Local-scale phylodynamics reveal differential community impact of SARS-CoV-2 in a metropolitan US county.

SARS-CoV-2 transmission is largely driven by heterogeneous dynamics at a local scale, leaving local health departments to design interventions with limited information. We analyzed SARS-CoV-2 genomes sampled between February 2020 and March 2022 jointly with epidemiological and cell phone mobility data to investigate fine scale spatiotemporal SARS-CoV-2 transmission dynamics in King County, Washington, a diverse, metropolitan US county. We applied an approximate structured coalescent approach to model transmission within and between North King County and South King County alongside the rate of outside introductions into the county. Our phylodynamic analyses reveal that following stay-at-home orders, the epidemic trajectories of North and South King County began to diverge. We find that South King County consistently had more reported and estimated cases, COVID-19 hospitalizations, and longer persistence of local viral transmission when compared to North King County, where viral importations from outside drove a larger proportion of new cases. Using mobility and demographic data, we also find that South King County experienced a more modest and less sustained reduction in mobility following stay-at-home orders than North King County, while also bearing more socioeconomic inequities that might contribute to a disproportionate burden of SARS-CoV-2 transmission. Overall, our findings suggest a role for local-scale phylodynamics in understanding the heterogeneous transmission landscape.

Convergence of immune escape strategies highlights plasticity of SARS-CoV-2 spike.

The global spread of the SARS-CoV-2 virus has resulted in emergence of lineages which impact the effectiveness of immunotherapies and vaccines that are based on the early Wuhan isolate. All currently approved vaccines employ the spike protein S, as it is the target for neutralizing antibodies. Here we describe two SARS-CoV-2 isolates with unusually large deletions in the N-terminal domain (NTD) of the spike. Cryo-EM structural analysis shows that the deletions result in complete reshaping of the NTD supersite, an antigenically important region of the NTD. For both spike variants the remodeling of the NTD negatively affects binding of all tested NTD-specific antibodies in and outside of the NTD supersite. For one of the variants, we observed a P9L mediated shift of the signal peptide cleavage site resulting in the loss of a disulfide-bridge; a unique escape mechanism with high antigenic impact. Although the observed deletions and disulfide mutations are rare, similar modifications have become independently established in several other lineages, indicating a possibility to become more dominant in the future. The observed plasticity of the NTD foreshadows its broad potential for immune escape with the continued spread of SARS-CoV-2.

Genomic Epidemiology of Treponema pallidum and Circulation of Strains With Diminished tprK Antigen Variation Capability in Seattle, 2021-2022.

BACKGROUND: The incidence of syphilis continues to increase in the United States, yet little is known about Treponema pallidum genomic epidemiology within American metropolitan areas. METHODS: We performed whole-genome sequencing and tprK deep sequencing of 28 T. pallidum-containing specimens, collected mostly from remnant Aptima swab specimens from 24 individuals from Seattle Sexual Health Clinic during 2021-2022. RESULTS: All 12 individuals infected with Nichols-lineage strains were men who have sex with men, while a specific SS14 cluster (mean, 0.33 single-nucleotide variant) included 1 man who has sex with women and 5 women. All T. pallidum strains sequenced were azithromycin resistant via 23S ribosomal RNA A2058G mutation. Identical T. pallidum genomic sequences were found in pharyngeal and rectal swab specimens taken concurrently from the same individuals. The tprK sequences were less variable between patient-matched specimens and between epidemiologically linked clusters. We detected a 528-base pair deletion in the tprK donor site locus, eliminating 9 donor sites, in T. pallidum genomes of 3 individuals with secondary syphilis, associated with diminution of TprK diversity. CONCLUSIONS: We developed an end-to-end workflow for public health genomic surveillance of T. pallidum from remnant Aptima swab specimens. tprK sequencing may assist in linking cases beyond routine T. pallidum genome sequencing. T. pallidum strains with deletions in tprK donor sites currently circulate and are associated with diminished TprK antigenic diversity.

Harnessing the potential of data-driven strategies to optimise transfusion practice.

No one doubts the significant variation in the practice of transfusion medicine. Common examples are the variability in transfusion thresholds and the use of tranexamic acid for surgery with likely high blood loss despite evidence-based standards. There is a long history of applying different strategies to address this variation, including education, clinical guidelines, audit and feedback, but the effectiveness and cost-effectiveness of these initiatives remains unclear. Advances in computerised decision support systems and the application of novel electronic capabilities offer alternative approaches to improving transfusion practice. In England, the National Institute for Health and Care Research funded a Blood and Transplant Research Unit (BTRU) programme focussing on 'A data-enabled programme of research to improve transfusion practices'. The overarching aim of the BTRU is to accelerate the development of data-driven methods to optimise the use of blood and transfusion alternatives, and to integrate them within routine practice to improve patient outcomes. One particular area of focus is implementation science to address variation in practice.

Distinct clinical trajectories of gastrointestinal progression among patients with systemic sclerosis.

OBJECTIVES: Systemic sclerosis (SSc) is heterogeneous in its clinical presentation. Common manifestations cluster together, defining unique subgroups. This investigation aims to characterize gastrointestinal (GI) phenotypes and determine whether they can be distinguished by temporal progression. METHODS: We examine a well-established SSc patient cohort with a modified Medsger GI severity score measured over time to determine heterogeneity in disease progression. Growth mixture models estimate each patient's phenotype and disease severity trajectory over time. We compare the characteristics of estimated phenotypes using non-parametric statistics and linear and logistic regression to compare patient characteristics between phenotypes while adjusting for disease duration. RESULTS: We examined 2696 SSc patients with at least two Medsger GI scores, identifying four unique phenotypes. The most common phenotype (n = 2325) ("Stable") had an average score of 1 that was consistent over time. Two phenotypes were progressive ["Early Progressive" (n = 142) and "Late Progressive" (n = 115)] with an initial average score of 1. The Early Progressive group increased initially and stabilized, and the Late Progressive group worsened slowly over time. A fourth phenotype ["Early Severe GI"; (n = 114)] had an initial average Medsger GI score just below 3 with high mortality and improving GI severity over time. CONCLUSIONS: Clinically distinct GI phenotypes exist among patients with SSc. These phenotypes are not only distinguished by GI and extra-intestinal SSc clinical complications, but they are also temporally distinct. Distinct autoantibody profiles are associated strongly with more severe GI disease.

Elevated Electron Temperature Coincident with Observed Fusion Reactions in a Sheared-Flow-Stabilized Z Pinch.

The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially and temporally coincident with the plasma neutron source. An optical Thomson scattering apparatus designed for the FuZE device measures temperatures in the range of 1-3 keV on the axis of the device, 20 cm downstream of the nose cone. The 17-fiber system measures the radial profiles of the electron temperature. Scanning the laser time with respect to the neutron pulse time over a series of discharges allows the reconstruction of the T_{e} temporal response, confirming that the electron temperature peaks simultaneously with the neutron output, as well as the pinch current and inductive voltage generated within the plasma. Comparison to spectroscopic ion temperature measurements suggests a plasma in thermal equilibrium. The elevated T_{e} confirms the presence of a plasma assembled on axis, and indicates limited radiative losses, demonstrating a basis for scaling this device toward net gain fusion conditions.

The bright Easter bunny sign: a useful aide-memoire on MRI for costotransverse joint inflammation in axial spondyloarthritis.

AIM: To assess the significance of the "bright Easter bunny" sign on magnetic resonance imaging (MRI) to indicate inflammatory costotransverse joint (CtJ) lesions to diagnose axial spondyloarthritis (ax-SpA). MATERIALS AND METHODS: Consecutive cases of patients with ax-SpA from a specialist rheumatology clinic were analysed retrospectively over two cohorts, between 2012-2014 and 2018-2020, to determine newly diagnosed patients under the Assessment of SpondyloArthritis international Society (ASAS) criteria. Biological naive adult patients who underwent spine MRI and sacroiliac imaging with full immunological work-up and a C-reactive protein reading within 3 months of the scan were included. Blinded images were reviewed by experienced musculoskeletal radiologists. RESULT: From the 1,284 cases that were identified, 40 cases met the inclusion criteria for this study. Seven out of the 40 cases (17.5%) identified inflammatory lesions at the CtJ with five (70%) showing concordance with the bright Easter bunny sign. CONCLUSION: The bright Easter bunny sign is concordant with inflammatory costotransverse enthesitis. This aide-memoire radiological sign is often on overlooked edge-of-field sections and this emphasises the need to ensure adequate coverage of the CtJ on spine MRI protocols as an important anatomical site of inflammatory change in ax-SpA assessment.

Unveiling the spiral groove: a journey through clinical anatomy, pathology, and imaging.

AIM: To review the anatomy of the spiral groove, its clinical significance, and the imaging characteristics of common pathologies affecting this area, highlighting the strengths of different imaging modalities. MATERIALS AND METHODS: A comprehensive review of the spiral groove anatomy and its clinical implications and an evaluation of various imaging techniques, including radiography, ultrasound, MRI, and CT, was conducted. The review covers pathologic conditions such as Saturday night palsy, humeral fractures, tumours, and infections, with an emphasis on their imaging findings and clinical implications. RESULTS: The spiral groove provides a pathway for the radial nerve and the deep brachial artery, both crucial for upper limb function. Each imaging modality offers unique advantages: radiography is useful for initial assessment, ultrasound provides dynamic visualisation, MRI offers high-resolution soft tissue imaging, and CT is ideal for detailed bone anatomy. Understanding these imaging characteristics is essential for diagnosing fractures, assessing humeral alignment, and detecting nerve entrapment or injury. CONCLUSION: Accurate imaging of the spiral groove is essential for diagnosing and treating pathologies related to this anatomical feature. The integrative approach of using appropriate imaging modalities enhances diagnostic precision and informs therapeutic strategies, ultimately improving patient outcomes.

Feasibility, Safety and Acceptance of Buccal Mucosa Harvest Under Local Anesthesia for Substitution Urethroplasty:Prospective Observational Study in a Tertiary Centre.

Background Urethral stricture is a challenging condition with significant socioeconomic impacts, often requiring surgical intervention such as urethroplasty. Buccal mucosa grafts (BMG) are a popular choice for substitution urethroplasty due to their favorable outcomes. This study evaluates the feasibility, safety, and acceptance of harvesting buccal mucosa grafts under local anesthesia. Objective To assess feasibility, safety and acceptance of Buccal mucosa harvest under local anesthesia. Method A prospective observational hospital based study to evaluate outcomes of substitution urethroplasty using buccal mucosa grafts (BMG) under local anesthesia. Result Of the 40 patients, 28 had unilateral graft harvests, while 12 had bilateral procedures. The mean graft length obtained was 5.65 cm. Postoperatively, patients experienced a quick recovery, with full mouth opening achieved within an average of 2.78 days and resumption of normal eating within 2.6 days. Minor complications included oral swelling in 15% of cases and food residue in 12.5%. Although 87.5% of patients reported pain at the perineal wound site, the overall pain score averaged 3.58, indicating manageable discomfort. Importantly, 92.5% of patients expressed a willingness to undergo the procedure again if necessary. Conclusion These findings suggest that buccal mucosa graft harvest under local anesthesia is both feasible and well-tolerated. The procedure appears to be a safe alternative to regional or general anesthesia, with minimal complications and a high level of patient acceptance. Future randomized controlled trials comparing local anesthesia to regional or general anesthesia could provide additional insights and further validate these findings. This study contributes to the growing body of evidence supporting the use of local anesthesia in urethral stricture surgery, offering a practical approach to managing this condition effectively.

Genomic Characterization of Respiratory Syncytial Virus during 2022-23 Outbreak, Washington, USA.

We sequenced 54 respiratory syncytial virus (RSV) genomes collected during 2021-22 and 2022-23 outbreaks in Washington, USA, to determine the origin of increased RSV cases. Detected RSV strains have been spreading for >10 years, suggesting a role for diminished population immunity from low RSV exposure during the COVID-19 pandemic.

The Capture the Fracture® Partnership: an overview of a global initiative to increase the secondary fracture prevention care for patient benefit.

The Capture the Fracture® Partnership (CTF-P) is a unique collaboration between the International Osteoporosis Foundation, academic units and industry partners to enhance the implementation of effective, efficient fracture liaison services (FLSs) with a good patient experience. CTF-P has generated valuable resources for the specific countries as well as the broader FLS community to improve the initiation, effectiveness and sustainability of FLS in a wide range of healthcare settings.

Prediction of postnatal circulation in pulmonary atresia/critical stenosis with intact ventricular septum: systematic review and external validation of models.

OBJECTIVE: A favorable postnatal prognosis in cases of pulmonary atresia/critical stenosis with intact ventricular septum (PA/CS-IVS) is generally equated with the possibility of achieving biventricular (BV) repair. Identification of fetuses that will have postnatal univentricular (UV) circulation is key for prenatal counseling, optimization of perinatal care and decision-making regarding fetal therapy. We aimed to evaluate the accuracy of published models for predicting postnatal circulation in PA/CS-IVS using a large internationally derived validation cohort. METHODS: This was a systematic review of published uni- and multiparametric models for the prediction of postnatal circulation based on echocardiographic findings at between 20 and 28 weeks of gestation. Models were externally validated using data from the International Fetal Cardiac Intervention Registry. Sensitivity, specificity, predictive values, area under the receiver-operating-characteristics curves (AUCs) and proportion of cases with true vs predicted outcome were calculated. RESULTS: Eleven published studies that reported prognostic parameters of postnatal circulation were identified. Models varied widely in terms of the main outcome (UV (n = 3), non-BV (n = 3), BV (n = 3), right-ventricle-dependent coronary circulation (n = 1) or tricuspid valve size at birth (n = 1)) and in terms of the included predictors (single parameters only (n = 6), multiparametric score (n = 4) or both (n = 1)), and were developed on small sample sizes (range, 15-38). Nine models were validated externally given the availability of the required parameters in the validation cohort. Tricuspid valve diameter Z-score, tricuspid regurgitation, ratios between right and left cardiac structures and the presence of ventriculocoronary connections (VCC) were the most commonly evaluated parameters. Multiparametric models including up to four variables (ratios between right and left structures, right ventricular inflow duration, presence of VCC and tricuspid regurgitation) had the best performance (AUC, 0.80-0.89). Overall, the risk of UV outcome was underestimated and that of BV outcome was overestimated by most models. CONCLUSIONS: Current prenatal models for the prediction of postnatal outcome in PA/CS-IVS are heterogeneous. Multiparametric models for predicting UV and non-BV circulation perform well in identifying BV patients but have low sensitivity, underestimating the rate of fetuses that will ultimately have UV circulation. Until better discrimination can be achieved, fetal interventions may need to be limited to only those cases in which non-BV postnatal circulation is certain. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Major haemorrhage: past, present and future.

Major haemorrhage is a leading cause of morbidity and mortality worldwide. Successful treatment requires early recognition, planned responses, readily available resources (such as blood products) and rapid access to surgery or interventional radiology. Major haemorrhage is often accompanied by volume loss, haemodilution, acidaemia, hypothermia and coagulopathy (factor consumption and fibrinolysis). Management of major haemorrhage over the past decade has evolved to now deliver a 'package' of haemostatic resuscitation including: surgical or radiological control of bleeding; regular monitoring of haemostasis; advanced critical care support; and avoidance of the lethal triad of hypothermia, acidaemia and coagulopathy. Recent trial data advocate for a more personalised approach depending on the clinical scenario. Fresh frozen plasma should be given as early as possible in major trauma in a 1:1 ratio with red blood cells until the results of coagulation tests are available. Tranexamic acid is a cheap, life-saving drug and is advocated in major trauma, postpartum haemorrhage and surgery, but not in patients with gastrointestinal bleeding. Fibrinogen levels should be maintained > 2 g.l-1 in postpartum haemorrhage and > 1.5 g.l-1 in other haemorrhage. Improving outcomes after major traumatic haemorrhage is now driving research to include extending blood-product resuscitation into prehospital care.

Evaluation of antiglaucoma drug treatment awareness and patient-reported medication adherence: Determinants of glaucoma management.

Introduction: Primary open angle glaucoma (POAG) treatment is characterized by long-duration therapy, prescription variability, and non-adherence. Patient awareness toward drug treatment is crucial to ensure adherence. The present study was planned to evaluate drug treatment awareness, patient-perceived drug adherence, and prescription patterns in POAG patients. Methodology: This was a cross-sectional, single-center, questionnaire-based study conducted in the ophthalmology out patient department of a tertiary care hospital from April 2020 to November 2021. Patients of either gender, aged 40-70 years, with a confirmed diagnosis of POAG, who had records of POAG medications for at least last 3 months and who provided written informed consent, were included. Prescription details were recorded, and subsequently, patients were administered a pre-validated drug treatment awareness (14 items) questionnaire, a self-reported medication adherence (9-item) questionnaire, and then they performed eye drop instillation in a simulated setting. Results: The total number of patients enrolled was 180, which yielded 200 prescriptions. The mean drug treatment awareness score was 8.18 ± 3.30, and 135 (75%) patients scored more than 50% (≥7/14). Similarly, 159 patients (83.33%) had scored >50% (i.e. >5/9), with a mean score of 6.30 ± 1.70 in the medication treatment adherence questionnaire. The mean eye drop instillation performance score was 7.18 ± 1.20. The 200 POAG prescriptions containing 306 drugs were analyzed, with beta blockers (184/200, 92%) and timolol (168/200, 84% encounters) being the highest prescribed classes/drugs. Conclusion: POAG patients did have adequate treatment awareness with good self-reported medication adherence and performance of eye drop instillation technique. Around 25% patients lacked awareness; hence, reinforcement education programs on medication regimens need to be implemented.

Retrospective Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Symptomatic Patients Prior to Widespread Diagnostic Testing in Southern California.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused one of the worst pandemics in recent history. Few reports have revealed that SARS-CoV-2 was spreading in the United States as early as the end of January. In this study, we aimed to determine if SARS-CoV-2 had been circulating in the Los Angeles (LA) area at a time when access to diagnostic testing for coronavirus disease 2019 (COVID-19) was severely limited. METHODS: We used a pooling strategy to look for SARS-CoV-2 in remnant respiratory samples submitted for regular respiratory pathogen testing from symptomatic patients from November 2019 to early March 2020. We then performed sequencing on the positive samples. RESULTS: We detected SARS-CoV-2 in 7 specimens from 6 patients, dating back to mid-January. The earliest positive patient, with a sample collected on January 13, 2020 had no relevant travel history but did have a sibling with similar symptoms. Sequencing of these SARS-CoV-2 genomes revealed that the virus was introduced into the LA area from both domestic and international sources as early as January. CONCLUSIONS: We present strong evidence of community spread of SARS-CoV-2 in the LA area well before widespread diagnostic testing was being performed in early 2020. These genomic data demonstrate that SARS-CoV-2 was being introduced into Los Angeles County from both international and domestic sources in January 2020.

Variants of Concern Are Overrepresented Among Postvaccination Breakthrough Infections of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Washington State.

Across 20 vaccine breakthrough cases detected at our institution, all 20 (100%) infections were due to variants of concern (VOCs) and had a median Ct of 20.2 (IQR, 17.1-23.3). When compared with 5174 contemporaneous samples sequenced in our laboratory, VOCs were significantly enriched among breakthrough infections (P < .05).

Associations Between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants and Risk of Coronavirus Disease 2019 (COVID-19) Hospitalization Among Confirmed Cases in Washington State: A Retrospective Cohort Study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic is dominated by variant viruses; the resulting impact on disease severity remains unclear. Using a retrospective cohort study, we assessed the hospitalization risk following infection with 7 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. METHODS: Our study includes individuals with positive SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) in the Washington Disease Reporting System with available viral genome data, from 1 December 2020 to 14 January 2022. The analysis was restricted to cases with specimens collected through sentinel surveillance. Using a Cox proportional hazards model with mixed effects, we estimated hazard ratios (HR) for hospitalization risk following infection with a variant, adjusting for age, sex, calendar week, and vaccination. RESULTS: In total, 58 848 cases were sequenced through sentinel surveillance, of which 1705 (2.9%) were hospitalized due to COVID-19. Higher hospitalization risk was found for infections with Gamma (HR 3.20, 95% confidence interval [CI] 2.40-4.26), Beta (HR 2.85, 95% CI 1.56-5.23), Delta (HR 2.28 95% CI 1.56-3.34), or Alpha (HR 1.64, 95% CI 1.29-2.07) compared to infections with ancestral lineages; Omicron (HR 0.92, 95% CI .56-1.52) showed no significant difference in risk. Following Alpha, Gamma, or Delta infection, unvaccinated patients show higher hospitalization risk, while vaccinated patients show no significant difference in risk, both compared to unvaccinated, ancestral lineage cases. Hospitalization risk following Omicron infection is lower with vaccination. CONCLUSIONS: Infection with Alpha, Gamma, or Delta results in a higher hospitalization risk, with vaccination attenuating that risk. Our findings support hospital preparedness, vaccination, and genomic surveillance.

Surgical phocomelia or phoco-reduction as a method of limb salvage for sarcomas of the upper limb: A suitable alternative to amputation.

BACKGROUND: Reconstruction following resection of sarcomas of the upper extremity with methods described in the prevalent literature may not be possible in few selected cases. We describe surgical phocomelia or phoco-reduction as a method of limb salvage in such cases of extensive sarcomas of the upper limb with its functional and oncological outcomes. METHODS: Evaluation of functional and oncological outcomes was performed for 11 patients who underwent surgical phocomelia or phoco-reduction for extensive sarcomas of the upper limb between 2010 and 2019. RESULTS: The mean follow-up period in the study was 27.8 months. Five patients required a segmental resection including the entire humerus while six patients underwent segmental resection around the elbow with a mean resection length of 21.5 cm. Mean Musculoskeletal Tumor Society 93 score was 22 depicting a good functional outcome. Mean handgrip strength on the operated side was 62% of the contralateral side with preservation of useful hand function. Meantime to humeroulnar union was 6.7 months. Radial nerve palsy and implant failure occurred in one patient each. No patient developed local recurrence while three patients died of metastasis. CONCLUSION: Surgical phocomelia is a prudent alternative to severely incapacitating amputations in situations where other reconstruction methods are not feasible.

Leaving half the acetabulum in pelvic resections improves hip function. Is there a need to revisit conventional pelvic resections?

BACKGROUND: Conventional periacetabular pelvic resections are associated with poor functional outcomes. Resections through surgical corridors beyond the conventional margins may be helpful in retaining greater function without compromising the oncological margins. METHODS: The study included a retrospective review of 82 cases of pelvic resections for pelvic tumors. Outcomes of acetabulum preservation (Group A) were compared with complete acetabular resection (Group B). Also, we compared outcomes of Type I + half resections (Group 1) with Type I + II resections (Group 2), and Type III + half resections (Group 3) with Type II + III resections (Group 4). RESULTS: Group A (n = 44) had significantly better functional outcome than Group B (n = 38) with average MSTS93 score 22.3 versus 20.1 and average HHS 91.3 versus 82.5 (p < 0.001). Group 1 (n = 14) and Group 2 (n = 12) had similar functional outcomes (mean MSTS93 score 22.07 vs. 21.58 [p = 0.597] and mean HHS 90.37 vs. 86.51 [p = 0.205]). Group 3 (n = 11) had significantly better functional outcome than Group 4 (n = 17), with mean MSTS93 score 22.8 versus 19.7 (p < 0.001) and mean HHS 92.3 versus 80.1 (p < 0.001). Oncological outcomes were similar among the groups. CONCLUSION: Transacetabular pelvic resections provide functional benefit over conventional resections without compromising oncological margins. There is a need to revisit and revise the pelvic resection planes.

Compatibility of Al-doped ZnO electron transport layer with various HTLs and absorbers in perovskite solar cells.

Perovskite solar cells (PSCs) have shown a significant improvement in cell performance in photovoltaics technology. The commonly used light absorbing material of halide-based perovskite in PSCs has produced high efficiency cells with low cost and a simple fabrication process. However, it contains the harmful substance of Pb, which affects the environment, and the cell still suffers from instability in the long run. Therefore, this work presents a theoretical study of the Pb-free absorber layer of CH3NH3SnI3 that is paired for compatibility with various types of hole transport layers (HTLs). Several key parameters of the absorbent layer and HTL have been optimized to produce the highest power conversion efficiency (PCE) using 1D-SCAPS software under AM 1.5 illumination. It was found that the combination of Cu2O and CH3NH3SnI3 used as the HTL and absorbent layer, respectively, has resulted in great PCE as high as 27.72%. These findings prove that the use of inorganic HTLs and Pb-free perovskite layers is promising for use in PSCs.