative to a scenario in which PrEP evaluation happened at the time of NG/CT screening/testing and by 1.6 (95% UR 1.2 to 2.2) times relative to evaluating random MSM from the community., Conclusions: Targeting MSM infected with NG/CT increases the efficiency and effectiveness of PrEP delivery. If high levels of sexually transmitted infection screening can be achieved at the community level, NG/CT diagnosis may be a highly effective entry point for PrEP initialisation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: The recommended tuberculosis (TB) intensified case finding (ICF) algorithm for people living with HIV (symptom-based screening followed by Xpert MTB/RIF [Xpert] testing) is insufficiently sensitive and results in unnecessary Xpert testing., Objectives: To evaluate whether novel ICF algorithms combining C-reactive protein (CRP)-based screening with urine Determine TB-LAM (TB-LAM), sputum Xpert, and/or sputum culture could improve ICF yield and efficiency., Methods: We compared the yield and efficiency of novel ICF algorithms inclusive of point-of-care CRP-based TB screening and confirmatory testing with urine TB-LAM (if CD4 count ≤100 cells/μl), sputum Xpert, and/or a single sputum culture among consecutive people living with HIV with CD4 counts less than or equal to 350 cells/μl initiating antiretroviral therapy in Uganda., Measurements and Main Results: Of 1,245 people living with HIV, 203 (16%) had culture-confirmed TB including 101 (49%) patients with CD4 counts less than or equal to 100 cells/μl. Compared with the current ICF algorithm, point-of-care CRP-based TB screening followed by Xpert testing had similar yield (56% [95% confidence interval, 49-63] vs. 59% [95% confidence interval, 51-65]) but consumed less than half as many Xpert assays per TB case detected (9 vs. 4). Addition of TB-LAM did not significantly increase diagnostic yield relative to the current ICF algorithm but provided same-day diagnosis for 26% of TB patients with advanced HIV. Addition of a single culture to TB-LAM and Xpert substantially improved ICF yield, identifying 78% of all TB cases., Conclusions: Point-of-care CRP-based screening can improve ICF efficiency among people living with HIV. Addition of TB-LAM and a single culture to Xpert confirmatory testing could enable HIV programs to increase the speed of TB diagnosis and ICF yield.

Objective: Both isoniazid preventive therapy (IPT) and antiretroviral therapy (ART) reduce tuberculosis risk in individuals living with HIV. We sought to estimate the broader, population-wide impact of providing a pragmatically implemented 12-month IPT regimen to ART recipients in a high-burden community., Design: Dynamic transmission model of a tuberculosis (TB)-HIV epidemic, calibrated to site-specific, historical epidemiologic and clinical trial data from Khayelitsha, South Africa., Methods: We projected the 5-year impact of delivering a 12-month IPT regimen community-wide to 85% of new ART initiators and 15%/year of those already on ART, accounting for IPT-attributable reductions in TB infection, progression, and transmission. We also evaluated scenarios of continuously-delivered IPT, ongoing ART scale-up, and lower tuberculosis incidence., Results: Under historical (early 2010) ART coverage, this ART-linked IPT intervention prevented one tuberculosis case per 18 [95% credible interval (CrI) 11-29] people treated. It lowered TB incidence by a projected 23% (95% CrI 14-30%) among people receiving ART, and by 5.2% (95% CrI 2.9-8.7%) in the total population. Continuous IPT reduced the number needed to treat to prevent one case of TB to 10 (95% CrI 7-16), though it required 74% more person-years of therapy (95% CrI 64-94%) to prevent one TB case, relative to 12-month therapy. Under expanding ART coverage, the tuberculosis incidence reduction achieved by 12-month IPT grew to 7.6% (95% CrI 4.3-12.6%). Effect sizes were similar in a simulated setting of lower TB incidence., Conclusions: IPT in conjunction with ART reduces tuberculosis incidence among those who receive therapy and has additional impact on tuberculosis transmission in the population.

As the leading infectious cause of death worldwide and the primary proximal cause of death in individuals living with HIV, tuberculosis remains a global concern. Existing tuberculosis control strategies that rely on passive case-finding appear insufficient to achieve targets for reductions in tuberculosis incidence and mortality. Active case-finding strategies aim to detect infectious individuals earlier in their infectious period to reduce onward transmission and improve treatment outcomes. Empirical studies of active case-finding have produced mixed results and determining how to direct active screening to those most at risk remains a topic of intense research. Our systematic review of literature evaluating the effects of geographically targeted tuberculosis screening interventions found three studies in low tuberculosis incidence settings, but none conducted in high tuberculosis incidence countries. We discuss open questions related to the use of spatially targeted approaches for active screening in countries where tuberculosis incidence is highest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

To find the millions of missed tuberculosis (TB) cases, national TB programs are under pressure to expand TB disease screening and to target populations with lower disease prevalence. Together with imperfect performance and application of existing diagnostic tools, including empirical diagnosis, broader screening risks placing individuals without TB on prolonged treatment. These false-positive diagnoses have profound consequences for TB patients and prevention efforts, yet are usually overlooked in policy decision making. In this article we describe the pathways to a false-positive TB diagnosis, including trade-offs involved in the development and application of diagnostic algorithms. We then consider the wide range of potential consequences for individuals, households, health systems, and reliability of surveillance data. Finally, we suggest practical steps that the TB community can take to reduce the frequency and potential harms of false-positive TB diagnosis and to more explicitly assess the trade-offs involved in the screening and diagnostic process.

Objective: To estimate the incremental cost-effectiveness of universal vs. test-directed treatment of latent tuberculous infection (LTBI) among human immunodeficiency virus (HIV) positive pregnant women in South Africa., Methods: We compared tuberculin skin test (TST) directed isoniazid preventive therapy (IPT) (TST placement with delivery of IPT to women with positive results) against QuantiFERON ® -TB Gold In-Tube (QGIT) directed IPT and universal IPT using decision analysis. Costs were measured empirically in six primary care public health clinics in Matlosana, South Africa. The primary outcome was the incremental cost-effectiveness ratio, expressed in 2016 US$ per disability-adjusted life-year (DALY) averted., Results: We estimated that 29.2 of every 1000 pregnant women would develop TB over the course of 1 year in the absence of IPT. TST-directed IPT reduced this number to 24.5 vs. 22.6 with QGIT-directed IPT and 21.0 with universal IPT. Universal IPT was estimated to cost $640/DALY averted (95% uncertainty range $44-$3146) relative to TST-directed IPT and was less costly and more effective (i.e., dominant) than QGIT-directed IPT. Cost-effectiveness was most sensitive to the probability of developing TB and LTBI prevalence., Conclusion: Providing IPT to all eligible women can be a cost-effective strategy to prevent TB among HIV-positive pregnant women in South Africa.

Background: Preexposure prophylaxis (PrEP) greatly reduces the risk of human immunodeficiency virus (HIV) acquisition, but its optimal delivery strategy remains uncertain. Clinics for sexually transmitted infections (STIs) can provide an efficient venue for PrEP delivery., Methods: To quantify the added value of STI clinic-based PrEP delivery, we used an agent-based simulation of HIV transmission among men who have sex with men (MSM). We simulated the impact of PrEP delivery through STI clinics compared with PrEP delivery in other community-based settings. Our primary outcome was the projected 20-year reduction in HIV incidence among MSM., Results: Assuming PrEP uptake and adherence of 60% each, evaluating STI clinic attendees and delivering PrEP to eligible MSM reduced HIV incidence by 16% [95% uncertainty range, 14%-18%] over 20 years, an impact that was 1.8 (1.7-2.0) times as great as that achieved by evaluating an equal number of MSM recruited from the community. Comparing strategies where an equal number of MSM received PrEP in each strategy (ie, evaluating more individuals for PrEP in the community-based strategy, because MSM attending STI clinics are more likely to be PrEP eligible), the reduction in HIV incidence under the STI clinic-based strategy was 1.3 (1.3-1.4) times as great as that of community-based delivery., Conclusions: Delivering PrEP to MSM who attend STI clinics can improve efficiency and effectiveness. If high levels of adherence can be achieved in this population, STI clinics may be an important venue for PrEP implementation.

Objectives: To illustrate the magnitude of between-state heterogeneities in tuberculosis (TB) incidence among US populations at high risk for TB that may help guide state-specific strategies for TB elimination., Methods: We used data from the National Tuberculosis Surveillance System and other public sources from 2011 to 2015 to calculate TB incidence in every US state among people who were non-US-born, had diabetes, or were HIV-positive, homeless, or incarcerated. We then estimated the proportion of TB cases that reflected the difference between each state's reported risk factor-specific TB incidence and the lowest incidence achieved among 4 states (California, Florida, New York, Texas). We reported these differences for the 4 states and also calculated and aggregated across all 50 states to quantify the total percentage of TB cases nationally that reflected between-state differences in risk factor-specific TB incidence., Results: On average, 24% of recent TB incidence among high-risk US populations reflected heterogeneity at the state level. The populations that accounted for the greatest percentage of heterogeneity-reflective cases were non-US-born individuals (51%) and patients with diabetes (24%)., Conclusions: State-level differences in TB incidence among key populations provide clues for targeting state-level interventions.

Introduction: Cost-effectiveness models for infectious disease interventions often require transmission models that capture the indirect benefits from averted subsequent infections. Compartmental models based on ordinary differential equations are commonly used in this context. Decision trees are frequently used in cost-effectiveness modeling and are well suited to describing diagnostic algorithms. However, complex decision trees are laborious to specify as compartmental models and cumbersome to adapt, limiting the detail of algorithms typically included in transmission models., Methods: We consider an approximation replacing a decision tree with a single holding state for systems where the time scale of the diagnostic algorithm is shorter than time scales associated with disease progression or transmission. We describe recursive algorithms for calculating the outcomes and mean costs and delays associated with decision trees, as well as design strategies for computational implementation. We assess the performance of the approximation in a simple model of transmission/diagnosis and its role in simplifying a model of tuberculosis diagnostics., Results: When diagnostic delays were short relative to recovery rates, our approximation provided a good account of infection dynamics and the cumulative costs of diagnosis and treatment. Proportional errors were below 5% so long as the longest delay in our 2-step algorithm was under 20% of the recovery time scale. Specifying new diagnostic algorithms in our tuberculosis model was reduced from several tens to just a few lines of code., Discussion: For conditions characterized by a diagnostic process that is neither instantaneous nor protracted (relative to transmission dynamics), this novel approach retains the advantages of decision trees while embedding them in more complex models of disease transmission. Concise specification and code reuse increase transparency and reduce potential for error.

Antiretroviral therapy (ART) and isoniazid preventive therapy (IPT) are important to reduce morbidity and mortality among people newly diagnosed of HIV. The successful uptake of ART and IPT requires a comprehensive understanding of patients' motivation to take such therapies. Partners also play an important role in the decision to be initiated and retained in care. We quantified patients' motivation to take preventive therapies (ART and IPT) and compared by partner HIV status among people newly diagnosed of HIV. We enrolled and surveyed adults (≥18 years) with a recent HIV diagnosis (<6 months) from 14 public primary care clinics in Matlosana, South Africa. Participants received eight forced-choice tasks comparing two mutually exclusive sub-sets of seven possible benefits related to preventive therapies. A linear probability model was fitted to estimate the probability of prioritizing each benefit. Tests of concordance were conducted across partner HIV status (no partner, HIV- or unknown, or HIV+). A total of 424 people completed surveys. At the time of interview, 272 (64%) were on ART and 334 (79%) had a partner or spouse. Keeping themselves healthy for their family was the most important motivator to take preventive therapies (p < 0.001). Preventing HIV transmission to partners was also highly prioritized among participants with current partners independent of partner's HIV status (p < 0.001), but it was least prioritized among those without current partners (p = 0.72). Keeping themselves healthy was less prioritized. We demonstrate that social responsibility such as supporting family and preventing HIV transmission to partners may pose greater motivation for ART and IPT initiation and adherence compared to individual health benefits. These messages should be emphasized to provide effective patient-centered care and counseling.

Background: A short-course regimen of 3 months of weekly rifapentine and isoniazid (3HP) has recently been recommended by the World Health Organization as an alternative to at least 6 months of daily isoniazid (isoniazid preventive therapy [IPT]) for prevention of tuberculosis (TB). The contexts in which 3HP may be cost-effective compared to IPT among people living with human immunodeficiency virus are unknown., Methods: We used a Markov state transition model to estimate the incremental cost-effectiveness of 3HP relative to IPT in high-burden settings, using a cohort of 1000 patients in a Ugandan HIV clinic as an emblematic scenario. Cost-effectiveness was expressed as 2017 US dollars per disability-adjusted life year (DALY) averted from a healthcare perspective over a 20-year time horizon. We explored the conditions under which 3HP would be considered cost-effective relative to IPT., Results: Per 1000 individuals on antiretroviral therapy in the reference scenario, treatment with 3HP rather than IPT was estimated to avert 9 cases of TB and 1 death, costing $9402 per DALY averted relative to IPT. Cost-effectiveness depended strongly on the price of rifapentine, completion of 3HP, and prevalence of latent TB. At a willingness to pay of $1000 per DALY averted, 3HP is likely to be cost-effective relative to IPT only if the price of rifapentine can be greatly reduced (to approximately $20 per course) and high treatment completion (85%) can be achieved., Conclusions: 3HP may be a cost-effective alternative to IPT in high-burden settings, but cost-effectiveness depends on the price of rifapentine, achievable completion rates, and local willingness to pay.

Introduction: Pregnant women newly diagnosed with HIV during pregnancy are often lost to follow up and their adherence rates drop after delivery. We quantified changes in priorities related to isoniazid preventive therapy (IPT) and antiretroviral therapy (ART) among pregnant women living with HIV., Methods: We enrolled pregnant women recently diagnosed with HIV from 14 primary health clinics during pregnancy and followed them after delivery in Matlosana, South Africa. Best-worst scaling (BWS) was used to determine the women's priorities out of 11 attributes related to preventive therapy in the ante- versus postpartum periods. Aggregate BWS scores were calculated based on the frequency with which participants selected each attribute as the best or worst among five options (across multiple choice sets). Individual BWS scores were also calculated and rescaled from 0 (always selected as worst) to 10 (always selected as best), and changes in BWS scores in the ante- versus postpartum periods were compared, using a paired t-test. Factors associated with the changes in BWS scores were examined in multiple linear regressions. Spearman's rho was used to compare the ranking of attributes., Results: Out of a total of 204 participants, 154 (75.5%) completed the survey in the postpartum at the median 15 (IQR: 11 to 27) weeks after delivery. Trust in healthcare providers was most highly prioritized both in the ante- (individual BWS Score = 7.34, SE = 0.13) and postpartum periods (BWS = 7.21 ± 0.11), followed by living a long life (BWS = 6.77 ± 0.09 in the ante- vs. BWS = 6.86 ± 0.10 in the postpartum). Prevention for infants' health was more prioritized in the post- (BWS = 6.54 ± 0.09) versus antepartum periods (BWS = 6.11 ± 0.10) (p = 0.05). This change was associated with IPT initiation at enrolment (regression coefficient = 0.78 ± 0.33, p = 0.001). Difficulty in daily pill-uptake was significantly more prioritized in the postpartum (BWS = 5.03 ± 0.11) than in the antepartum (BWS = 4.43 ± 0.10) (p < 0.01). Transportation cost and worry about side effects of pills were least prioritized. Overall ranking of attributes was similar in both time periods (spearman's rho = 0.90)., Conclusions: Comprehensive interventions to build trust in healthcare providers and support adherence may increase uptake of preventive therapy. Counselling needs to emphasize medication benefits for both maternal and infant health among HIV-positive pregnant women., (© 2018 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.)

Setting: To reduce the risk of tuberculosis (TB) among individuals with human immunodeficiency virus (HIV) infection, the World Health Organization recommends at least 6 months of isoniazid preventive therapy (IPT). Completion of IPT remains a major challenge in resource-limited settings., Objective: To evaluate predictors of IPT completion in individuals newly diagnosed with HIV., Design: Predictors of IPT completion among adults newly diagnosed with HIV in rural Malawi were evaluated using a multilevel logistic regression model., Results: Of 974 participants who screened negative for active TB and were started on IPT, 732 (75%) completed treatment. Only one IPT-eligible individual refused treatment. Participants who were aged <25 years (compared with those aged 45 years, adjusted OR [aOR] 0.33, 95%CI 0.18-0.60) and male (compared to non-pregnant females, aOR 0.57, 95%CI 0.37-0.88) had lower odds of IPT completion., Conclusion: IPT provision at the time of initial HIV diagnosis was highly acceptable in rural Malawi; three quarters of those who initiated IPT successfully completed therapy. We observed lower odds of completion among males and among female participants aged <25 years. Additional efforts may be needed to ensure IPT completion among males and young females who have recently been diagnosed with HIV.

Setting: Ten primary health clinics in rural Thyolo District, Malawi., Objective: Tuberculosis (TB) is a common initial presentation of human immunodeficiency virus (HIV) infection. We investigated the time from TB symptom onset to HIV diagnosis to describe TB health-seeking behaviour in adults newly diagnosed with HIV., Design: We asked adults (18 years) about the presence and duration of TB symptoms at the time of receiving a new HIV diagnosis. Associations with delayed health seeking (defined as >30 and >90 days from the onset of TB symptoms) were evaluated using multivariable logistic regression., Results: TB symptoms were reported by 416 of 1265 participants (33%), of whom 36% (150/416) had been symptomatic for >30 days before HIV testing. Most participants (260/416, 63%) were below the poverty line (US$0.41 per household member per day). Patients who first sought care from informal providers had an increased odds of delay of >30 days (adjusted odds ratio [aOR] 1.6, 95%CI 0.9-2.8) or 90 days (aOR 2.0, 95%CI 1.1-3.8)., Conclusions: Delayed health seeking for TB-related symptoms was common. Poverty was ubiquitous, but had no clear relationship to diagnostic delay. HIV-positive individuals who first sought care from informal providers were more likely to experience diagnostic delays for TB symptoms.

Social justice is the moral imperative to avoid and remediate unfair distributions of societal disadvantage. In priority setting in healthcare and public health, social justice reaches beyond fairness in the distribution of health outcomes and economic impacts to encompass fairness in the distribution of policy impacts upon other dimensions of well-being. There is an emerging awareness of the need for economic evaluation to integrate all such concerns. We performed a systematic review (1) to describe methodological solutions suitable for integrating social justice concerns into economic evaluation, and (2) to describe the challenges that those solutions face. To be included, publications must have captured fairness considerations that (a) involve cross-dimensional subjective personal life experience and (b) can be manifested at the level of subpopulations. We identified relevant publications using an electronic search in EMBASE, PubMed, EconLit, PsycInfo, Philosopher's Index, and Scopus, including publications available in English in the past 20 years. Two reviewers independently appraised candidate publications, extracted data, and synthesized findings in narrative form. Out of 2388 publications reviewed, 26 were included. Solutions sought either to incorporate relevant fairness considerations directly into economic evaluation or to report them alongside cost-effectiveness measures. The majority of reviewed solutions, if adapted to integrate social justice concerns, would require their explicit quantification. Four broad challenges related to the implementation of these solutions were identified: clarifying the normative basis; measuring and determining the relative importance of criteria representing that basis; combining the criteria; and evaluating trade-offs. All included solutions must grapple with an inherent tension: they must either face the normative and operational challenges of quantifying social justice concerns or accede to offering incomplete policy guidance. Interdisciplinary research and broader collaborations are crucial to address these challenges and to support due attention to social justice in priority setting., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: The National HIV/AIDS Strategy has set ambitious goals to improve the epidemic in the United States. However, there is a paucity of usable program-level benchmarks tied to population-level epidemiologic goals. Our objective was to define tangible benchmarks for annual rates along the care continuum that are likely to translate to meaningful reductions in incidence., Methods: We used a validated mathematical model of HIV transmission and care engagement to characterize care continuum parameters that would translate into 50% reductions in incidence by 2025, compared with a base case scenario of the current US care continuum. We generated a large pool of simulations in which rates of screening, linkage, and retention in care were varied across wide ranges to evaluate permutations that halved incidence by 2025., Results: Among all simulations, 7% achieved a halving of incidence. It was impossible for our simulations to achieve this target if the annual rate of disengagement from care exceeded 20% per year, even at high rates of care reengagement. When retention in care was 95% per year and people living with HIV (PLWH) out of care reengaged within 1.5 years (on average), the probability of halving incidence by 2025 was approximately 90%., Conclusions: HIV programs should aim to retain at least 95% of PLWH in care annually and reengage people living with HIV into care within an average of 1.5 years to achieve the goal of halving HIV incidence by 2025.

Background: Substantial individual heterogeneity exists in the clinical manifestations and duration of active tuberculosis. We sought to link the individual-level characteristics of tuberculosis disease to observed population-level outcomes., Methods: We developed an individual-based, stochastic model of tuberculosis disease in a hypothetical cohort of patients with smear-positive tuberculosis. We conceptualized the disease process as consisting of 2 states-progression and recovery-including transitions between the 2. We then used a Bayesian process to calibrate the model to clinical data from the prechemotherapy era, thus identifying the rates of progression and recovery (and probabilities of transition) consistent with observed population-level clinical outcomes., Results: Observed outcomes are consistent with slow rates of disease progression (median doubling time: 84 days, 95% uncertainty range 62-104) and a low, but nonzero, probability of transition from disease progression to recovery (median 16% per year, 95% uncertainty range 11%-21%). Other individual-level dynamics were less influential in determining observed outcomes., Conclusions: This simplified model identifies individual-level dynamics-including a long doubling time and low probability of immune recovery-that recapitulate population-level clinical outcomes of untreated tuberculosis patients. This framework may facilitate better understanding of the population-level impact of interventions acting at the individual host level., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Optimizing the use of new tools, such as vaccines, may play a crucial role in reaching global targets for tuberculosis (TB) control. Some of the most promising candidate vaccines target adults, although high-coverage mass vaccinations may be logistically more challenging among this population than among children. Vaccine-delivery strategies that target high-risk groups or settings might yield proportionally greater impact than do those that target the general population. We developed an individual-based TB transmission model representing a hypothetical population consisting of people who worked in South African gold mines or lived in associated labor-sending communities. We simulated the implementation of a postinfection adult vaccine with 60% efficacy and a mean effect duration of 10 years. We then compared the impact of a mine-targeted vaccination strategy, in which miners were vaccinated while in the mines, with that of a community-targeted strategy, in which random individuals within the labor-sending communities were vaccinated. Mine-targeted vaccination averted an estimated 0.37 TB cases per vaccine dose compared with 0.25 for community-targeted vaccination, for a relative efficacy of 1.46 (95% range, 1.13-1.91). The added benefit of mine-targeted vaccination primarily reflected the disproportionate demographic burden of TB among the population of adult males as a whole. As novel vaccines for TB are developed, venue-based vaccine delivery that targets high-risk demographic groups may improve both vaccine feasibility and the impact on transmission., (© The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The Xpert MTB/RIF (Xpert) assay offers rapid and accurate diagnosis of tuberculosis (TB) but still suffers from imperfect sensitivity. The newer Xpert MTB/RIF Ultra cartridge has shown improved sensitivity in recent field trials, but at the expense of reduced specificity. The clinical implications of switching from the existing Xpert cartridge to the Xpert Ultra cartridge in different populations remain uncertain., Methods and Findings: We developed a Markov microsimulation model of hypothetical cohorts of 100,000 individuals undergoing diagnostic sputum evaluation with Xpert for suspected pulmonary TB, in each of 3 emblematic settings: an HIV clinic in South Africa, a public TB center in India, and an adult primary care setting in China. In each setting, we used existing data to project likely diagnostic results, treatment decisions, and ultimate clinical outcomes, assuming use of the standard Xpert versus Xpert Ultra cartridge. Our primary outcomes were the projected number of additional unnecessary treatments generated, the projected number of TB deaths averted, and the projected number of unnecessary treatments generated per TB death averted, if standard Xpert were switched to Xpert Ultra. We also simulated alternative approaches to interpreting positive results of the Ultra cartridge's semi-quantitative trace call. Extensive sensitivity and uncertainty analyses were performed to evaluate the drivers and generalizability of projected results. In the Indian TB center setting, replacing the standard Xpert cartridge with the Xpert Ultra cartridge was projected to avert 0.5 TB deaths (95% uncertainty range [UR]: 0, 1.3) and generate 18 unnecessary treatments (95% UR: 10, 29) per 1,000 individuals evaluated-resulting in a median ratio of 38 incremental unnecessary treatments added by Ultra per incremental death averted by Ultra compared to outcomes using standard Xpert (95% UR: 12, indefinite upper bound). In the South African HIV care setting-where TB mortality rates are higher and Ultra's improved sensitivity has greater absolute benefit-this ratio improved to 7 unnecessary treatments per TB death averted (95% UR: 2, 43). By contrast, in the Chinese primary care setting, this ratio was much less favorable, at 372 unnecessary treatments per TB death averted (95% UR: 75, indefinite upper bound), although the projected number of unnecessary treatments using Xpert Ultra was lower (with a possibility of no increased overtreatment) when using specificity data only from lower-burden settings. Alternative interpretations of the trace call had little effect on these ratios. Limitations include uncertainty in key parameters (including the clinical implications of false-negative results), the exclusion of transmission effects, and restriction of this analysis to adult pulmonary TB., Conclusions: Switching from the standard Xpert cartridge to the Xpert Ultra cartridge for diagnosis of adult pulmonary TB may have different consequences in different clinical settings. In settings with high TB and HIV prevalence, Xpert Ultra is likely to offer considerable mortality benefit, whereas in lower-prevalence settings, Xpert Ultra will likely result in considerable overtreatment unless the possibility of higher specificity of Ultra in lower-prevalence settings in confirmed. The ideal use of the Ultra cartridge may therefore involve a more nuanced, setting-specific approach to implementation, with priority given to populations in which the anticipated prevalence of TB (and HIV) is the highest.

Background: Symptom-based screening for tuberculosis is recommended for all people living with HIV. This recommendation results in unnecessary Xpert MTB/RIF testing in many individuals living in tuberculosis-endemic areas and thus poor implementation of intensified case finding and tuberculosis preventive therapy. Novel approaches to tuberculosis screening are needed to help achieve global targets for tuberculosis elimination. We assessed the performance of C-reactive protein (CRP) measured with a point-of-care assay as a screening tool for active pulmonary tuberculosis., Methods: For this prospective study, we enrolled adults (aged ≥18 years) living with HIV with CD4 cell count less than or equal to 350 cells per μL who were initiating antiretroviral therapy (ART) from two HIV/AIDS clinics in Uganda. CRP concentrations were measured at study entry with a point-of-care assay using whole blood obtained by fingerprick (concentration ≥10 mg/L defined as screen positive for tuberculosis). Sputum samples were collected for Xpert MTB/RIF testing and culture. We calculated the sensitivity and specificity of point-of-care CRP and WHO symptom-based screening in reference to culture results. We repeated the sensitivity analysis with Xpert MTB/RIF as the reference standard., Findings: Between July 8, 2013, and Dec 15, 2015, 1237 HIV-infected adults were enrolled and underwent point-of-care CRP testing. 60 (5%) patients with incomplete or contaminated cultures were excluded from the analysis. Of the remaining 1177 patients (median CD4 count 165 cells per μL [IQR 75-271]), 163 (14%) had culture-confirmed tuberculosis. Point-of-care CRP testing had 89% sensitivity (145 of 163, 95% CI 83-93) and 72% specificity (731 of 1014, 95% CI 69-75) for culture-confirmed tuberculosis. Compared with WHO symptom-based screening, point-of-care CRP testing had lower sensitivity (difference -7%, 95% CI -12 to -2; p=0·002) but substantially higher specificity (difference 58%, 95% CI 55 to 61; p<0·0001). When Xpert MTB/RIF results were used as the reference standard, sensitivity of point-of-care CRP and WHO symptom-based screening were similar (94% [79 of 84] vs 99% [83 of 84], respectively; difference -5%, 95% CI -12 to 2; p=0·10)., Interpretation: The performance characteristics of CRP support its use as a tuberculosis screening test for people living with HIV with CD4 count less than or equal to 350 cells per μL who are initiating ART. HIV/AIDS programmes should consider point-of-care CRP-based tuberculosis screening to improve the efficiency of intensified case finding and increase uptake of tuberculosis preventive therapy., Funding: National Institutes of Health; President's Emergency Plan for AIDS Relief; University of California, San Francisco, Nina Ireland Program for Lung Health., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this Perspective on the research article by William Rudgard and colleagues, Priya Shete and coauthor discuss the challenges of measuring the impact of social protection programs such as cash transfers.

High rates of tuberculosis transmission are driving the ongoing global tuberculosis epidemic, and there is a pressing need for research focused on understanding and, ultimately, halting transmission. The ongoing tuberculosis-human immunodeficiency virus (HIV) coepidemic and rising rates of drug-resistant tuberculosis in parts of the world add further urgency to this work. Success in this research will require a concerted, multidisciplinary effort on the part of tuberculosis scientists, clinicians, programs, and funders and must span the research spectrum from biomedical sciences to the social sciences, public health, epidemiology, cost-effectiveness analyses, and operations research. Heterogeneity of tuberculosis disease, both among individual patients and among communities, poses a substantial challenge to efforts to interrupt transmission. As such, it is likely that effective interventions to stop transmission will require a combination of approaches that will vary across different epidemiologic settings. This research roadmap summarizes key gaps in our current understanding of transmission, as laid out in the preceding articles in this series. We also hope that it will be a call to action for the global tuberculosis community to make a sustained commitment to tuberculosis transmission science. Halting transmission today is an essential step on the path to end tuberculosis tomorrow., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.)

To reduce the incidence of tuberculosis, it is insufficient to simply understand the dynamics of tuberculosis transmission. Rather, we must design and rigorously evaluate interventions to halt transmission, prioritizing those interventions most likely to achieve population-level impact. Synergy in reducing tuberculosis transmission may be attainable by combining interventions that shrink the reservoir of latent Mycobacterium tuberculosis infection (preventive therapy), shorten the time between disease onset and treatment initiation (case finding and diagnosis), and prevent transmission in key settings, such as the built environment (infection control). In evaluating efficacy and estimating population-level impact, cluster-randomized trials and mechanistic models play particularly prominent roles. Historical and contemporary evidence suggests that effective public health interventions can halt tuberculosis transmission, but an evidence-based approach based on knowledge of local epidemiology is necessary for success. We provide a roadmap for designing, evaluating, and modeling interventions to interrupt the process of transmission that fuels a diverse array of tuberculosis epidemics worldwide., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.)

Rationale: There is substantial state-to-state heterogeneity in tuberculosis (TB) in the United States; better understanding this heterogeneity can inform effective response to TB at the state level, the level at which most TB control efforts are coordinated., Objectives: To characterize drivers of state-level heterogeneity in TB epidemiology in the four U.S. states that bear half the country's TB burden: California, Florida, New York, and Texas., Methods: We constructed an individual-based model of TB in the four U.S. states and calibrated the model to state-specific demographic and age- and nativity-stratified TB incidence data. We used the model to infer differences in natural history of TB and in future projections of TB., Measurements and Main Results: We found that differences in both demographic makeup (particularly the size and composition of the foreign-born population) and TB transmission dynamics contribute to state-level differences in TB epidemiology. The projected median annual rate of decline in TB incidence in the next decade was substantially higher in Texas (3.3%; 95% range, -5.6 to 10.9) than in California (1.7%; 95% range, -3.8 to 7.1), Florida (1.5%; 95% range, -7.4 to 14), and New York (1.9%; 95% range, -6.4 to 9.8). All scenarios projected a flattening of the decline in TB incidence by 2025 without additional resources or interventions., Conclusions: There is substantial state-level heterogeneity in TB epidemiology in the four states, which reflect both demographic factors and potential differences in the natural history of TB. These differences may inform resource allocation decisions in these states.

A novel, shorter-course regimen for treating multidrug-resistant (MDR) tuberculosis was recently recommended by the World Health Organization. However, the most appropriate use of drug susceptibility testing (DST) to support this regimen is less clear. Implementing countries must therefore often choose between using a standardized regimen despite high levels of underlying drug resistance or require more stringent DST prior to treatment initiation. The former carries a high likelihood of exposing patients to de facto monotherapy with a critical drug class (fluoroquinolones), whereas the latter could exclude large groups of patients from their most effective treatment option. We discuss the implications of this dilemma and argue for an approach that will integrate DST into the delivery of any novel antimicrobial regimen, without excessively stringent requirements. Such guidance could make the novel MDR tuberculosis regimen available to most patients while reducing the risk of generating additional drug resistance.

Introduction: Despite the close link between tuberculosis (TB) and poverty, most mathematical models of TB have not addressed underlying social and structural determinants., Objective: To review studies employing mathematical modelling to evaluate the epidemiological impact of the structural determinants of TB., Methods: We systematically searched PubMed and personal libraries to identify eligible articles. We extracted data on the modelling techniques employed, research question, types of structural determinants modelled and setting., Results: From 232 records identified, we included eight articles published between 2008 and 2015; six employed population-based dynamic TB transmission models and two non-dynamic analytic models. Seven studies focused on proximal TB determinants (four on nutritional status, one on wealth, one on indoor air pollution, and one examined overcrowding, socio-economic and nutritional status), and one focused on macro-economic influences., Conclusions: Few modelling studies have attempted to evaluate structural determinants of TB, resulting in key knowledge gaps. Despite the challenges of modelling such a complex system, models must broaden their scope to remain useful for policy making. Given the intersectoral nature of the interrelations between structural determinants and TB outcomes, this work will require multidisciplinary collaborations. A useful starting point would be to focus on developing relatively simple models that can strengthen our knowledge regarding the potential effect of the structural determinants on TB outcomes.

Objective: Determine the effectiveness of strategies to increase linkage to care after testing HIV positive at mobile HIV testing in South Africa., Design: Unmasked randomized controlled trial., Methods: Recruitment of adults testing HIV positive and not currently in HIV care occurred at 7 mobile HIV counseling and testing units in urban, periurban, and rural South Africa with those consenting randomized 1:1:1:1 into 1 of 4 arms. Three strategies were compared with standard of care (SOC): point-of-care CD4 count testing (POC CD4), POC CD4 plus longitudinal strengths-based counseling (care facilitation; CF), and POC CD4 plus transport reimbursement (transport). Participants were followed up telephonically and through clinic records and analyzed with an intention-to-treat analysis., Results: From March 2013 to October 2014, 2558 participants were enrolled, of whom 160 were excluded postrandomization. Compared with the SOC arm where 298 (50%) reported having entered care, linkage to care was 319 (52%) for POC CD4, hazard ratio (HR) 1.0 [95% confidence interval (CI): 0.89 to 1.2, P = 0.6]; 331 (55%) for CF, HR: 1.1 (95% CI: 0.84 to 1.3, P = 0.2); and 291 (49%) for transport, HR 0.97 (95% CI: 0.83 to 1.1, P = 0.7). Linkage to care verified with clinical records that occurred for 172 (29%) in the SOC arm; 187 (31%) in the POC CD4 arm, HR: 1.0 (95% CI: 0.86 to 1.3, P = 0.6); 225 (38%) in the CF arm, HR: 1.4 (95% CI: 1.1 to 1.7, P = 0.001); and 180 (31%) in the transport arm, HR: 1.1 (95% CI: 0.88 to 1.3, P = 0.5)., Conclusions: CF improved verified linkage to care from 29% to 38%.

Background: Mathematical models are increasingly used to understand the dynamics of infectious diseases, including "chronic" infections with long generation times. Such models include features that are obscure to most clinicians and decision-makers., Methods: Using a model of a hypothetical active case-finding intervention for tuberculosis in India as an example, we illustrate the effects on model results of different choices for model structure, input parameters, and calibration process., Results: Using the same underlying data, different transmission models produced different estimates of the projected intervention impact on tuberculosis incidence by 2030 with different corresponding uncertainty ranges. We illustrate the reasons for these differences and present a simple guide for clinicians and decision-makers to evaluate models of infectious diseases., Conclusions: Mathematical models of chronic infectious diseases must be understood to properly inform policy decisions. Improved communication between modelers and consumers is critical if model results are to improve the health of populations.

Introduction: Numerous micronutrients have immunomodulatory roles that may influence risk of tuberculosis (TB), but the association between baseline micronutrient deficiencies and incident TB after antiretroviral therapy (ART) initiation in HIV-infected individuals is not well characterized., Methods: We conducted a case-cohort study (n = 332) within a randomized trial comparing 3 ART regimens in 1571 HIV treatment-naive adults from 9 countries. A subcohort of 30 patients was randomly selected from each country (n = 270). Cases (n = 77; main cohort = 62, random subcohort = 15) included patients diagnosed with TB by 96 weeks post-ART initiation. We determined pretreatment concentrations of vitamin A, carotenoids, vitamin B6, vitamin B12, vitamin D, vitamin E, and selenium. We measured associations between pretreatment micronutrient deficiencies and incident TB using Breslow-weighted Cox regression models., Results: Median pretreatment CD4 T-cell count was 170 cells/mm; 47.3% were women; and 53.6% Black. In multivariable models after adjusting for age, sex, country, treatment arm, previous TB, baseline CD4 count, HIV viral load, body mass index, and C-reactive protein, pretreatment deficiency in vitamin A (adjusted hazard ratio, aHR 5.33, 95% confidence interval, CI: 1.54 to 18.43) and vitamin D (aHR 3.66, 95% CI: 1.16 to 11.51) were associated with TB post-ART., Conclusions: In a diverse cohort of HIV-infected adults from predominantly low- and middle-income countries, deficiencies in vitamin A and vitamin D at ART initiation were independently associated with increased risk of incident TB in the ensuing 96 weeks. Vitamin A and D may be important modifiable risk factors for TB in high-risk HIV-infected patients starting ART in resource-limited highly-TB-endemic settings.

Background: After steady decline since the 1990s, tuberculosis (TB) incidence in New York City (NYC) and the United States (US) has flattened. The reasons for this trend and the implications for the future trajectory of TB in the US remain unclear., Methods: We developed a compartmental model of TB in NYC, parameterized with detailed epidemiological data. We ran the model under five alternative scenarios representing different explanations for recent declines in TB incidence. We evaluated each scenario's relative likelihood by comparing its output to available data. We used the most likely scenarios to explore drivers of TB incidence and predict future trajectories of the TB epidemic in NYC., Findings: Demographic changes and declining TB transmission alone were insufficient to explain recent trends in NYC TB incidence. Only scenarios that assumed contemporary changes in TB dynamics among the foreign-born - a declining rate of reactivation or a decrease in imported subclinical TB - could accurately describe the trajectory of TB incidence since 2007. In those scenarios, the projected decline in TB incidence from 2015 to 2025 varied from minimal [2·0%/year (95% credible interval 0·4-3·5%)] to similar to 2005 to 2009 trends [4·4%/year (2·5-6·4%)]. The primary factor differentiating optimistic from pessimistic projections was the degree to which improvements in TB dynamics among the foreign-born continued into the coming decade., Interpretation: Further progress against TB in NYC requires additional focus on the foreign-born population. Absent additional intervention in this group, TB incidence may not decline further., Competing Interests: CONFLICTS OF INTEREST: None

Objectives: Preexposure prophylaxis (PrEP) is recommended for preventing HIV infection among individuals at high risk, including men who have sex with men (MSM). Although its individual-level efficacy is proven, questions remain regarding population-level impact of PrEP implementation., Design: We developed an agent-based simulation of HIV transmission among MSM, accounting for demographics, sexual contact network, HIV disease stage, and use of antiretroviral therapy. We use this framework to compare PrEP delivery strategies in terms of impact on HIV incidence and prevalence., Results: The projected reduction in HIV incidence achievable with PrEP reflects both population-level coverage and individual-level adherence (as a proportion of days protected against HIV transmission). For example, provision of PrEP to 40% of HIV-negative MSM reporting more than one sexual partner in the last 12 months, taken with sufficient adherence to provide protection on 40% of days, can reduce HIV incidence by 9.5% (95% uncertainty range: 8%-11%) within 5 years. However, if this could be increased to 80% coverage on 80% of days (eg, through mass campaigns with a long-acting injectable formulation), a 43% (42%-44%) reduction in HIV incidence could be achieved. Delivering PrEP to MSM at high risk for HIV acquisition can augment population-level impact up to 1.8-fold., Conclusions: If highly ambitious targets for coverage and adherence can be achieved, PrEP can substantially reduce HIV incidence in the short-term. Although the reduction in HIV incidence largely reflects the proportion of person-years protected, the efficiency of PrEP delivery can be enhanced by targeting high-risk populations.

Background: In 2013, approximately 480,000 people developed active multidrug-resistant tuberculosis (MDR-TB), while only 97,000 started MDR-TB treatment. We sought to estimate the impact of improving access to MDR-TB diagnosis and treatment, under multiple diagnostic algorithm and treatment regimen scenarios, on ten-year projections of MDR-TB incidence and mortality., Methods: We constructed a dynamic transmission model of an MDR-TB epidemic in an illustrative East/Southeast Asian setting. Using approximate Bayesian computation, we investigated a wide array of potential epidemic trajectories consistent with current notification data and known TB epidemiology., Results: Despite an overall projected decline in TB incidence, data-consistent simulations suggested that MDR-TB incidence is likely to rise between 2015 and 2025 under continued 2013 treatment practices, although with considerable uncertainty (median 17% increase, 95% Uncertainty Range [UR] -38% to +137%). But if, by 2017, all identified active TB patients with previously-treated TB could be tested for drug susceptibility, and 85% of those with MDR-TB could initiate MDR-appropriate treatment, then MDR-TB incidence in 2025 could be reduced by 26% (95% UR 4-52%) relative to projections under continued current practice. Also expanding this drug-susceptibility testing and appropriate MDR-TB treatment to treatment-naïve as well as previously-treated TB cases, by 2020, could reduce MDR-TB incidence in 2025 by 29% (95% UR 6-55%) compared to continued current practice. If this diagnosis and treatment of all MDR-TB in known active TB cases by 2020 could be implemented via a novel second-line regimen with similar effectiveness and tolerability as current first-line therapy, a 54% (95% UR 20-74%) reduction in MDR-TB incidence compared to current-practice projections could be achieved by 2025., Conclusions: Expansion of diagnosis and treatment of MDR-TB, even using current sub-optimal second-line regimens, is expected to significantly decrease MDR-TB incidence at the population level. Focusing MDR diagnostic efforts on previously-treated cases is an efficient first-step approach.

Treatment failure and resistance amplification are common among patients with rifampin-resistant tuberculosis (TB). Drug susceptibility testing (DST) for second-line drugs is recommended for these patients, but logistical difficulties have impeded widespread implementation of second-line DST in many settings. To provide a quantitative perspective on the decision to scale up second-line DST, we synthesize literature on the prevalence of second-line drug resistance, the expected clinical and epidemiologic benefits of using second-line DST to ensure that patients with rifampin-resistant TB receive effective regimens, and the costs of implementing (or not implementing) second-line DST for all individuals diagnosed with rifampin-resistant TB. We conclude that, in most settings, second-line DST could substantially improve treatment outcomes for patients with rifampin-resistant TB, reduce transmission of drug-resistant TB, prevent amplification of drug resistance, and be affordable or even cost-saving. Given the large investment made in each patient treated for rifampin-resistant TB, these payoffs would come at relatively small incremental cost. These anticipated benefits likely justify addressing the real challenges faced in implementing second-line DST in most high-burden settings., (Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: In May, 2016, WHO endorsed a 9 month regimen for multidrug-resistant tuberculosis that is cheaper and potentially more effective than the conventional, longer (20-24 month) therapy. We aimed to investigate the population-level implications of scaling up this new regimen., Methods: In this population modelling analysis, we developed a dynamic transmission model to simulate the introduction of this short-course regimen as an instantaneous switch in 2016. We projected the corresponding percentage reduction in the incidence of multidrug-resistant tuberculosis by 2024 compared with continued use of longer therapy. In the primary analysis in a representative southeast Asian setting, we assumed that the short-course regimen would double treatment access (through savings in resources or capacity) and achieve long-term efficacy at levels seen in preliminary cohort studies. We then did extensive sensitivity analyses to explore a range of alternative scenarios., Findings: Under the optimistic assumptions in the primary analysis, the incidence of multidrug-resistant tuberculosis in 2024 would be 3·3 (95% uncertainty range 2·2-5·6) per 100 000 population with the short-course regimen and 4·3 (2·9-7·6) per 100 000 population with continued use of longer therapy-ie, the short-course regimen could reduce incidence by 23% (10-38). Incidence would be reduced by 14% (4-28) if the new regimen affected only treatment effectiveness and by 11% (3-24) if it affected only treatment availability. Under more pessimistic assumptions, the short-course regimen would have minimal effect and even potential for harm-eg, when 30% of patients are ineligible for the new regimen because of second-line drug resistance, we projected a change in incidence of -2% (-20 to +28). The new regimen's effect was greater in settings with more ongoing transmission of multidrug-resistant tuberculosis, but results were otherwise similar across settings with different levels of tuberculosis incidence and prevalence of multidrug resistance., Interpretation: The short-course regimen has potential to substantially lessen the multidrug-resistant tuberculosis epidemic, but this effect depends on its long-term efficacy, its ability to expand treatment access, and the role of second-line drug resistance., Funding: US National Institutes of Health and Bill & Melinda Gates Foundation., (Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license. Published by Elsevier Ltd.. All rights reserved.)

Several infectious diseases of global importance-e.g., HIV infection and tuberculosis (TB)-require prolonged treatment with combination antimicrobial regimens typically involving high-potency core agents coupled with additional companion drugs that protect against the de novo emergence of mutations conferring resistance to the core agents. Often, the most effective (or least toxic) companion agents are reused in sequential (first-line, second-line, etc.) regimens. We used a multistrain model of Mycobacterium tuberculosis transmission in Southeast Asia to investigate how this practice might facilitate the emergence of extensive drug resistance, i.e., resistance to multiple core agents. We calibrated this model to regional TB and drug resistance data using an approximate Bayesian computational approach. We report the proportion of data-consistent simulations in which the prevalence of pre-extensively drug-resistant (pre-XDR) TB-defined as resistance to both first-line and second-line core agents (rifampin and fluoroquinolones)-exceeds predefined acceptability thresholds (1 to 2 cases per 100,000 population by 2035). The use of pyrazinamide (the most effective companion agent) in both first-line and second-line regimens increased the proportion of simulations in which the prevalence exceeded the pre-XDR acceptability threshold by 7-fold compared to a scenario in which patients with pyrazinamide-resistant TB received an alternative drug. Model parameters related to the emergence and transmission of pyrazinamide-resistant TB and resistance amplification were among those that were the most strongly correlated with the projected pre-XDR prevalence, indicating that pyrazinamide resistance acquired during first-line treatment subsequently promotes amplification to pre-XDR TB under pyrazinamide-containing second-line treatment. These findings suggest that the appropriate use of companion drugs may be critical to preventing the emergence of strains resistant to multiple core agents., (Copyright © 2017 Fofana et al.)

Background: Novel drug regimens are needed for tuberculosis (TB) treatment. New regimens aim to improve on characteristics such as duration, efficacy, and safety profile, but no single regimen is likely to be ideal in all respects. By linking these regimen characteristics to a novel regimen's ability to reduce TB incidence and mortality, we sought to prioritize regimen characteristics from a population-level perspective., Methods and Findings: We developed a dynamic transmission model of multi-strain TB epidemics in hypothetical populations reflective of the epidemiological situations in India (primary analysis), South Africa, the Philippines, and Brazil. We modeled the introduction of various novel rifampicin-susceptible (RS) or rifampicin-resistant (RR) TB regimens that differed on six characteristics, identified in consultation with a team of global experts: (1) efficacy, (2) duration, (3) ease of adherence, (4) medical contraindications, (5) barrier to resistance, and (6) baseline prevalence of resistance to the novel regimen. We compared scale-up of these regimens to a baseline reflective of continued standard of care. For our primary analysis situated in India, our model generated baseline TB incidence and mortality of 157 (95% uncertainty range [UR]: 113-187) and 16 (95% UR: 9-23) per 100,000 per year at the time of novel regimen introduction and RR TB incidence and mortality of 6 (95% UR: 4-10) and 0.6 (95% UR: 0.3-1.1) per 100,000 per year. An optimal RS TB regimen was projected to reduce 10-y TB incidence and mortality in the India-like scenario by 12% (95% UR: 6%-20%) and 11% (95% UR: 6%-20%), respectively, compared to current-care projections. An optimal RR TB regimen reduced RR TB incidence by an estimated 32% (95% UR: 18%-46%) and RR TB mortality by 30% (95% UR: 18%-44%). Efficacy was the greatest determinant of impact; compared to a novel regimen meeting all minimal targets only, increasing RS TB treatment efficacy from 94% to 99% reduced TB mortality by 6% (95% UR: 1%-13%, half the impact of a fully optimized regimen), and increasing the efficacy against RR TB from 76% to 94% lowered RR TB mortality by 13% (95% UR: 6%-23%). Reducing treatment duration or improving ease of adherence had smaller but still substantial impact: shortening RS TB treatment duration from 6 to 2 mo lowered TB mortality by 3% (95% UR: 1%-6%), and shortening RR TB treatment from 20 to 6 mo reduced RR TB mortality by 8% (95% UR: 4%-13%), while reducing nonadherence to the corresponding regimens by 50% reduced TB and RR TB mortality by 2% (95% UR: 1%-4%) and 6% (95% UR: 3%-10%), respectively. Limitations include sparse data on key model parameters and necessary simplifications to model structure and outcomes., Conclusions: In designing clinical trials of novel TB regimens, investigators should consider that even small changes in treatment efficacy may have considerable impact on TB-related incidence and mortality. Other regimen improvements may still have important benefits for resource allocation and outcomes such as patient quality of life., Competing Interests: This work was supported by the National Institutes of Health 5T32-AI007291-25 (www.nih.gov) and by the Bill and Melinda Gates Foundation work order 10 (www.gatesfoundation.org). The NIH had no role in study design, data collection and analysis, or decision to publish. TF and CB are employees of the Bill and Melinda Gates Foundation and contributed as coauthors to framing of the study and review of the manuscript prior to publication; TF and CB did not have any role in the decision to fund this grant.