Experience With Four-Month Rifapentine and Moxifloxacin-Based Tuberculosis Treatment in San Francisco

Background

A multicountry randomized controlled trial has demonstrated that pan-susceptible pulmonary tuberculosis (TB) can be successfully treated with a 4-month regimen of daily isoniazid, rifapentine, moxifloxacin, and pyrazinamide (HPMZ). We piloted HPMZ in San Francisco (SF) using a modified version of the US Centers for Disease Control and Prevention HPMZ treatment guidelines.

Methods

In this retrospective cohort, patients consecutively referred to SF TB clinic were evaluated for HPMZ eligibility based on preestablished inclusion/exclusion criteria. All underwent evaluation and management according to national recommendations. We reviewed the medical records of those initiated on HPMZ.

Results

From August 2021 to December 2023, 30 (18.8%) of 160 patients diagnosed with active TB met HPMZ inclusion criteria; of these, 22 (13.8%) started HPMZ. The median age (range) was 32.5 (14-86) years, 17 (77.3%) were otherwise healthy, and 19 (86.4%) had pulmonary TB, including 7 (36.8%) with cavitary disease. Eighteen (81.8%) patients had an adverse event, with 11 (50%) prematurely discontinuing HPMZ; the most common adverse events were vomiting, elevated transaminases, and rash. To date, 9 (40.9%) have completed treatment, with most achieving criteria for cure. One patient was diagnosed with possible TB recurrence and restarted standard TB treatment.

Conclusions

Our experience, with half of patients to date prematurely discontinuing HPMZ, illustrates the challenge of extrapolating findings from TB clinical trials commonly conducted in high-incidence, non-US settings to US clinical practice. Further experience may help identify best practices for implementing HPMZ, including identifying predictors of which patients may be most likely to benefit from and tolerate this regimen.

Pharmacokinetic-Pharmacodynamic Evidence from a Phase 3 Trial to Support Flat-Dosing of Rifampicin for Tuberculosis

BACKGROUND

The optimal dosing strategy for rifampicin in treating drug-susceptible tuberculosis (TB) is still highly debated. In the Phase 3 clinical trial Study 31/ACTG 5349 (NCT02410772), all participants in the control regimen arm received 600 mg rifampicin daily as a flat dose. Here, we evaluated relationships between rifampicin exposure and efficacy and safety outcomes.

METHODS

We analyzed rifampicin concentration time profiles using population nonlinear mixed-effects models. We compared simulated rifampicin exposure from flat- and weight-banded dosing. We evaluated the effect of rifampicin exposure on stable culture conversion at 6 months, TB-related unfavorable outcomes at 9, 12, and 18 months using Cox proportional hazard models, and all trial-defined safety outcomes using logistic regression.

RESULTS

Our model derived rifampicin exposure ranged from 4.57 mg·h/L to 140.0 mg·h/L with a median of 41.8 mg·h/L. Pharmacokinetic simulations demonstrated that flat-dosed rifampicin provided exposure coverage similar to weight-banded dose. Exposure-efficacy analysis (N=680) showed that participants with rifampicin exposure below the median experienced similar hazards of stable culture conversion and TB-related unfavorable outcomes compared to those with exposure above the median. Exposure-safety analysis (N=722) showed that increased rifampicin exposure was not associated with increased grade 3 or higher adverse events, or serious adverse events.

CONCLUSIONS

Flat-dosing of rifampicin at 600 mg daily may be a reasonable alternative to the incumbent weight-banded dosing strategy for the standard of care 6-month regimen. Future research should assess the optimal dosing strategy for rifampicin, at doses higher than the current recommendation.

Standards for clinical trials for treating TB

BACKGROUND: The value, speed of completion and robustness of the evidence generated by TB treatment trials could be improved by implementing standards for best practice.METHODS: A global panel of experts participated in a Delphi process, using a 7-point Likert scale to score and revise draft standards until consensus was reached.RESULTS: Eleven standards were defined: Standard 1, high quality data on TB regimens are essential to inform clinical and programmatic management; Standard 2, the research questions addressed by TB trials should be relevant to affected communities, who should be included in all trial stages; Standard 3, trials should make every effort to be as inclusive as possible; Standard 4, the most efficient trial designs should be considered to improve the evidence base as quickly and cost effectively as possible, without compromising quality; Standard 5, trial governance should be in line with accepted good clinical practice; Standard 6, trials should investigate and report strategies that promote optimal engagement in care; Standard 7, where possible, TB trials should include pharmacokinetic and pharmacodynamic components; Standard 8, outcomes should include frequency of disease recurrence and post-treatment sequelae; Standard 9, TB trials should aim to harmonise key outcomes and data structures across studies; Standard 10, TB trials should include biobanking; Standard 11, treatment trials should invest in capacity strengthening of local trial and TB programme staff.CONCLUSION: These standards should improve the efficiency and effectiveness of evidence generation, as well as the translation of research into policy and practice.

Evaluating newly approved drugs in combination regimens for multidrug-resistant tuberculosis with fluoroquinolone resistance (endTB-Q): study protocol for a multi-country randomized controlled trial

BACKGROUND

Treatment for fluoroquinolone-resistant multidrug-resistant/rifampicin-resistant tuberculosis (pre-XDR TB) often lasts longer than treatment for less resistant strains, yields worse efficacy results, and causes substantial toxicity. The newer anti-tuberculosis drugs, bedaquiline and delamanid, and repurposed drugs clofazimine and linezolid, show great promise for combination in shorter, less-toxic, and effective regimens. To date, there has been no randomized, internally and concurrently controlled trial of a shorter, all-oral regimen comprising these newer and repurposed drugs sufficiently powered to produce results for pre-XDR TB patients.

METHODS

endTB-Q is a phase III, multi-country, randomized, controlled, parallel, open-label clinical trial evaluating the efficacy and safety of a treatment strategy for patients with pre-XDR TB. Study participants are randomized 2:1 to experimental or control arms, respectively. The experimental arm contains bedaquiline, linezolid, clofazimine, and delamanid. The control comprises the contemporaneous WHO standard of care for pre-XDR TB. Experimental arm duration is determined by a composite of smear microscopy and chest radiographic imaging at baseline and re-evaluated at 6 months using sputum culture results: participants with less extensive disease receive 6 months and participants with more extensive disease receive 9 months of treatment. Randomization is stratified by country and by participant extent-of-TB-disease phenotype defined according to screening/baseline characteristics. Study participation lasts up to 104 weeks post randomization. The primary objective is to assess whether the efficacy of experimental regimens at 73 weeks is non-inferior to that of the control. A sample size of 324 participants across 2 arms affords at least 80% power to show the non-inferiority, with a one-sided alpha of 0.025 and a non-inferiority margin of 12%, against the control in both modified intention-to-treat and per-protocol populations.

DISCUSSION

This internally controlled study of shortened treatment for pre-XDR TB will provide urgently needed data and evidence for clinical and policy decision-making around the treatment of pre-XDR TB with a four-drug, all-oral, shortened regimen.

TRIAL REGISTRATION

ClinicalTrials.Gov NCT03896685. Registered on 1 April 2018; the record was last updated for study protocol version 4.3 on 17 March 2023.

Recent advances in the treatment of tuberculosis

BACKGROUND

Tuberculosis (TB) is a global health challenge and one of the leading causes of death worldwide. In the last decade, the TB treatment landscape has dramatically changed. After long years of stagnation, new compounds entered the market (bedaquiline, delamanid, and pretomanid) and phase III clinical trials have shown promising results towards shortening duration of treatment for both drug-susceptible (Study 31/A5349, TRUNCATE-TB, and SHINE) and drug-resistant TB (STREAM, NiX-TB, ZeNix, and TB-PRACTECAL). Dose optimization of rifamycins and repurposed drugs has also brought hopes of further development of safe and effective regimens. Consequently, international and WHO clinical guidelines have been updated multiple times in the last years to keep pace with these advances.

OBJECTIVES

This narrative review aims to summarize the state-of-the-art on treatment of drug-susceptible and drug-resistant TB, as well as recent trial results and an overview of ongoing clinical trials.

SOURCES

A non-systematic literature review was conducted in PubMed and MEDLINE, focusing on the treatment of TB. Ongoing clinical trials were listed according to the authors' knowledge and completed consulting clinicaltrials.gov and other publicly available websites (www.resisttb.org/clinical-trials-progress-report, www.newtbdrugs.org/pipeline/trials).

CONTENT

This review summarizes the recent, major changes in the landscape for drug-susceptible and drug-resistant treatment, with a specific focus on their potential impact on patient outcomes and programmatic TB management. Moreover, insights in host-directed therapies, and advances in pharmacokinetics and pharmacogenomics are discussed. A thorough outline of ongoing therapeutic clinical trials is presented, highlighting different approaches and goals in current TB clinical research.

IMPLICATIONS

Future research should be directed to individualize regimens and protect these recent breakthroughs by preventing and identifying the selection of drug resistance and providing widespread, affordable, patient-centred access to new treatment options for all people affected by TB.

Respiratory, Cardiac, and Neuropsychiatric Manifestations of Postacute Sequelae of Coronavirus Disease 2019 in Lima, Peru

Background

Few studies have examined the burden of postacute sequelae of coronavirus disease 2019 (COVID-19) (PASC) in low- and middle-income countries. We sought to characterize PASC with self-reported questionnaires and clinical examinations of end-organ function in Lima, Peru.

Methods

From January to July 2021, we recruited participants at least 8 weeks after COVID-19 diagnosis from a case registry in Lima, Peru. We evaluated participants for PASC with questionnaires, neuropsychiatric evaluations, chest X-ray, spirometry, electrocardiogram, and echocardiogram. We used multivariable models to identify risk factors for PASC.

Results

We assessed 989 participants for PASC at a median 4.7 months after diagnosis. Clinically significant respiratory symptoms were reported by 68.3% of participants, particularly those who had been severely ill during acute COVID-19, and were associated with cardiac findings of ventricular hypertrophy or dilation on echocardiogram. Neuropsychiatric questionnaires were consistent with depression in 20.7% and cognitive impairment in 8.0%. Female sex and older age were associated with increased risk of respiratory (adjusted odds ratio [aOR], 2.36 [95% confidence interval {CI}, 1.69-3.31] and aOR, 1.01 [95% CI, 1.00-1.03], respectively) and neuropsychiatric sequelae (aOR, 2.99 [95% CI, 2.16-4.18] and aOR, 1.02 [95% CI, 1.01-1.03], respectively).

Conclusions

COVID-19 survivors in Lima, Peru, experienced frequent postacute respiratory symptoms and depression, particularly among older and female participants. Clinical examinations highlighted the need for cardiopulmonary rehabilitation among persons with severe COVID-19; psychosocial support may be required among all COVID-19 survivors.

Clinical Outcomes of Individuals with COVID-19 and Tuberculosis during the Pre-Vaccination Period of the Pandemic: A Systematic Review

Background: Tuberculosis, like COVID-19, is most often a pulmonary disease. The COVID-19 pandemic has severely disrupted tuberculosis services in myriad ways: health facility closures, lockdowns, travel bans, overwhelmed healthcare systems, restricted export of antituberculous drugs, etc. The effects of the shared risk on outcomes of the two diseases is not known, particularly for the first year of the pandemic, during the period before COVID-19 vaccines became widely available. Objective: We embarked on a systematic review to elucidate the consequences of tuberculosis on COVID-19 outcomes and of COVID-19 on tuberculosis outcomes during the pre-vaccination period of the pandemic. Methods: The systematic review protocol is registered in PROSPERO. We conducted an initial search of PubMed, Embase, Web of Science, WHO coronavirus database, medRxiv, bioRxiv, preprints.org, and Google Scholar using terms relating to COVID-19 and tuberculosis. We selected cohort and case–control studies for extraction and assessed quality with the Newcastle-Ottawa scale. Results and Conclusion: We identified 2108 unique abstracts published between December 2019 and January 2021. We extracted data from 18 studies from 8 countries. A total of 650,317 persons had a diagnosis of COVID-19, and 4179 had a diagnosis of current or prior tuberculosis. We explored links between tuberculosis and COVID-19 incidence, mortality, and other adverse outcomes. Nine studies reported on mortality and 13 on other adverse outcomes; results on the association between tuberculosis and COVID-19 mortality/adverse outcomes were heterogenous. Tuberculosis outcomes were not fully available in any studies, due to short follow-up (maximum of 3 months after COVID-19 diagnosis), so the effects of COVID-19 on tuberculosis outcomes could not be assessed. Much of the rapid influx of literature on tuberculosis and COVID-19 during this period was published on preprint servers, and therefore not peer-reviewed. It offered limited examination of the effect of tuberculosis on COVID-19 outcomes and even less on the effect of COVID-19 on tuberculosis treatment outcomes.

Disparities in SARS-CoV-2 Vaccination-to-Infection Risk During the COVID-19 Pandemic in Massachusetts

This cohort study examines the alignment of vaccination and SARS-CoV-2 risk in Massachusetts by creating and applying a vaccination-to-infection risk ratio.

The fourth national anti-tuberculosis drug resistance survey in Peru

BACKGROUND: Peru has one of the highest burdens of multidrug-resistant tuberculosis (MDR-TB), but universal drug susceptibility testing (DST) has not yet been achieved.OBJECTIVE: To estimate the proportion of drug resistance among smear-positive TB patients in Peru.DESIGN: From September 2014 to March 2015, we performed a national drug resistance survey of patients aged ≥15 years; TB was diagnosed based on sputum smear positivity. We performed DST at the National Reference Laboratory of the Peruvian National Institute of Health, Lima, Peru, using the proportion method in Middlebrook 7H10 agar for four first-line drugs and six second-line drugs, and the Wayne method for pyrazinamide.RESULTS: Of the 1908 new and 272 previously treated patients included in the analysis, 638 (29.3%) patients had resistance to at least one first-line drug. MDR-TB was diagnosed in 7.3% of new and 16.2% of previously treated patients (P < 0.001). There were five (0.2%) patients with extensively drug-resistant TB.CONCLUSION: MDR-TB has increased to 7.3% in new patients from 5.3% in the previous survey, indicating that resistance to anti-tuberculosis drugs is increasing in Peru. Ongoing community transmission of resistant strains highlights an urgent need for early diagnosis, optimised treatment and effective contact tracing of MDR-TB patients.

Prevalence of SARS-CoV-2 antibodies among market and city bus depot workers in Lima, Peru

We report severe acute respiratory syndrome coronavirus 2 antibody positivity among market and city bus depot workers in Lima, Peru. Among 1285 vendors from 8 markets, prevalence ranged from 27% to 73%. Among 488 workers from 3 city bus depots, prevalence ranged from 11% to 47%. Self-reported symptoms were infrequent.

Disparities in SARS-CoV-2 Testing in Massachusetts During the COVID-19 Pandemic

This cohort study examines disparities in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing during the coronavirus disease 2019 (COVID-19) pandemic in Massachusetts.

SARS-CoV-2 Testing Disparities in Massachusetts

OBJECTIVE

Early deficiencies in testing capacity contributed to poor control of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the context of marked improvement in SARS-CoV-2 testing infrastructure, we sought to examine the alignment of testing with epidemic intensity to mitigate subsequent waves of COVID-19 in Massachusetts.

METHODS

We compiled publicly available weekly SARS-CoV-2 molecular testing data for period (May 27 to October 14, 2020) following the initial COVID-19 wave. We defined testing intensity as weekly SARS-CoV-2 tests performed per 100,000 population and used weekly test positivity (percent of tests positive) as a measure of epidemic intensity. We considered optimal alignment of testing resources to be matching community ranks of testing and positivity. In communities with a lower rank of testing than positivity in a given week, the testing gap was calculated as the additional tests required to achieve matching ranks. Multivariable Poisson modeling was utilized to assess for trends and association with community characteristics.

RESULTS

During the observation period, 4,262,000 tests were reported in Massachusetts and the misalignment of testing with epidemic intensity increased. The weekly testing gap increased 9.0% per week (adjusted rate ratio [aRR]: 1.090, 95% confidence interval [CI]: 1.08-1.10). Increasing levels of community socioeconomic vulnerability (aRR: 1.35 per quartile increase, 95% CI: 1.23-1.50) and the highest quartile of minority and language vulnerability (aRR: 1.46, 95% CI 0.96-1.49) were associated with increased testing gaps, but the latter association was not statistically significant. Presence of large university student population (>10% of population) was associated with a marked decrease in testing gap (aRR 0.21, 95% CI: 0.12-0.38).

CONCLUSION

These analyses indicate that despite objectives to promote equity and enhance epidemic control in vulnerable communities, testing resources across Massachusetts have been disproportionally allocated to more affluent communities. Worsening structural inequities in access to SARS-CoV-2 testing increase the risk for another intense wave of COVID-19 in Massachusetts, particularly among vulnerable communities.

Omadacycline for the Treatment of Mycobacterium abscessus Disease: A Case Series

Background

Omadacycline is an aminomethylcycline antimicrobial approved by the US Food and Drug Administration in 2018 for community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections. It has in vitro activity against nontuberculous mycobacteria, including Mycobacterium abscessus complex, but clinical data for this indication are lacking.

Methods

Omadacycline use was reviewed at an 804-bed academic medical center. Patients were included if they received omadacycline for culture-proven M abscessus disease in 2019.

Results

Four patients received omadacycline for the treatment of culture-positive M abscessus disease in 2019. Two patients had cutaneous disease, 1 had pulmonary disease, and 1 had osteomyelitis and bacteremia. The patients received omadacycline for a median duration of 166 days (range, 104-227) along with a combination of other antimicrobial agents. Omadacycline-containing regimens were associated with a clinical cure in 3 of 4 patients, with 1 patient improving on ongoing treatment. Omadacycline's tolerability was acceptable for patients with M abscessus disease, with 1 patient discontinuing therapy in month 6 due to nausea.

Conclusions

Omadacycline is a novel oral option for the treatment of M abscessus disease, for which safe and effective options are needed. Although this case series is promising, further data are required to determine omadacycline's definitive role in the treatment of M abscessus disease.

Delayed Relapse of Paracoccidioidomycosis in the Central Nervous System: A Case Report

Paracoccidioidomycosis is a dimorphic fungal infection endemic in Latin America. We report a patient with a history of pulmonary paracoccidioidomycosis who presented with relapsed disease in the central nervous system 4 years after initial treatment. We review current treatment strategies for paracoccidioidomycosis and neuroparacoccidioidomycosis.

Efficacy and Safety of High-Dose Rifampin in Pulmonary Tuberculosis. A Randomized Controlled Trial

RATIONALE

We examined whether increased rifampin doses could shorten standard therapy for tuberculosis without increased toxicity.

OBJECTIVES

To assess the differences across three daily oral doses of rifampin in change in elimination rate of Mycobacterium tuberculosis in sputum and frequency of rifampin-related adverse events.

METHODS

We conducted a blinded, randomized, controlled phase 2 clinical trial of 180 adults with new smear-positive pulmonary tuberculosis, susceptible to isoniazid and rifampin. We randomized 1:1:1 to rifampin at 10, 15, and 20 mg/kg/d during the intensive phase. We report the primary efficacy and safety endpoints: change in elimination rate of M. tuberculosis log₁₀ colony-forming units and frequency of grade 2 or higher rifampin-related adverse events. We report efficacy by treatment arm and by primary (area under the plasma concentration-time curve [AUC]/minimum inhibitory concentration [MIC]) and secondary (AUC) pharmacokinetic exposure.

MEASUREMENTS AND MAIN RESULTS

Each 5-mg/kg/d increase in rifampin dose resulted in differences of -0.011 (95% confidence interval, -0.025 to +0.002; P = 0.230) and -0.022 (95% confidence interval, -0.046 to -0.002; P = 0.022) log₁₀ cfu/ml/d in the modified intention-to-treat and per-protocol analyses, respectively. The elimination rate in the per-protocol population increased significantly with rifampin AUC_0-6 (P = 0.011) but not with AUC_0-6/MIC_99.9 (P = 0.053). Grade 2 or higher rifampin-related adverse events occurred with similar frequency across the three treatment arms: 26, 31, and 23 participants (43.3%, 51.7%, and 38.3%, respectively) had at least one event (P = 0.7092) up to 4 weeks after the intensive phase. Treatment failed or disease recurred in 11 participants (6.1%).

CONCLUSIONS

Our findings of more rapid sputum sterilization and similar toxicity with higher rifampin doses support investigation of increased rifampin doses to shorten tuberculosis treatment. Clinical trial registered with www.clinicaltrials.gov (NCT 01408914) .

Quantitative assessment of the activity of antituberculosis drugs and regimens

Introduction: Identification of optimal drug doses and drug combinations is crucial for optimized treatment of tuberculosis. Areas covered: An unprecedented level of research activity involving multiple approaches is seeking to improve tuberculosis treatment. This report is a review of the quantitative methods currently used on clinical data sets to identify drug exposure targets and optimal drug combinations for tuberculosis treatment. A high-level summary of the methods, including the strengths and weaknesses of each method and potential methodological improvements is presented. Methods incorporating data generated from multiple sources such as in vitro and clinical studies, and their potential to provide better estimates of pharmacokinetic/pharmacodynamic (PK/PD) targets, are discussed. PK/PD relationships identified are compared between different studies and data analysis methods. Expert opinion: The relationships between drug exposures and tuberculosis treatment outcomes are complex and require analytical methods capable of handling the multidimensional nature of the relationships. The choice of a method is guided by its complexity, interpretability of results, and type of data available.

Outcomes of a Career Development Program for Underrepresented Minority Investigators in the AIDS Clinical Trials Group

We surveyed awardees of the Minority HIV Investigator Mentoring Program (MHIMP) of the AIDS Clinical Trials Group. Most reported clinical specialization in infectious diseases or HIV medicine (86%), and all but 1 (95%) are engaged in medical/health sciences research. The MHIMP helped retain early-career minority investigators in HIV/AIDS-related research.

A Case of Disseminated Histoplasmosis in a Patient with Rheumatoid Arthritis on Abatacept

Biologic agents are effective treatments for rheumatoid arthritis but are associated with important risks, including severe infections. Tumor Necrosis Factor (TNF) α inhibitors are known to increase the risk of systemic fungal infections such as disseminated histoplasmosis. Abatacept is a biologic agent with a mechanism different from that of TNFα inhibitors: It suppresses cellular immunity by competing for the costimulatory signal on antigen-presenting cells. The risk of disseminated histoplasmosis for patients on abatacept is not known. We report a case of abatacept-associated disseminated histoplasmosis and review the known infectious complications of abatacept. While the safety of resuming biologic agents following treatment for disseminated histoplasmosis is also not known, abatacept is recommended over TNFα inhibitors for rheumatoid arthritis patients with a prior serious infection. We discuss the evidence supporting this recommendation and discuss alternative treatments for rheumatoid arthritis patients with a history of a serious infection.

Prevalence of pyrazinamide resistance and Wayne assay performance analysis in a tuberculosis cohort in Lima, Peru

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) regimens often contain pyrazinamide (PZA) even if susceptibility to the drug has not been confirmed. This gap is due to the limited availability and reliability of PZA susceptibility testing.

OBJECTIVES

To estimate the prevalence of PZA resistance using the Wayne assay among TB patients in Lima, Peru, to describe characteristics associated with PZA resistance and to compare the performance of Wayne with that of BACTEC™ MGIT™ 960.

METHODS

PZA susceptibility using the Wayne assay was tested in patients diagnosed with culture-positive pulmonary TB from September 2009 to August 2012. Factors associated with PZA resistance were evaluated. We compared the performance of the Wayne assay to that of MGIT 960 in a convenience sample.

RESULTS

The prevalence of PZA resistance was 6.6% (95%CI 5.8-7.5) among 3277 patients, and 47.7% (95%CI 42.7-52.6) among a subset of 405 MDR-TB patients. In multivariable analysis, MDR-TB (OR 86.0, 95%CI 54.0-136.9) and Latin American-Mediterranean lineage (OR 3.40, 95%CI 2.33-4.96) were associated with PZA resistance. The Wayne assay was in agreement with MGIT 960 in 83.9% of samples (κ 0.66, 95%CI 0.56-0.76).

CONCLUSION

PZA resistance was detected using the Wayne assay in nearly half of MDR-TB patients in Lima. This test can inform the selection and composition of regimens, especially those dependent on additional resistance.

Nutritional Status and Tuberculosis Risk in Adult and Pediatric Household Contacts

BACKGROUND

Studies show obesity decreases risk of tuberculosis (TB) disease. There is limited evidence on whether high body mass index also protects against TB infection; how very high body mass indices influence TB risk; or whether nutritional status predicts this risk in children. We assessed the impact of body mass index on incident TB infection and disease among adults and children.

METHODS AND FINDINGS

We conducted a prospective cohort study among household contacts of pulmonary TB cases in Lima, Peru. We determined body mass index at baseline and followed participants for one year for TB infection and disease. We used Cox proportional regression analyses to estimate hazard ratios for incident TB infection and disease. We enrolled 14,044 household contacts, and among 6853 negative for TB infection and disease at baseline, 1787 (26.1%) became infected. A total of 406 contacts developed secondary TB disease during follow-up. Body mass index did not predict risk of TB infection but overweight household contacts had significantly decreased risk of TB disease (HR 0.48; 95% CI 0.37-0.64; p <0.001) compared to those with normal weight. Among adults, body mass index ≥ 35 kg/m2 continued to predict a lower risk of TB disease (HR 0.30; 95% CI 0.12-0.74; p 0.009). We found no association between high body mass index and TB infection or disease among children under 12 years of age.

CONCLUSIONS

High body mass index protects adults against TB disease even at levels ≥ 35 kg/m2. This protective effect does not extend to TB infection and is not seen in children.

Novel Ordered Stepped-Wedge Cluster Trial Designs for Detecting Ebola Vaccine Efficacy Using a Spatially Structured Mathematical Model

BACKGROUND

During the 2014 Ebola virus disease (EVD) outbreak, policy-makers were confronted with difficult decisions on how best to test the efficacy of EVD vaccines. On one hand, many were reluctant to withhold a vaccine that might prevent a fatal disease from study participants randomized to a control arm. On the other, regulatory bodies called for rigorous placebo-controlled trials to permit direct measurement of vaccine efficacy prior to approval of the products. A stepped-wedge cluster study (SWCT) was proposed as an alternative to a more traditional randomized controlled vaccine trial to address these concerns. Here, we propose novel "ordered stepped-wedge cluster trial" (OSWCT) designs to further mitigate tradeoffs between ethical concerns, logistics, and statistical rigor.

METHODOLOGY/PRINCIPAL FINDINGS

We constructed a spatially structured mathematical model of the EVD outbreak in Sierra Leone. We used the output of this model to simulate and compare a series of stepped-wedge cluster vaccine studies. Our model reproduced the observed order of first case occurrence within districts of Sierra Leone. Depending on the infection risk within the trial population and the trial start dates, the statistical power to detect a vaccine efficacy of 90% varied from 14% to 32% for standard SWCT, and from 67% to 91% for OSWCTs for an alpha error of 5%. The model's projection of first case occurrence was robust to changes in disease natural history parameters.

CONCLUSIONS/SIGNIFICANCE

Ordering clusters in a step-wedge trial based on the cluster's underlying risk of infection as predicted by a spatial model can increase the statistical power of a SWCT. In the event of another hemorrhagic fever outbreak, implementation of our proposed OSWCT designs could improve statistical power when a step-wedge study is desirable based on either ethical concerns or logistical constraints.

Impact of HIV on mortality among patients treated for tuberculosis in Lima, Peru: a prospective cohort study

Background

Human immunodeficiency virus (HIV)-associated tuberculosis deaths have decreased worldwide over the past decade. We sought to evaluate the effect of HIV status on tuberculosis mortality among patients undergoing treatment for tuberculosis in Lima, Peru, a low HIV prevalence setting.

Methods

We conducted a prospective cohort study of patients treated for tuberculosis between 2005 and 2008 in two adjacent health regions in Lima, Peru (Lima Ciudad and Lima Este). We constructed a multivariate Cox proportional hazards model to evaluate the effect of HIV status on mortality during tuberculosis treatment.

Results

Of 1701 participants treated for tuberculosis, 136 (8.0 %) died during tuberculosis treatment. HIV-positive patients constituted 11.0 % of the cohort and contributed to 34.6 % of all deaths. HIV-positive patients were significantly more likely to die (25.1 vs. 5.9 %, P < 0.001) and less likely to be cured (28.3 vs. 39.4 %, P = 0.003). On multivariate analysis, positive HIV status (hazard ratio [HR] = 6.06; 95 % confidence interval [CI], 3.96–9.27), unemployment (HR = 2.24; 95 % CI, 1.55–3.25), and sputum acid-fast bacilli smear positivity (HR = 1.91; 95 % CI, 1.10–3.31) were significantly associated with a higher hazard of death.

Conclusions

We demonstrate that positive HIV status was a strong predictor of mortality among patients treated for tuberculosis in the early years after Peru started providing free antiretroviral therapy. As HIV diagnosis and antiretroviral therapy provision are more widely implemented for tuberculosis patients in Peru, future operational research should document the changing profile of HIV-associated tuberculosis mortality.

Time From Infection to Disease and Infectiousness for Ebola Virus Disease, a Systematic Review

We systematically reviewed the literature to estimate the incubation and latent periods of Ebola virus disease. We found limited epidemiological data from individuals with discrete 1-day exposures. Available data suggest that the incubation and latent periods may differ, and mathematical models may be improved by distinguishing between the two periods.

Improving outcomes for multidrug-resistant tuberculosis: aggressive regimens prevent treatment failure and death

BACKGROUND

Evidence is sparse regarding the optimal construction of regimens to treat multidrug-resistant (MDR) tuberculosis disease due to strains of Mycobacterium tuberculosis resistant to at least both isoniazid and rifampin. Given the low potency of many second-line antituberculous drugs, we hypothesized that an aggressive regimen of at least 5 likely effective drugs during the intensive phase, including a fluoroquinolone and a parenteral agent, would be associated with a reduced risk of death or treatment failure.

METHODS

We conducted a retrospective cohort study of patients initiating MDR tuberculosis treatment between 2000 and 2004 in Tomsk, Russian Federation. We used a multivariate Cox proportional hazards model to assess whether monthly exposure to an aggressive regimen was associated with the risk of death or treatment failure.

RESULTS

Six hundred fourteen individuals with confirmed MDR tuberculosis were eligible for analysis. On multivariable analysis that adjusted for extensively drug-resistant (XDR) tuberculosis-MDR tuberculosis isolates resistant to fluoroquinolones and parenteral agents-we found that monthly exposure to an aggressive regimen was significantly associated with a lower risk of death or treatment failure (hazard ratio, 0.52 [95% confidence interval, .29-.94]; P = .030).

CONCLUSIONS

Receipt of an aggressive treatment regimen was a robust predictor of decreased risk of death or failure during MDR tuberculosis treatment. These findings further support the use of this regimen definition as the benchmark for the standard of care of MDR tuberculosis patients and should be used as the basis for evaluating novel therapies.

Targeted drug-resistance testing strategy for multidrug-resistant tuberculosis detection, Lima, Peru, 2005-2008

Running head: Targeted Drug-Resistance Testing Strategy for MDR TB

The Peruvian National Tuberculosis Control Program issued guidelines in 2006 specifying criteria for culture and drug-susceptibility testing (DST), including district-level rapid DST. All patients referred for culture and DST in 2 districts of Lima, Peru, during January 2005–November 2008 were monitored prospectively. Of 1,846 patients, 1,241 (67.2%) had complete DST results for isoniazid and rifampin; 419 (33.8%) patients had multidrug-resistant (MDR) TB at the time of referral. Among patients with new smear-positive TB, household contact and suspected category I failure were associated with MDR TB, compared with concurrent regional surveillance data. Among previously treated patients with smear-positive TB, adult household contact, suspected category II failure, early relapse after category I, and multiple previous TB treatments were associated with MDR TB, compared with concurrent regional surveillance data. The proportion of MDR TB detected by using guidelines was higher than that detected by a concurrent national drug-resistance survey, indicating that the strategy effectively identified patients for DST.