Low- and high-volume blood-flow restriction treadmill walking both improve maximal aerobic capacity independently of blood volume.

AIM: Assess the effect of low- and high-volume blood flow restriction training (BFR) on maximal aerobic capacity (VO2 max) and determine if alteration in VO2 max is mediated through changes in hemoglobin mass (Hbmass) and blood volume. METHODS: Participants' Hbmass (CO-rebreathe), single, and double-leg VO2 max and blood volume regulating hormonal responses (renin and copeptin) were measured before and after BFR training. Training consisted of treadmill walking either (1) twice-daily for 4week (CON and BFRHV ) or (2) twice-weekly for 6week (BFRLV ). Each session consisted of five intervals (3 min, 5% incline, 5 km/h, 100% of lowest occlusion pressure), with 1 min of standing rest between sets. RESULTS: VO2 max increased using both training exposures, in as quickly as 2-weeks (BFRLV baseline to 4week: +315 ± 241 mL (8.7%), p = 0.02; BFRHV baseline to 2week: +360 ± 261 mL (7.9%), p < 0.01), for the BFRLV and BFRHV groups, with no change in CON. Single- and double-leg VO2 max improved proportionately (single/double-leg VO2 max ratio: BFRLV 78 ± 4.9-78 ± 5.8%, BFRHV 79 ± 6.5-77 ± 6.5%), suggesting that the mechanism for increased VO2 max is not solely limited to central or peripheral adaptations. Hbmass remained unchanged across groups (CON: +10.2 ± 34 g, BFRLV : +6.6 ± 42 g, BFRHV : +3.2 ± 44 g; p = 0.9), despite a significant release of blood volume regulating hormones after initial BFR exposure (renin +20.8 ± 21.9 ng/L, p < 0.01; copeptin +22.0 ± 23.8 pmol/L, p < 0.01), which was blunted following BFRHV training (renin: +13.4 ± 12.4 ng/L, p = 0.09; copeptin: +1.9 ± 1.7 pmol/L, p = 0.98). CONCLUSION: BFR treadmill walking increases VO2 max irrespective of changes in Hbmass or blood volume despite a large release of blood volume regulating hormones in response to BFR treadmill walking.

Epidemiology of occupational exposure to blood-borne viruses, postexposure prophylaxis and seroconversion over 10 years among healthcare workers.

BACKGROUND: Healthcare workers (HCWs) are at increased risk of infection with blood-borne pathogens due to occupational blood exposures (OBEs). Early reporting, detection and postexposure prophylaxis (PEP) help to prevent infections. AIM: To investigate the incidence of OBEs, related epidemiological characteristics, PEP completion rate, time and reason for PEP discontinuation, and seroconversion rate reported over 10 years. METHODS: This retrospective study analysed 1086 cases of OBE and PEP management from January 2012 to December 2021 among staff in a South Korean tertiary hospital. FINDINGS: The mean incidence of OBE was 7.82 per 100 beds and 3.0 per 100 HCWs. Of 1086 cases of OBE, 633 (58.3%) HCWs required PEP and 453 (41.7%) did not. After OBE, 70.1% (444/633) of HCWs subject to PEP completed tracking, and 29.9% (189/633) stopped PEP tracking (P<0.001). The PEP completion rate showed a significant difference by gender (P=0.024), occupation (P<0.001) and exposure frequency (P<0.001). None of the 444 HCWs who completed PEP seroconverted to hepatitis B virus, hepatitis C virus, human immunodeficiency virus or Treponema pallidum (syphilis). CONCLUSION: The study findings demonstrate the need to improve follow-up care among HCWs following OBE. There is a need for education in healthcare facilities; moreover, establishing a national surveillance system is necessary to ensure that HCWs undergo PEP proactively and complete their follow-up visits.

RADIOLOGICAL IMPACT OF USING DECORATIVE GRANITE AS AN ATTENUATOR OF IONIZING RADIATION.

Granite is a widely available rock, which can be used as a shielding material, for bulk in the form of the aggregate in concrete. It has the weakness that it is more radioactive than many other rocks, which can be used in concrete. This paper looks at its properties as a shielding material and the activity level. Thus, the concentrations of 226Ra, 232Th and 40K, in granite were measured using a high pure germanium detector (HPGe). They were ranged from (15 ± 4 to 49 ± 5) Bq kg-1 for 226Ra, (22 ± 4 to 78 ± 4 Bq kg-1) for 232Th and (791 ± 13 to 1231 ± 15 Bq kg-1) for 40K. Radiological indices of radium equivalent concentration (Raeq), external (Hex), internal (Hin) and annual effective dose were less than worldwide recommended limits. The results emphasized, the granite samples had no radiation hazard. Nevertheless, the mass attenuation coefficients of granite samples were measured for the gamma rays of energy range 122-1408 keV. The mass attenuation coefficients of the studied granite samples were ranged from 0.05 to 0.15 cm2 g-1. In addition, the average the half-value layer of granite was varied from 1.8 cm for 122 keV to 5.2 cm for 1408 keV. The results are that the attenuation characteristics are typical and match the values given by NIST for 'concrete' and that the activity levels of the samples examined are acceptable. Thus the granite may be used as an attenuator for ionizing radiation.

The efficacy of immune checkpoint inhibitors in elderly patients: a meta-analysis and meta-regression.

BACKGROUND: Immune checkpoint inhibitor (ICI) therapy has improved patient survival in advanced cancers; however, the efficacy of ICIs in elderly patients is still elusive. This study assessed the efficacy of ICIs in elderly patients with advanced cancer in terms of overall survival (OS) and progression-free survival (PFS). MATERIALS AND METHODS: We carried out a systematic review and identified 30 head-to-head phase II/III randomized controlled trials that compared immunotherapy with the standard of care in advanced solid tumor patients. The data on patients younger or over 65 years of age were indexed from PubMed-Medline, Embase, and Scopus and obtained for meta-analysis. The subgroup analyses were stratified by primary tumor type, line of treatment, or type of immunotherapy, and a meta-regression analysis was carried out after adjusting for all other variables. RESULTS: The study included 17 476 patients, comprising 58% (10 119) younger (<65 years old) and 42% (7357) elderly (≥65 years old) patients. The hazard ratio (HR) for OS was 0.77 [95% confidence interval (CI) 0.70-0.85] and 0.77 (95% CI 0.70-0.85) in the younger and elderly groups, respectively, suggesting similar efficacies of ICIs in these two age groups. The subgroup analyses revealed no significant relationship between age and treatment outcomes, except for the PFS benefit in younger patients with melanoma than in elderly patients (HR 0.44 in younger patients versus 0.65 in elderly patients, P = 0.04). These results were further supported by meta-regression analysis, which showed no statistically significant difference in OS (P = 0.954) and PFS (P = 0.555) between the two age groups. CONCLUSIONS: The findings suggest that age-associated impairments of the immune system did not affect the efficacy of ICIs in elderly patients compared to younger patients. Therefore, the choice of ICIs for elderly patients can be considered, regardless of chronological age.

Effect of an isolation-coping programme on patients isolated for colonization or infection with multi-drug-resistant organisms: a quasi-experimental study.

BACKGROUND: The global increase in the prevalence of vancomycin-resistant enterococci (VRE) and carbapenem-resistant Enterobacterales (CRE) among multi-drug-resistant organisms (MDROs) has necessitated contact precaution and isolation in medical institutions. Contact isolation has a negative effect on the mental health of patients, but few interventions have addressed this issue. AIM: To evaluate an isolation-coping programme delivered by an infection control nurse for patients colonized or infected with VRE or CRE. METHODS: An isolation-coping programme was developed to mitigate the negative effects of isolation due to MDROs, and the effects of the programme on uncertainty, anxiety, depression and knowledge of patients isolated because of MDROs (VRE or CRE) were validated using a pre-post quasi-experimental design. FINDINGS: The experimental group (N=56) received education and emotional support via the isolation-coping programme, and the control group (M=55) received verbal isolation guidelines alone from the medical institution. Compared with the control group, the experimental group showed a reduction in uncertainty (t=-8.925), anxiety (Z=-6.131) and depression (Z=-5.379), and better knowledge (Z=-8.372) (P<0.001 for all). CONCLUSION: This novel isolation-coping programme delivered by an infection control nurse was found to be an effective intervention to improve uncertainty, anxiety, depression and knowledge in patients isolated with VRE or CRE.

Systemic CXCL10 is a predictive biomarker of vitiligo lesional skin infiltration, PUVA, NB-UVB and corticosteroid treatment response and outcome.

Vitiligo is an acquired pigmentary skin disorder that currently lacks standardized treatment and validated biomarkers to objectively evaluate disease state or therapeutic response. Although prior studies have linked vitiligo autoimmunity with CXCL10/CXCL9-mediated recruitment of leukocytes to the skin, only limited clinical data are available regarding CXCL10 as vitiligo biomarker. To evaluate the utility of systemic CXCL10 as a predictor of disease progression and treatment response on a large cohort of vitiligo patients. CXCL10 levels in lesional, perilesional, and unaffected skin of vitiligo patient (n = 30) and in the serum (n = 51) were measured by quantitative ELISA. CXCL10 expression, recruitment of leukocytes, and inflammatory infiltrates were evaluated by histochemical (n = 32) and immunofluorescence (n = 10) staining. Rigorous cross-sectional and longitudinal biostatistical analysis were employed to correlate CXCL10 levels with disease variables, treatment response, and outcome. We demonstrated that elevated CXCL10 level (2 pg/mm2 and higher) in lesional skin correlates with increased leukocytic infiltrate, disease duration (< 2 year), and its higher level in the serum (50 pg/ml and higher). Changes in CXCL10 serum levels in patients treated with psoralen plus UVA (PUVA) phototherapy, narrowband UVB (NB-UVB) phototherapy, and systemic steroids (SS) correlated with changes in the intralesional CXCL10 levels in repigmented skin. NB-UVB and SS regimens provided most consistent CXCL10 mean change, suggesting that these regimens are most effective in harnessing CXCR3-mediated inflammatory response. Serum CXCL10 is a useful vitiligo biomarker, which predicts lesional skin leukocytic infiltration, and vitiligo treatment response and outcome.

Infusion of ex-vivo expanded human TCR-αß+ double-negative regulatory T cells delays onset of xenogeneic graft-versus-host disease.

Despite the demonstration of potent immunosuppressive function of T cell receptor (TCR)-αß+ double-negative regulatory T cells (DN Tregs ), scarce numbers and lack of effective expansion method limit their clinical applications. Here we describe an approach that allows for ∼3500-fold ex-vivo expansion of human DN Tregs within 3 weeks with > 97% purity. Ex-vivo-expanded DN Tregs suppress proliferation of polyclonally stimulated autologous T and B cells in vitro through direct cell-to-cell contact. In vivo, we demonstrate for the first time that infusion of human DN Tregs delayed an onset of xenogeneic graft-versus-host disease (GVHD) significantly in a humanized mouse model. Furthermore, preincubation of ex-vivo-expanded DN Tregs with a mechanistic target of rapamycin (mTOR) inhibitor rapamycin enhanced their immune regulatory function further. Taken together, this study demonstrates that human DN Tregs can be expanded ex vivo to therapeutic numbers. The expanded DN Tregs can suppress proliferation of T and B cells and attenuate GVHD, highlighting the potential clinical use of DN Tregs to mitigate GVHD.

Reversibility of atrophic gastritis and intestinal metaplasia after Helicobacter pylori eradication - a prospective study for up to 10 years.

BACKGROUND: Atrophic gastritis and intestinal metaplasia are premalignant conditions for gastric cancer. Their reversibility by Helicobacter pylori eradication remains controversial. AIM: To evaluate the reversibility of atrophic gastritis and intestinal metaplasia by H. pylori eradication with long-term follow-up. METHODS: 598 subjects were prospectively enrolled and followed for up to 10 years. They were categorised as H. pylori-negative (n = 65), H. pylori non-eradicated (n = 91), and H. pylori-eradicated (n = 442). Histological assessment was performed for antrum and corpus by Sydney classification. RESULTS: Histological follow-up was performed regularly at 1, 2, 3-4 and ≥5 years, with mean follow-up of 1.07 ± 0.21, 2.29 ± 0.83, 3.93 ± 1.02, and 6.45 ± 1.28 years, respectively. Atrophic gastritis in antrum and corpus gradually and significantly (both P < .05 for all timepoints) improved only in the H. pylori-eradicated group compared to that at baseline. Significant difference in atrophic gastritis between H. pylori-eradicated and H. pylori-negative groups disappeared from 1-year follow-up. Similarly, intestinal metaplasia in antrum and corpus improved significantly (both P < .05 for all timepoints) only in the H. pylori-eradicated group in comparison with that at baseline. Significant difference in intestinal metaplasia between H. pylori-eradicated and H. pylori-negative groups disappeared from ≥5 years of follow-up in the antrum and from 3 years of follow-up in the corpus. CONCLUSION: H. pylori eradication may be a preventative strategy for intestinal-type gastric cancer by regression of atrophic gastritis and intestinal metaplasia.

Error rate of automated calculation for wound surface area using a digital photography.

BACKGROUND: Although measuring would size using digital photography is a quick and simple method to evaluate the skin wound, the possible compatibility of it has not been fully validated. PURPOSE: To investigate the error rate of our newly developed wound surface area calculation using digital photography. METHODS: Using a smartphone and a digital single lens reflex (DSLR) camera, four photographs of various sized wounds (diameter: 0.5-3.5 cm) were taken from the facial skin model in company with color patches. The quantitative values of wound areas were automatically calculated. The relative error (RE) of this method with regard to wound sizes and types of camera was analyzed. RESULTS: RE of individual calculated area was from 0.0329% (DSLR, diameter 1.0 cm) to 23.7166% (smartphone, diameter 2.0 cm). In spite of the correction of lens curvature, smartphone has significantly higher error rate than DSLR camera (3.9431±2.9772 vs 8.1303±4.8236). However, in cases of wound diameter below than 3 cm, REs of average values of four photographs were below than 5%. In addition, there was no difference in the average value of wound area taken by smartphone and DSLR camera in those cases. CONCLUSION: For the follow-up of small skin defect (diameter: <3 cm), our newly developed automated wound area calculation method is able to be applied to the plenty of photographs, and the average values of them are a relatively useful index of wound healing with acceptable error rate.

Rapid Communication: High-resolution quantitative trait loci analysis identifies LTBP2 encoding latent transforming growth factor beta binding protein 2 associated with thoracic vertebrae number in a large F2 intercross between Landrace and Korean native pigs.

Number of vertebrae is associated with body size and meat productivity in pigs. The aim of this study was to identify QTL and associated positional candidate genes affecting the number of thoracic vertebrae (THO). A genomewide association study was conducted in a large resource population derived from an F intercross between Landrace and Korean native pigs using the Porcine SNP 60K BeadChip and the genomewide complex trait analysis (GCTA) program based on a linear mixed-effects model. A total of 38,385 SNP markers from 1,105 F progeny were analyzed for the THO trait after filtering for quality control. A total of 90 genomewide significant SNP markers ( < 1.30 × 10) on SSC 7 covering a 20-Mb region were identified for THO in this study. Several previous studies also mapped QTL for vertebral numbers in this region. The strongest association signals were detected at ASGA0035500 (-value = 4.46 × 10; 103,574,383 bp) and DIAS0000795 (-value = 4.46 × 10; 103,594,753 bp). The QTL region on SSC 7 for THO encompasses and , which are previously described candidate genes for vertebral number variation. To refine the QTL region, a haplotype-based linkage and linkage disequilibrium (LALD) analysis using the DualPHASE program was applied because subsequent conditional association and haplotype block analyses could not resolve the region that contains the 2 loci. The LALD analysis refined the critical region to a 533.9-kb region including ; was located outside the critical region. The gene encoding latent transforming growth factor beta binding protein 2 is involved in bone metabolisms. Based on these data, we propose as a positional candidate gene for THO in pigs. After further functional studies and verification of the association in other independent populations, these results could be useful for optimizing breeding programs that improve THO and other economically important traits in pigs.

Telomerase-specific oncolytic adenovirus expressing TRAIL suppresses peritoneal dissemination of gastric cancer.

Peritoneal dissemination is the most common condition of metastasis in gastric cancer. The survival duration of a patient with advanced stage gastric cancer, may be improved by gene therapy. In this study, we used an oncolytic adenovirus vector (Ad/TRAIL-E1) that expresses both the TRAIL and E1A genes under the control of a tumor-specific promoter. We evaluated the anti-tumor effect of Ad/TRAIL-E1 on gastric cancer cells in vitro, as well as in vivo in a xenograft peritoneal carcinomatosis mouse model. Our data showed that Ad/TRAIL-E1 induced TRAIL-mediated apoptosis in gastric cancer cell lines, but not in the normal cell lines. In addition, Ad/TRAIL-E1 significantly inhibited peritoneal metastasis and prolonged the survival of mice without treatment-related toxicity. Therefore, tumor-specific TRAIL expression from an oncolytic adenovirus vector may provide a novel therapeutic approach for the treatment of advance stage gastric cancer with peritoneal dissemination.

Skin photorejuvenation effects of light-emitting diodes (LEDs): a comparative study of yellow and red LEDs in vitro and in vivo.

BACKGROUND: Red-coloured light-emitting diodes (LEDs) can improve skin photorejuvenation and regeneration by increasing cellular metabolic activity. AIM: To evaluate the effectiveness of visible LEDs with specific wavelengths for skin photorejuvenation in vitro and in vivo. METHODS: Normal human dermal fibroblasts (HDFs) from neonatal foreskin were cultured and irradiated in vitro by LEDs at different wavelengths (410-850 nm) and doses (0-10 J/cm(2) ). In vivo experiments were performed on the skin of hairless mice. Expression of collagen (COL) and matrix metalloproteinases (MMPs) was evaluated by semi-quantitative reverse transcription PCR (semi-qRT-PCR), western blotting and a procollagen type I C-peptide enzyme immunoassay (EIA). Haematoxylin and eosin and Masson trichrome stains were performed to evaluate histological changes. RESULTS: In HDFs, COL I was upregulated and MMP-1 was downregulated in response to LED irradiation at 595 ± 2 and 630 ± 8 nm. In the EIA, a peak result was achieved at a dose of 5 J/cm(2) with LED at 595 ± 2 nm. In vivo, COL I synthesis was upregulated in a dose-dependent manner to both 595 and 630 nm LED irradiation, and this effect was prolonged to 21 days after a single irradiation with a dose of 100 J/cm(2) . These histological changes were consistent with the results of semi-qRT-PCR and western blots. CONCLUSION: Specific LED treatment with 595 ± 2 and 630 ± 8 nm irradiation was able to modulate COL and MMPs in skin, with the effects persisting for at least 21 days after irradiation. These findings suggest that yellow and red LEDs might be useful tools for skin photorejuvenation.

Lymph node size is not a reliable criterion for predicting nodal metastasis in rectal neuroendocrine tumours.

AIM: The study was designed to assess the correlation between lymph node (LN) size and LN metastasis in patients with rectal neuroendocrine tumours (NETs). METHOD: Forty patients who underwent curative resection with lymphadenectomy for a rectal NET between January 2007 and December 2012 were included. The short and long diameters of entire nodes were microscopically measured using a slide gauge. RESULTS: In all, 1052 LNs were collected from the 40 patients, with 49 (4.7%) showing evidence of metastasis. Metastasis-positive LNs had significantly greater long and short diameters (P < 0.001) than metastasis-negative LNs. Of the 49 metastatic LNs, 29 (59.2%) were ≤ 5 mm in largest diameter. In five patients, the largest metastatic LN was only 2-3 mm in diameter. In clinically node-negative (cN0) patients, 18 (51.4%) patients had metastatic LNs (pN1). CONCLUSION: The size of LNs containing metastasis varied widely, with some being very small. LN size alone is therefore not a sufficient predictor of tumour metastasis in rectal NETs. Radical surgery with lymphadenectomy should be considered for patients with rectal NETs with high risk factors for LN metastasis, even those without LN enlargement.

Absorption of impinging water droplet in porous stones.

This paper presents an experimental investigation and numerical analysis of the absorption of water droplets impacting porous stones. The absorption process of an impinging droplet is here fully characterized from spreading to evaporation in terms of absorbed mass during droplet depletion and moisture content distribution in a time-resolved manner for three different natural stones. High-speed imaging and neutron radiography are used to quantify moisture absorption in porous stones of varying moisture properties from deposition until depletion. During impact and spreading, the droplet exhibits a dynamic non-wetting behavior. At maximum spreading, the droplet undergoes pinning, resulting into the contact radius remaining constant until droplet depletion. Absorption undergoes two phases: initially, absorption is hindered due a contact resistance attributed to entrapped air; afterwards, a more perfect capillary contact occurs and absorption goes on until depletion, concurrently with evaporation and further redistribution. A finite-element numerical model for isothermal unsaturated moisture transport in porous media captures the phases of mass absorption in good agreement with the experimental data. Droplet spreading and absorption are highly determined by the impact velocity of the droplet, while moisture content redistribution after depletion is much less dependent on impact conditions.

Drop impact on natural porous stones.

Drop impact and spreading on three natural porous stones are experimentally determined using high-speed imaging and compared with spreading over an impermeable steel surface. The dynamic non-wetting behavior during spreading and the hydrophobic contact angle >90° is attributed to the presence of an air layer between the droplet and the porous substrate. As the contact line pins at maximum spreading on the porous stone, the maximum spreading determines the liquid contact area on such substrate. The droplet gets pinned when the air layer is broken at the contact line and capillary forces develop in fines pores at the droplet edge, pinning the droplet. Maximum spreading on porous stones increases with impact velocity but does not scale with Weber number at low impact velocity. It is demonstrated that dynamic wetting plays an important role in the spreading at low velocity and that the dynamic wetting as characterized by the dynamic contact angle θD has to be taken into account for predicting the maximum spreading. Correcting the maximum spreading ratio with the dynamic wetting behavior, all data for porous stones and non-porous substrate collapse onto a single curve.

Optimization of electrospun fibrous membranes for in vitro modeling of blood-brain barrier.

The blood-brain barrier (BBB) plays a critical role in brain homeostasis at the cellular and global level. Mimicking the selective permeability and transport properties of the BBB to specific molecules and cells remains a significant challenge towards the development of a physiologically relevant in vitro BBB model. In this study, we developed electrospun poly (ε-caprolactone) (PCL) and polyethylene glycol (PEG) copolymer membranes that supported different cellular components of the neurovascular unit including human-derived endothelial cells, pericytes and astrocytes. Comparative analyses of thickness, morphology, biocompatibility and permeability of membranes were also conducted. We found that collagen coated 4%PEG-96%PCL membranes supported the growth of a confluent and tight endothelium confirmed by transendothelial electrical resistance measurements (TEER). Based on fabrication process and reported results, we finally discuss the adoption of these electrospun fiber membranes for in vitro and on-a-chip human BBB models.

Reconstruction algorithm for nasal basal cell carcinoma with skin involvement only: analysis of 221 cases repaired by minor surgery.

BACKGROUND: Basal cell carcinoma (BCC) often occurs on the nose. Reconstruction of the nose should yield excellent aesthetic and functional outcomes. AIM: We propose a technical algorithm for the reconstruction of surgical defects, based on our analysis of 221 cases of nasal BCC with skin involvement only, which could be repaired by minor surgery. METHODS: The aesthetic and functional outcomes for various reconstruction techniques were analysed according to defect location and size. A reconstruction algorithm was proposed with the aim of obtaining the best surgical results. RESULTS: Defect location and size were key considerations. Primary closure was the first option for small defects (< 10 mm), with scores of 3.4 for objective aesthetic outcome (OAO), 3.2 for subjective aesthetic outcome (SAO) and 3.3 for subjective functional outcome (SFO). The first option for medium defects (1-20 mm) was the island pedicle flap, with scores of 3.5 for OAO, 3.2 for SAO and 3.7 for SFO. The first option for large defects (> 20 mm) was the transposition flap for the upper nose (scores of 2.0 for OAO and SAO and 3.0 for SFO) and the interpolation flap for the lower nose (2.8 for OAO and 2.9 for SAO and SFO). CONCLUSIONS: We have proposed an algorithm to select the optimal technique for repairing nasal BCC surgical defects according to their size and location.

Role of confirmatory interferon-gamma release assays in school outbreaks of tuberculosis in South Korea.

OBJECTIVE: To investigate the usefulness of confirmatory QuantiFERON(®) (QFT) testing among tuberculin skin test (TST) positive contacts to diagnose latent tuberculous infection (LTBI) in tuberculosis (TB) outbreaks among adolescents. DESIGN: We used the Korean national claims database to identify the development of active TB disease in relation to initial TST (cut-off 10 mm induration) and subsequent QFT results. RESULTS: A total of 7475 contacts in 89 schools were divided into four groups: TST- (n = 5714), TST+/QFT+ (n = 534), TST+/QFT- (n = 697) and TST+ only (n = 530). The mean duration of follow-up was 3.9 ± 0.9 years. For contacts with no LTBI treatment (n = 6868), TB incidence rates per 1000 person-years (py) and the adjusted hazard ratio (HR) compared with TST- individuals were as follows: TST+/QFT+, 66.2/1000 py (HR 35.59, 95%CI 14.03-90.31, P < 0.001); TST+ only, 10.1/1000 py (HR 5.16, 95%CI 2.91-9.17, P < 0.001); TST+/QFT-, 4.0/1000 py (HR 2.05, 95%CI 1.05-4.01, P = 0.035); and TST- 2.0/1000 py. The TB progression rate was significantly higher in TST+/QFT+ than in TST+/QFT- individuals (HR 16.82, 95 CI 5.84-48.46, P < 0.001). CONCLUSION: A confirmatory QFT for TST+ contacts could reduce the number of candidates for LTBI treatment after school TB outbreaks.