Nebulised interferon-ß1a (SNG001) in hospitalised COVID-19: SPRINTER phase III study.

Background: Despite the availability of vaccines and therapies, patients are being hospitalised with coronavirus disease 2019 (COVID-19). Interferon (IFN)-ß is a naturally occurring protein that stimulates host immune responses against most viruses, including severe acute respiratory syndrome coronavirus 2. SNG001 is a recombinant IFN-ß1a formulation delivered to the lungs via nebuliser. SPRINTER assessed the efficacy and safety of SNG001 in adults hospitalised due to COVID-19 who required oxygen via nasal prongs or mask. Methods: Patients were randomised double-blind to SNG001 (n=309) or placebo (n=314) once daily for 14 days plus standard of care (SoC). The primary objective was to evaluate recovery after administration of SNG001 versus placebo, in terms of times to hospital discharge and recovery to no limitation of activity. Key secondary end-points were progression to severe disease or death, progression to intubation or death and death. Results: Median time to hospital discharge was 7.0 and 8.0 days with SNG001 and placebo, respectively (hazard ratio (HR) 1.06 (95% CI 0.89-1.27); p=0.51); time to recovery was 25.0 days in both groups (HR 1.02 (95% CI 0.81-1.28); p=0.89). There were no significant SNG001-placebo differences for the key secondary end-points, with a 25.7% relative risk reduction in progression to severe disease or death (10.7% and 14.4%, respectively; OR 0.71 (95% CI 0.44-1.15); p=0.161). Serious adverse events were reported by 12.6% and 18.2% patients with SNG001 and placebo, respectively. Conclusions: Although the primary objective of the study was not met, SNG001 had a favourable safety profile, and the key secondary end-points analysis suggested that SNG001 may have prevented progression to severe disease.

PROphylaxis for paTiEnts at risk of COVID-19 infecTion (PROTECT-V).

BACKGROUND: Despite the introduction of vaccination, there remains a need for pre-exposure prophylactic agents against SARS-CoV-2. Several patient groups are more vulnerable to SARS-CoV-2 infection by virtue of underlying health conditions, treatments received or suboptimal responses to vaccination. METHODS: PROTECT-V is a platform trial testing pre-exposure prophylactic interventions against SARS-CoV-2 infection in vulnerable patient populations (organ transplant recipients; individuals with oncological/haematological diagnoses, immune deficiency or autoimmune diseases requiring immunosuppression or on dialysis). Multiple agents can be evaluated across multiple vulnerable populations sharing placebo groups, with the option of adding additional treatments at later time points as these become available. The primary endpoint is symptomatic SARS-CoV-2 infection, and each agent will be independently evaluated in real time when the required number of events occurs. Presently, three agents are approved in the platform: intranasal niclosamide, nasal and inhaled ciclesonide and intravenous sotrovimab. DISCUSSION: Despite the introduction of vaccination, there remains a need for pre-exposure prophylactic agents against SARS-CoV-2. Several patient groups are more vulnerable to COVID-19 disease by virtue of underlying health conditions, treatments received or suboptimal responses to vaccination. TRIAL REGISTRATION: ClinicalTrials.gov NCT04870333. EudraCT 2020-004144-28.

Dipeptidyl peptidase-1 inhibition in patients hospitalised with COVID-19: a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial.

BACKGROUND: Neutrophil serine proteases are involved in the pathogenesis of COVID-19 and increased serine protease activity has been reported in severe and fatal infection. We investigated whether brensocatib, an inhibitor of dipeptidyl peptidase-1 (DPP-1; an enzyme responsible for the activation of neutrophil serine proteases), would improve outcomes in patients hospitalised with COVID-19. METHODS: In a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial, across 14 hospitals in the UK, patients aged 16 years and older who were hospitalised with COVID-19 and had at least one risk factor for severe disease were randomly assigned 1:1, within 96 h of hospital admission, to once-daily brensocatib 25 mg or placebo orally for 28 days. Patients were randomly assigned via a central web-based randomisation system (TruST). Randomisation was stratified by site and age (65 years or ≥65 years), and within each stratum, blocks were of random sizes of two, four, or six patients. Participants in both groups continued to receive other therapies required to manage their condition. Participants, study staff, and investigators were masked to the study assignment. The primary outcome was the 7-point WHO ordinal scale for clinical status at day 29 after random assignment. The intention-to-treat population included all patients who were randomly assigned and met the enrolment criteria. The safety population included all participants who received at least one dose of study medication. This study was registered with the ISRCTN registry, ISRCTN30564012. FINDINGS: Between June 5, 2020, and Jan 25, 2021, 406 patients were randomly assigned to brensocatib or placebo; 192 (47·3%) to the brensocatib group and 214 (52·7%) to the placebo group. Two participants were excluded after being randomly assigned in the brensocatib group (214 patients included in the placebo group and 190 included in the brensocatib group in the intention-to-treat population). Primary outcome data was unavailable for six patients (three in the brensocatib group and three in the placebo group). Patients in the brensocatib group had worse clinical status at day 29 after being randomly assigned than those in the placebo group (adjusted odds ratio 0·72 [95% CI 0·57-0·92]). Prespecified subgroup analyses of the primary outcome supported the primary results. 185 participants reported at least one adverse event; 99 (46%) in the placebo group and 86 (45%) in the brensocatib group. The most common adverse events were gastrointestinal disorders and infections. One death in the placebo group was judged as possibly related to study drug. INTERPRETATION: Brensocatib treatment did not improve clinical status at day 29 in patients hospitalised with COVID-19. FUNDING: Sponsored by the University of Dundee and supported through an Investigator Initiated Research award from Insmed, Bridgewater, NJ; STOP-COVID19 trial.

Utility of severity assessment tools in COVID-19 pneumonia: a multicentre observational study.

BACKGROUND: Severity scores in pneumonia and sepsis are being applied to SARS-CoV-2 infection. We aimed to assess whether these severity scores are accurate predictors of early adverse outcomes in COVID-19. METHODS: We conducted a multicentre observational study of hospitalised SARS-CoV-2 infection. We assessed risk scores (CURB65, qSOFA, Lac-CURB65, MuLBSTA and NEWS2) in relation to admission to intensive care or death within 7 days of admission, defined as early severe adverse events (ESAE). The 4C Mortality Score was also assessed in a sub-cohort of patients. FINDINGS: In 2,387 participants, the overall mortality was 18%. In all scores examined, increasing score was associated with increased risk of ESAE. Area under the curve (AUC) to predict ESAE for CURB65, qSOFA, Lac-CURB65, MuLBSTA and NEWS2 were 0.61, 0.62, 0.59, 0.59 and 0.68, respectively. AUC to predict ESAE was 0.60 with ISARIC 4C Mortality Score. CONCLUSION: None of the scores examined accurately predicted ESAE in SARS-CoV-2 infection. Non-validated scores should not be used to inform clinical decision making in COVID-19.

COVID-19 admission risk tools should include multiethnic age structures, multimorbidity and deprivation metrics for air pollution, household overcrowding, housing quality and adult skills.

BACKGROUND: Ethnic minorities account for 34% of critically ill patients with COVID-19 despite constituting 14% of the UK population. Internationally, researchers have called for studies to understand deterioration risk factors to inform clinical risk tool development. METHODS: Multicentre cohort study of hospitalised patients with COVID-19 (n=3671) exploring determinants of health, including Index of Multiple Deprivation (IMD) subdomains, as risk factors for presentation, deterioration and mortality by ethnicity. Receiver operator characteristics were plotted for CURB65 and ISARIC4C by ethnicity and area under the curve (AUC) calculated. RESULTS: Ethnic minorities were hospitalised with higher Charlson Comorbidity Scores than age, sex and deprivation matched controls and from the most deprived quintile of at least one IMD subdomain: indoor living environment (LE), outdoor LE, adult skills, wider barriers to housing and services. Admission from the most deprived quintile of these deprivation forms was associated with multilobar pneumonia on presentation and ICU admission. AUC did not exceed 0.7 for CURB65 or ISARIC4C among any ethnicity except ISARIC4C among Indian patients (0.83, 95% CI 0.73 to 0.93). Ethnic minorities presenting with pneumonia and low CURB65 (0-1) had higher mortality than White patients (22.6% vs 9.4%; p<0.001); Africans were at highest risk (38.5%; p=0.006), followed by Caribbean (26.7%; p=0.008), Indian (23.1%; p=0.007) and Pakistani (21.2%; p=0.004). CONCLUSIONS: Ethnic minorities exhibit higher multimorbidity despite younger age structures and disproportionate exposure to unscored risk factors including obesity and deprivation. Household overcrowding, air pollution, housing quality and adult skills deprivation are associated with multilobar pneumonia on presentation and ICU admission which are mortality risk factors. Risk tools need to reflect risks predominantly affecting ethnic minorities.

Coronary artery thrombus resulting in ST-elevation myocardial infarction in a patient with COVID-19.

COVID-19 is a prothrombotic condition that is also associated with raised troponin levels and myocardial damage. We present a case of a 54-year-old man who was admitted with respiratory failure due to COVID-19 and developed a ST-elevation myocardial infarction (STEMI) during his admission. His coronary angiogram did not show any significant coronary artery disease other than a heavily thrombosed right coronary artery. In view of heavy thrombus burden, the right coronary artery was treated with thrombus retrieval using a distal embolic protection device in addition to manual thrombectomy and direct (intracoronary) thrombolysis without the need for implantation of a coronary stent. After successful revascularisation, triple antithrombotic therapy was instituted with an oral anticoagulant in addition to dual antiplatelets. This case illustrates the association of COVID-19 with coronary artery thrombosis, which may require disparate management of a STEMI than that resulting from atherosclerotic coronary artery disease.

Increase in recruitment upon integration of trial into a clinical care pathway: an observational study.

INTRODUCTION: Many respiratory clinical trials fail to reach their recruitment target and this problem exacerbates existing funding issues. Integration of the clinical trial recruitment process into a clinical care pathway (CCP) may represent an effective way to significantly increase recruitment numbers. METHODS: A respiratory support unit and a CCP for escalation of patients with severe COVID-19 were established on 11 January 2021. The recruitment process for the Randomised Evaluation of COVID-19 Therapy-Respiratory Support trial was integrated into the CCP on the same date. Recruitment data for the trial were collected before and after integration into the CCP. RESULTS: On integration of the recruitment process into a CCP, there was a significant increase in recruitment numbers. Fifty patients were recruited over 266 days before this process occurred whereas 108 patients were recruited over 49 days after this process. There was a statistically significant increase in both the proportion of recruited patients relative to the number of COVID-19 hospital admissions (change from 2.8% to 9.1%, p<0.0001) and intensive therapy unit admissions (change from 17.8% to 50.2%, p<0.001) over the same period, showing that this increase in recruitment was independent of COVID-19 prevalence. DISCUSSION: Integrating the trial recruitment process into a CCP can significantly boost recruitment numbers. This represents an innovative model that can be used to maximise recruitment without impacting on the financial and labour costs associated with the running of a respiratory clinical trial.

Real-world retrospective observational study exploring the effectiveness and safety of antifibrotics in idiopathic pulmonary fibrosis.

BACKGROUND: Pirfenidone and nintedanib are the only disease-modifying treatments available for idiopathic pulmonary fibrosis (IPF). Our aim was to test their effectiveness and safety in clinical practice. METHODS: This is a single-centre retrospective observational study undertaken at a specialised interstitial lung disease centre in England. Data including progression-free survival (PFS), mortality and drug tolerability were compared between patients with IPF on antifibrotic therapies and an untreated control group who had a forced vital capacity percentage (FVC %) predicted within the licensed antifibrotic treatment range. RESULTS: 104 patients received antifibrotic therapies and 64 control patients were identified. PFS at 6 months was significantly greater in the antifibrotic group (75.0%) compared with the control group (56.3%) (p=0.012). PFS was not significant at 12 or 18 months when comparing the antifibrotic group with the control group. The 12-month post-treatment mean decline in FVC % predicted (-4.6±6.2%) was significantly less than the 12-month pretreatment decline (-10.4±11.8%) (p=0.039). The 12-month mortality rate was not significantly different between the antifibrotic group (25.3%) and the control group (35.5%) (p=0.132). Baseline Body Mass Index of≤25, baseline diffusion capacity for carbon monoxide percentage predicted of ≤35 and antifibrotic discontinuation within 3 months were independent predictors of 12-month mortality. Antifibrotic discontinuation was significantly higher by 3 and 6 months for patients on pirfenidone than those on nintedanib (p=0.006 and p=0.044, respectively). Discontinuation at 12 months was not significantly different (p=0.381). CONCLUSIONS: This real-world study revealed that antifibrotics are having promising effects on PFS, lung function and mortality. These findings may favour commencement of nintedanib as first-line antifibrotic therapy, given the lower rates of early treatment discontinuation, although further studies are required to investigate this.

Outcome of Hospitalization for COVID-19 in Patients with Interstitial Lung Disease. An International Multicenter Study.

Rationale: The impact of coronavirus disease (COVID-19) on patients with interstitial lung disease (ILD) has not been established.Objectives: To assess outcomes in patients with ILD hospitalized for COVID-19 versus those without ILD in a contemporaneous age-, sex-, and comorbidity-matched population.Methods: An international multicenter audit of patients with a prior diagnosis of ILD admitted to the hospital with COVID-19 between March 1 and May 1, 2020, was undertaken and compared with patients without ILD, obtained from the ISARIC4C (International Severe Acute Respiratory and Emerging Infection Consortium Coronavirus Clinical Characterisation Consortium) cohort, admitted with COVID-19 over the same period. The primary outcome was survival. Secondary analysis distinguished idiopathic pulmonary fibrosis from non-idiopathic pulmonary fibrosis ILD and used lung function to determine the greatest risks of death.Measurements and Main Results: Data from 349 patients with ILD across Europe were included, of whom 161 were admitted to the hospital with laboratory or clinical evidence of COVID-19 and eligible for propensity score matching. Overall mortality was 49% (79/161) in patients with ILD with COVID-19. After matching, patients with ILD with COVID-19 had significantly poorer survival (hazard ratio [HR], 1.60; confidence interval, 1.17-2.18; P = 0.003) than age-, sex-, and comorbidity-matched controls without ILD. Patients with an FVC of <80% had an increased risk of death versus patients with FVC ≥80% (HR, 1.72; 1.05-2.83). Furthermore, obese patients with ILD had an elevated risk of death (HR, 2.27; 1.39-3.71).Conclusions: Patients with ILD are at increased risk of death from COVID-19, particularly those with poor lung function and obesity. Stringent precautions should be taken to avoid COVID-19 in patients with ILD.

Early identification of severe community-acquired pneumonia: a retrospective observational study.

Background: Community-acquired pneumonia (CAP) is a leading cause of sepsis worldwide. Prompt identification of those at high risk of adverse outcomes improves survival by enabling early escalation of care. There are multiple severity assessment tools recommended for risk stratification; however, there is no consensus as to which tool should be used for those with CAP. We sought to assess whether pneumonia-specific, generic sepsis or early warning scores were most accurate at predicting adverse outcomes. Methods: We performed a retrospective analysis of all cases of CAP admitted to a large, adult tertiary hospital in the UK between October 2014 and January 2016. All cases of CAP were eligible for inclusion and were reviewed by a senior respiratory physician to confirm the diagnosis. The association between the CURB65, Lac-CURB-65, quick Sequential (Sepsis-related) Organ Failure Assessment tool (qSOFA) score and National Early Warning Score (NEWS) at the time of admission and outcome measures including intensive care admission, length of hospital stay, in-hospital, 30-day, 90-day and 365-day all-cause mortality was assessed. Results: 1545 cases were included with 30-day mortality of 19%. Increasing score was significantly associated with increased risk of poor outcomes for all four tools. Overall accuracy assessed by receiver operating characteristic curve analysis was significantly greater for the CURB65 and Lac-CURB-65 scores than qSOFA. At admission, a CURB65 ≥2, Lac-CURB-65 ≥moderate, qSOFA ≥2 and NEWS ≥medium identified 85.0%, 96.4%, 40.3% and 79.0% of those who died within 30 days, respectively. A Lac-CURB-65 ≥moderate had the highest negative predictive value: 95.6%. Conclusion: All four scoring systems can stratify according to increasing risk in CAP; however, when a confident diagnosis of pneumonia can be made, these data support the use of pneumonia-specific tools rather than generic sepsis or early warning scores.

Pro-inflammatory effects of e-cigarette vapour condensate on human alveolar macrophages.

OBJECTIVE: Vaping may increase the cytotoxic effects of e-cigarette liquid (ECL). We compared the effect of unvaped ECL to e-cigarette vapour condensate (ECVC) on alveolar macrophage (AM) function. METHODS: AMs were treated with ECVC and nicotine-free ECVC (nfECVC). AM viability, apoptosis, necrosis, cytokine, chemokine and protease release, reactive oxygen species (ROS) release and bacterial phagocytosis were assessed. RESULTS: Macrophage culture with ECL or ECVC resulted in a dose-dependent reduction in cell viability. ECVC was cytotoxic at lower concentrations than ECL and resulted in increased apoptosis and necrosis. nfECVC resulted in less cytotoxicity and apoptosis. Exposure of AMs to a sub-lethal 0.5% ECVC/nfECVC increased ROS production approximately 50-fold and significantly inhibited phagocytosis. Pan and class one isoform phosphoinositide 3 kinase inhibitors partially inhibited the effects of ECVC/nfECVC on macrophage viability and apoptosis. Secretion of interleukin 6, tumour necrosis factor α, CXCL-8, monocyte chemoattractant protein 1 and matrix metalloproteinase 9 was significantly increased following ECVC challenge. Treatment with the anti-oxidant N-acetyl-cysteine (NAC) ameliorated the cytotoxic effects of ECVC/nfECVC to levels not significantly different from baseline and restored phagocytic function. CONCLUSIONS: ECVC is significantly more toxic to AMs than non-vaped ECL. Excessive production of ROS, inflammatory cytokines and chemokines induced by e-cigarette vapour may induce an inflammatory state in AMs within the lung that is partly dependent on nicotine. Inhibition of phagocytosis also suggests users may suffer from impaired bacterial clearance. While further research is needed to fully understand the effects of e-cigarette exposure in humans in vivo, we caution against the widely held opinion that e-cigarettes are safe.

Oxygen prescription: improving compliance using methods from BMJ Open Quality journal.

Oxygen is an important drug frequently used in the management of acutely unwell hospital patients. However, oxygen overuse can have fatal side effects particularly for those patients at risk of iatrogenic hypercapnia. British Thoracic Society Guidelines state that oxygen must be prescribed for all patients, with target saturations stipulated on the prescription for patient safety. A quality improvement project was undertaken with the aim to improve the oxygen prescription rate across the respiratory ward at a district general hospital, over a period of 3 months. Quality improvement methods were implemented based on data analysis at each stage, following discussion with senior doctors and specialist nurses, and after reviewing previous quality improvement projects published on BMJ Open Quality. The initial interventions of poster reminders and multidisciplinary team education failed to significantly improve the rates of oxygen prescription. Use of a targeted intervention where stickers were placed above oxygen taps significantly improved prescription rate from 20% in the non-targeted group to 60% in the targeted group. This was based on a BMJ Open Quality published improvement method. The current guidelines from the British Thoracic Society, and hospital's own guidelines, advise good oxygen prescribing. However, these recommendations alone are ineffective at achieving compliance among prescribers. Further targeted interventions have shown improvements in oxygen prescriptions and could lead to better clinical practice, patient care and safety.

Sepsis Induces a Dysregulated Neutrophil Phenotype That Is Associated with Increased Mortality.

BACKGROUND: Neutrophil dysfunction in sepsis has been implicated in the pathogenesis of multiorgan failure; however, the role of neutrophil extracellular traps (NETs) remains uncertain. We aimed to determine the sequential changes in ex vivo NETosis and its relationship with mortality in patients with sepsis and severe sepsis. METHODS: This was a prospective observational cohort study enrolling 21 healthy age-matched controls and 39 sepsis and 60 severe sepsis patients from acute admissions to two UK hospitals. Patients had sequential bloods for the ex vivo assessment of NETosis in response to phorbol-myristate acetate (PMA) using a fluorometric technique and chemotaxis using time-lapse video microscopy. Continuous data was tested for normality, with appropriate parametric and nonparametric tests, whilst categorical data was analysed using a chi-squared test. Correlations were performed using Spearman's rho. RESULTS: Ex vivo NETosis was reduced in patients with severe sepsis, compared to patients with sepsis and controls (p = 0.002). PMA NETosis from patients with septic shock was reduced further (p < 0.001) compared to controls. The degree of metabolic acidosis correlated with reduced NETosis (p < 0.001), and this was replicated when neutrophils from healthy donors were incubated in acidotic media. Reduced NETosis at baseline was associated with an increased 30-day (p = 0.002) and 90-day mortality (p = 0.014) in sepsis patients. These findings were accompanied by defects in neutrophil migration and delayed apoptosis. Resolution of sepsis was not associated with the return to baseline levels of NETosis or migration. CONCLUSIONS: Sepsis induces significant changes in neutrophil function with the degree of dysfunction corresponding to the severity of the septic insult which persists beyond physiological recovery from sepsis. The changes induced lead to the failure to effectively contain and eliminate the invading pathogens and contribute to sepsis-induced immunosuppression. For the first time, we demonstrate that reduced ex vivo NETosis is associated with poorer outcomes from sepsis.

Statin therapy in patients with community-acquired pneumonia.

Community-acquired pneumonia (CAP) is the leading cause of death from infection in developed countries. There is evidence of an association between improved survival from infection and statin use. The possible beneficial effects of statins are complicated by the common use of macrolide antibiotics for pneumonia, with current guidance suggesting that concurrent macrolide and statin use is contraindicated.We conducted an observational study of statin use in patients with CAP. Of 2,067 patients with CAP, 30.4% were on statin therapy at admission. Statin users were more likely to survive the admission (p<0.001). In addition, we conducted a survey of doctors and found that knowledge regarding concurrent macrolide and statin use was lacking.These data suggest a potential role of statins in the management of CAP. Further research using high-dose statins is required to assess their safe use in subjects with mild to moderate infections.

Increased risk of Mycobacterium tuberculosis infection in household child contacts exposed to passive tobacco smoke.

Risk factors associated with Mycobacterium tuberculosis infection were investigated in a prospective cohort of household child tuberculosis contacts. A significantly increased risk of acquiring infection was associated with exposure to passive cigarette smoke, higher number of index cases, younger age and reduced household monthly income.

Patient reported outcomes and their importance in the development of novel surgical techniques.

INTRODUCTION: Although traditional quality measures such as morbidity and mortality outcomes still pay an important role in the assessment of health care quality, greater emphasis is now being placed on patient-reported outcome measures such as patient satisfaction. This area is especially important for novel surgical technologies such as single-incision laparoscopic surgery (SILS) and natural orifice translumenal endoscopic surgery (NOTES). These new innovations are able to minimize or abolish surgical scarring and are likely to have most benefit in the area of patient satisfaction as opposed to traditional outcome measures. Therefore, it is important to gauge the public opinion regarding these new techniques, as continued public interest can help support further research in this up-and-coming field. METHODS: A questionnaire study was carried out with members of the general public. Questions were asked regarding preference for surgical techniques, including open surgery, laparoscopic surgery, NOTES, and SILS, in the situation of acute appendicitis. RESULTS: The questionnaire was completed by 1006 individuals. Results indicated that an established safety profile was necessary before the introduction of these new techniques into general practice. The concept of scarless surgery did appeal to the public, with SILS being the treatment of choice in the scenario of acute appendicitis. DISCUSSION: The patient perspective on health care is an important aspect of health care quality assessment. This is especially important with regard to the development of novel surgical techniques such as SILS and NOTES. With these techniques, the potential benefits are most likely to be found in the realms of reduced scarring and improved patient satisfaction. The findings from this study demonstrate the public's interest in these new techniques and thus give further support to continued research and development in this area.

Novel M tuberculosis antigen-specific T-cells are early markers of infection and disease progression.

BACKGROUND: Mycobacterium tuberculosis Region-of-Difference-1 gene products present opportunities for specific diagnosis of M. tuberculosis infection, yet immune responses to only two gene-products, Early Secretory Antigenic Target-6 (ESAT-6) and Culture Filtrate Protein-10 (CFP-10), have been comprehensively investigated. METHODS: T-cell responses to Rv3873, Rv3878 and Rv3879c were quantified by IFN-γ-enzyme-linked-immunospot (ELISpot) in 846 children with recent household tuberculosis exposure and correlated with kinetics of tuberculin skin test (TST) and ESAT-6/CFP-10-ELISpot conversion over six months and clinical outcome over two years. RESULTS: Responses to Rv3873, Rv3878, and Rv3879c were present in 20-25% of contacts at enrolment. Rv3873 and Rv3879c responses were associated with and preceded TST conversion (P=0.02 and P=0.04 respectively), identifying these antigens as early targets of cell-mediated immunity following M. tuberculosis exposure. Responses to Rv3873 were additionally associated with subsequent ESAT-6/CFP-10-ELISpot conversion (P=0.04). Responses to Rv3873 and Rv3878 predicted progression to active disease (adjusted incidence rate ratio [95% CI] 3.06 [1.05,8.95; P=0.04], and 3.32 [1.14,9.71; P=0.03], respectively). Presence of a BCG-vaccination scar was associated with a 67% (P=0.03) relative risk reduction for progression to active tuberculosis. CONCLUSIONS: These RD1-derived antigens are early targets of cellular immunity following tuberculosis exposure and T-cells specific for these antigens predict progression to active tuberculosis suggesting diagnostic and prognostic utility.