The Architecture of SARS-CoV-2 Transcriptome.

SARS-CoV-2 is a betacoronavirus responsible for the COVID-19 pandemic. Although the SARS-CoV-2 genome was reported recently, its transcriptomic architecture is unknown. Utilizing two complementary sequencing techniques, we present a high-resolution map of the SARS-CoV-2 transcriptome and epitranscriptome. DNA nanoball sequencing shows that the transcriptome is highly complex owing to numerous discontinuous transcription events. In addition to the canonical genomic and 9 subgenomic RNAs, SARS-CoV-2 produces transcripts encoding unknown ORFs with fusion, deletion, and/or frameshift. Using nanopore direct RNA sequencing, we further find at least 41 RNA modification sites on viral transcripts, with the most frequent motif, AAGAA. Modified RNAs have shorter poly(A) tails than unmodified RNAs, suggesting a link between the modification and the 3' tail. Functional investigation of the unknown transcripts and RNA modifications discovered in this study will open new directions to our understanding of the life cycle and pathogenicity of SARS-CoV-2.

The Association Between Antibody Responses and Prolonged Viable Severe Acute Respiratory Syndrome Coronavirus 2 Shedding in Immunocompromised Patients: A Prospective Cohort Study.

Immunocompromised patients with coronavirus disease 2019 were prospectively enrolled from March to November 2022 to understand the association between antibody responses and severe acute respiratory syndrome coronavirus 2 shedding. A total of 62 patients were analyzed, and the results indicated a faster decline in genomic and subgenomic viral RNA in patients with higher neutralizing and S1-specific immunoglobulin G (IgG) antibodies (both P < .001). Notably, high neutralizing antibody levels were associated with a significantly faster decrease in viable virus cultures (P = .04). Our observations suggest the role of neutralizing antibodies in prolonged virus shedding in immunocompromised patients, highlighting the potential benefits of enhancing their humoral immune response through vaccination or monoclonal antibody treatments.

Differential beta-coronavirus infection dynamics in human bronchial epithelial organoids.

The lower respiratory system serves as the target and barrier for beta-coronavirus (beta-CoV) infections. In this study, we explored beta-CoV infection dynamics in human bronchial epithelial (HBE) organoids, focusing on HCoV-OC43, SARS-CoV, MERS-CoV, and SARS-CoV-2. Utilizing advanced organoid culture techniques, we observed robust replication for all beta-CoVs, particularly noting that SARS-CoV-2 reached peak viral RNA levels at 72 h postinfection. Through comprehensive transcriptomic analysis, we identified significant shifts in cell population dynamics, marked by an increase in goblet cells and a concurrent decrease in ciliated cells. Furthermore, our cell tropism analysis unveiled distinct preferences in viral targeting: HCoV-OC43 predominantly infected club cells, while SARS-CoV had a dual tropism for goblet and ciliated cells. In contrast, SARS-CoV-2 primarily infected ciliated cells, and MERS-CoV showed a marked affinity for goblet cells. Host factor analysis revealed the upregulation of genes encoding viral receptors and proteases. Notably, HCoV-OC43 induced the unfolded protein response pathway, which may facilitate viral replication. Our study also reveals a complex interplay between inflammatory pathways and the suppression of interferon responses during beta-CoV infections. These findings provide insights into host-virus interactions and antiviral defense mechanisms, contributing to our understanding of beta-CoV infections in the respiratory tract.

Randomized controlled trial on the efficacy of a custom-made, fully guided implant system for flapless crestal sinus floor elevation: Accuracy and patient-reported outcomes.

OBJECTIVE: To compare fully guided flapless implant surgery using a light-cured surgical guide (FG group) with partially guided open flap surgery (PG group) in the posterior maxilla when performing simultaneous sinus floor elevation in terms of the accuracy, time requirements, and patient/clinician-reported outcomes (PROMs and CROMs). MATERIALS AND METHODS: In this study, 56 tissue-level implants were placed with crestal sinus floor elevation in 56 patients at single-tooth sites, with 28 implants allocated to the PG group and 28 to the FG group. The deviations of the placed implants from the virtually planned positions were measured at the implant platform and apex and for the angular deviation. The presurgical preparation time and the duration of surgery were measured. PROMs and CROMs were made by administering questionnaires at multiple time points. RESULTS: Horizontal deviations at the platform and apex and the angular deviation were significantly smaller in the FG group than the PG group (p < .05). Presurgical preparation and surgery times were significantly shorter in the FG group (p < .001). Patient satisfaction and willingness to receive repeat treatment were significantly better in the FG group than in the PG group (p < .005 and .025, respectively). Clinicians were more satisfied in the FG group than the PG group (p < .05). CONCLUSION: When placing an implant with sinus floor elevation, the flapless approach using a fully guided surgical system can be more accurate, faster, and increase the satisfaction of both the clinician and patient compared to the partially guided surgery.

Effect of 4-week preoperative prism adaptation in preventing postoperative residual esotropia.

BACKGROUND: Preoperative prism adaptation (PPA) simulates postoperative status and possibly can predict postoperative undercorrection before surgery in esotropia. The present study aimed to assess the effect of 4-week PPA in preventing postoperative residual esotropia. METHODS: Seventy-five (75) esotropes who had undergone surgery at a single strabismus center were retrospectively enrolled. They included 25 basic, 31 acute comitant, 10 partially accommodative, and 9 recurrent esotropia patients. The preoperative deviation angle, which had been determined using the alternating prism and cover test, was fully corrected with press-on prisms 4 weeks before surgery. If there was an increase of 5 PD or more of esodeviation, the prisms were changed accordingly at 2 weeks. The deviation angle measured at 4 weeks was determined as the surgical target angle. Patients were then divided into increase (≥ 5 PD increase of angle during 4-week PPA) and non-increase groups. Success was defined as either esodeviation of 8 PD or under or exodeviation of 5 PD or under at distance at postoperative 6 months. RESULTS: The increase group included 44 patients (58.7%). The mean deviation angle before PPA was 27.4 PD, and after the 4-week PPA, there was an average increase of 9.4 PD. The success rate was 90.9% in the increase group and 96.8% in the non-increase group (p = 0.316). There were no intergroup differences in preoperative clinical characteristics, esotropia types, postoperative deviation angle or postoperative near stereopsis (p > 0.05). CONCLUSIONS: The results of this study indicated a beneficial effect of 4-week PPA in esotropia of various types, specifically by uncovering the hidden esodeviation in the increase group and simulating the postoperative alignment in both the increase and the non-increase groups.

Experimental Infection and Transmission of SARS-CoV-2 Delta and Omicron Variants among Beagle Dogs.

We assessed susceptibility of dogs to SARS-COV-2 Delta and Omicron variants by experimentally inoculating beagle dogs. Moreover, we investigated transmissibility of the variants from infected to naive dogs. The dogs were susceptible to infection without clinical signs and transmitted both strains to other dogs through direct contact.

Pericytes are protective in experimental pneumococcal meningitis through regulating leukocyte infiltration and blood-brain barrier function.

BACKGROUND: Brain pericytes participate in the regulation of cerebral blood flow and the maintenance of blood-brain barrier integrity. Because of their perivascular localization, their receptor repertoire, and their potential ability to respond to inflammatory and infectious stimuli by producing various cytokines and chemokines, these cells are also thought to play an active role in the immune response to brain infections. This assumption is mainly supported by in vitro studies, investigations in in vivo disease models are largely missing. Here, we analysed the role of brain pericytes in pneumococcal meningitis, in vitro and in vivo in two animal models of pneumococcal meningitis. METHODS: Primary murine and human pericytes were stimulated with increasing concentrations of different serotypes of Streptococcus pneumoniae in the presence or absence of Toll-like receptor inhibitors and their cell viability and cytokine production were monitored. To gain insight into the role of pericytes in brain infection in vivo, we performed studies in a zebrafish embryo model of pneumococcal meningitis in which pericytes were pharmacologically depleted. Furthermore, we analyzed the impact of genetically induced pericyte ablation on disease progression, intracranial complications, and brain inflammation in an adult mouse model of this disease. RESULTS: Both murine and human pericytes reacted to pneumococcal exposure with the release of selected cytokines. This cytokine release is pneumolysin-dependent, TLR-dependent in murine (but not human) pericytes and can be significantly increased by macrophage-derived IL-1b. Pharmacological depletion of pericytes in zebrafish embryos resulted in increased cerebral edema and mortality due to pneumococcal meningitis. Correspondingly, in an adult mouse meningitis model, a more pronounced blood-brain barrier disruption and leukocyte infiltration, resulting in an unfavorable disease course, was observed following genetic pericyte ablation. The degree of leukocyte infiltration positively correlated with an upregulation of chemokine expression in the brains of pericyte-depleted mice. CONCLUSIONS: Our findings show that pericytes play a protective role in pneumococcal meningitis by impeding leukocyte migration and preventing blood-brain barrier breaching. Thus, preserving the integrity of the pericyte population has the potential as a new therapeutic strategy in pneumococcal meningitis.

Identifying treatment heterogeneity in atrial fibrillation using a novel causal machine learning method.

BACKGROUND: Lifelong oral anticoagulation is recommended in patients with atrial fibrillation (AF) to prevent stroke. Over the last decade, multiple new oral anticoagulants (OACs) have expanded the number of treatment options for these patients. While population-level effectiveness of OACs has been compared, it is unclear if there is variability in benefit and risk across patient subgroups. METHODS: We analyzed claims and medical data for 34,569 patients who initiated a nonvitamin K antagonist oral anticoagulant (non-vitamin K antagonist oral anticoagulant (NOAC); apixaban, dabigatran, and rivaroxaban) or warfarin for nonvalvular AF between 08/01/2010 and 11/29/2017 from the OptumLabs Data Warehouse. A machine learning (ML) method was applied to match different OAC groups on several baseline variables including, age, sex, race, renal function, and CHA2DS2 -VASC score. A causal ML method was then used to discover patient subgroups characterizing the head-to-head treatment effects of the OACs on a primary composite outcome of ischemic stroke, intracranial hemorrhage, and all-cause mortality. RESULTS: The mean age, number of females and white race in the entire cohort of 34,569 patients were 71.2 (SD, 10.7) years, 14,916 (43.1%), and 25,051 (72.5%) respectively. During a mean follow-up of 8.3 (SD, 9.0) months, 2,110 (6.1%) of patients experienced the composite outcome, of whom 1,675 (4.8%) died. The causal ML method identified 5 subgroups with variables favoring apixaban over dabigatran; 2 subgroups favoring apixaban over rivaroxaban; 1 subgroup favoring dabigatran over rivaroxaban; and 1 subgroup favoring rivaroxaban over dabigatran in terms of risk reduction of the primary endpoint. No subgroup favored warfarin and most dabigatran vs warfarin users favored neither drug. The variables that most influenced favoring one subgroup over another included Age, history of ischemic stroke, thromboembolism, estimated glomerular filtration rate, Race, and myocardial infarction. CONCLUSIONS: Among patients with AF treated with a NOAC or warfarin, a causal ML method identified patient subgroups with differences in outcomes associated with OAC use. The findings suggest that the effects of OACs are heterogeneous across subgroups of AF patients, which could help personalize the choice of OAC. Future prospective studies are needed to better understand the clinical impact of the subgroups with respect to OAC selection.

Virological characteristics and the rapid antigen test as deisolation criteria in immunocompromised patients with COVID-19: A prospective cohort study.

There are limited data supporting current Centers for Disease Control and Prevention guidelines for the isolation period in moderate to severely immunocompromised patients with coronavirus disease 2019 (COVID-19). Adult COVID-19 patients who underwent solid organ transplantation (SOT) or received active chemotherapy against hematologic malignancy were enrolled and weekly respiratory samples were collected. Samples with positive genomic real-time polymerase chain reaction results underwent virus culture and rapid antigen testing (RAT). A total of 65 patients (40 with hematologic malignancy and 25 SOT) were enrolled. The median duration of viable virus shedding was 4 weeks (interquartile range: 3-7). Multivariable analysis revealed that B-cell depletion (hazard ratio [HR]: 4.76) was associated with prolonged viral shedding, and COVID-19 vaccination (≥3 doses) was negatively associated with prolonged viral shedding (HR: 0.22). The sensitivity, specificity, positive predictive value, and negative predictive value of RAT for viable virus shedding were 79%, 76%, 74%, and 81%, respectively. The negative predictive value of RAT was only 48% (95% confidence interval [CI]: 33-65) in the samples from those with symptom onset ≤20 days, but it was as high as 92% (95% CI: 85-96) in the samples from those with symptom onset >20 days. About half of immunocompromised COVID-19 patients shed viable virus for ≥4 weeks from the diagnosis, and virus shedding was prolonged especially in unvaccinated patients with B-cell-depleting therapy treatment. RAT beyond 20 days in immunocompromised patients had a relatively high negative predictive value for viable virus shedding.

Short-Term Effectiveness of Oral Nirmatrelvir/Ritonavir Against the SARS-CoV-2 Omicron Variant and Culture-Positive Viral Shedding.

BACKGROUND: Information on the effectiveness of nirmatrelvir/ritonavir against the omicron is limited. The clinical response and viral kinetics to therapy in the real world need to be evaluated. METHODS: Mild to moderate coronavirus disease 2019 (COVID-19) patients with risk factors for severe illness were prospectively enrolled as a treatment group with nirmatrelvir/ritonavir therapy versus a control group with supportive care. Serial viral load and culture from the upper respiratory tract were evaluated for seven days, and clinical responses and adverse reactions were evaluated for 28 days. RESULTS: A total of 51 patients were analyzed including 40 in the treatment group and 11 in the control group. Faster symptom resolution during hospitalization (P = 0.048) was observed in the treatment group. Only minor adverse reactions were reported in 27.5% of patients. The viral load on Day 7 was lower in the treatment group (P = 0.002). The viral culture showed a positivity of 67.6% (25/37) vs. 100% (6/6) on Day 1, 0% (0/37) vs. 16.7 (1/6) on Day 5, and 0% (0/16) vs. 50.0% (2/4) on Day 7 in the treatment and control groups, respectively. CONCLUSIONS: Nirmatrelvir/ritonavir against the omicron was safe and resulted in negative viral culture conversion after Day 5 of treatment with better symptomatic resolution.

Non-Arteritic Ischemic Optic Neuropathy Following COVID-19 Vaccination in Korea: A Case Series.

BACKGROUND: To report the clinical manifestations of non-arteritic anterior ischemic optic neuropathy (NAION) cases after coronavirus disease 2019 (COVID-19) vaccination in Korea. METHODS: This multicenter retrospective study included patients diagnosed with NAION within 42 days of COVID-19 vaccination. We collected data on vaccinations, demographic features, presence of vascular risk factors, ocular findings, and visual outcomes of patients with NAION. RESULTS: The study included 16 eyes of 14 patients (6 men, 8 women) with a mean age of 63.5 ± 9.1 (range, 43-77) years. The most common underlying disease was hypertension, accounting for 28.6% of patients with NAION. Seven patients (50.0%) had no vascular risk factors for NAION. The mean time from vaccination to onset was 13.8 ± 14.2 (range, 1-41) days. All 16 eyes had disc swelling at initial presentation, and 3 of them (18.8%) had peripapillary intraretinal and/or subretinal fluid with severe disc swelling. Peripapillary hemorrhage was found in 50% of the patients, and one (6.3%) patient had peripapillary cotton-wool spots. In eight fellow eyes for which we were able to review the fundus photographs, the horizontal cup/disc ratio was less than 0.25 in four eyes (50.0%). The mean visual acuity was logMAR 0.6 ± 0.7 at the initial presentation and logMAR 0.7 ± 0.8 at the final visit. CONCLUSION: Only 64% of patients with NAION after COVID-19 vaccination have known vascular and ocular risk factors relevant to ischemic optic neuropathy. This suggests that COVID-19 vaccination may increase the risk of NAION. However, overall clinical features and visual outcomes of the NAION patients after COVID-19 vaccination were similar to those of typical NAION.

Protective Role of Ethanol Extract of Cibotium barometz (Cibotium Rhizome) against Dexamethasone-Induced Muscle Atrophy in C2C12 Myotubes.

Sarcopenia is a progressive muscle disease characterized by the loss of skeletal muscle mass, strength, function, and physical performance. Since the disease code was assigned, attention has been focused on natural products that can protect against muscle atrophy. Cibotium barometz (Cibotium Rhizome) has been used as an herbal medicine for the treatment of bone or joint diseases in Asian countries. However, no studies have identified the mechanism of action of Cibotium Rhizome on muscle atrophy related to sarcopenia at the site of myotubes. The aim of this study was to investigate the improvement effect of the ethanol extract of Cibotium Rhizome (ECR) on dexamethasone-induced muscle atrophy in an in vitro cell model, i.e., the C2C12 myotubes. High-performance liquid chromatography was performed to examine the phytochemicals in ECR. Seven peaks in the ECR were identified, corresponding to the following compounds: protocatechuic acid, (+)-catechin hydrate, p-coumaric acid, ellagic acid, chlorogenic acid, caffeic acid, and ferulic acid. In atrophy-like conditions induced by 100 µM dexamethasone for 24 h in C2C12, ECR increased the expression of the myosin heavy chain, p-Akt, the p-mammalian target of rapamycin (mTOR), p-p70S6K, and repressed the expression of regulated in development and DNA damage responses 1 (REDD1), kruppel-like factor 15 (KLF 15), muscle atrophy F-box, and muscle-specific RING finger protein-1 in C2C12. In addition, ECR alleviated dexamethasone-induced muscle atrophy by repressing REDD1 and KLF15 transcription in C2C12 myotubes, indicating the need for further studies to provide a scientific basis for the development of useful therapeutic agents using ECR to alleviate the effects of skeletal muscle atrophy or sarcopenia.

Vertical and horizontal ridge augmentation using customized three-dimensionally printed polycaprolactone mesh in atrophic posterior maxillae: a case report.

Polycaprolactone has exhibited expediency as a biomaterial for bone regenerative procedures preclinically. The present report of the two clinical cases in the posterior maxilla is the first to describe clinical application of a customized 3D printed polycaprolactone mesh for alveolar ridge augmentation. Two patients needing extensive ridge augmentation procedures for dental implant therapy were selected. Polycaprolactone meshes were virtually designed, 3D printed and applied in combination with a xenogeneic bone substitute. Cone-beam computed tomography was taken pre-operatively, immediately after the surgery, and 1.5 to 2 years after the delivery of implant prostheses. The serial cone-beam computed tomography images were superimposed to measure the augmented height and width at 1 mm increments from the implant platform to 3 mm apically. After 2 years, the mean [maximum, minimum] bone gain was 6.05 [8.64, 2.85] mm vertically and 7.77 [10.03, 6.18] mm horizontally at 1 mm below the implant platform. From immediately postoperative to 2 years, there was 14 % reduction of augmented ridged height and 24 % reduction of augmented width at 1 mm below the platform. All implants placed in augmented sites were successfully maintained until 2 years. The customized Polycaprolactone mesh might be a viable material for ridge augmentation in the atrophic posterior maxilla. This needs to be confirmed through randomized controlled clinical trials in future studies.

Duration of Humoral Immunity and Cross-Neutralizing Activity Against the Alpha, Beta, and Delta Variants After Wild-Type Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Prospective Cohort Study.

A prospective cohort study was conducted for adults with a diagnosis of with coronavirus disease 2019 (COVID-19). Convalescent blood samples were obtained 4, 6, and 11 months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The seropositivity of anti-spike antibody was maintained in all patients (100%) until 11 months after COVID-19 diagnosis. Neutralizing antibody levels against wild-type SARS-CoV-2 gradually decreased but remained positive in >50% of patients 11 months after diagnosis: in 98.5% (67 of 68) at 4 months, 86.8% (46 of 53) at 6 months, and 58.8% (40 of 68) at 11 months. However, cross-neutralizing activity against the Beta and Delta variants was attenuated 2.53-fold and 2.93-fold, respectively, compared with the wild-type strain.

Longitudinal Analysis of Memory T-Cell Responses in Survivors of Middle East Respiratory Syndrome.

BACKGROUND: Middle East respiratory syndrome (MERS) is a highly lethal respiratory disease caused by a zoonotic betacoronavirus. The development of effective vaccines and control measures requires a thorough understanding of the immune response to this viral infection. METHODS: We investigated cellular immune responses up to 5 years after infection in a cohort of 59 MERS survivors by performing enzyme-linked immunospot assay and intracellular cytokine staining after stimulation of peripheral blood mononuclear cells with synthetic viral peptides. RESULTS: Memory T-cell responses were detected in 82%, 75%, 69%, 64%, and 64% of MERS survivors from 1-5 years post-infection, respectively. Although the frequency of virus-specific interferon gamma (IFN-γ)-secreting T cells tended to be higher in moderately/severely ill patients than in mildly ill patients during the early period of follow-up, there was no significant difference among the different clinical severity groups across all time points. While both CD4+ and CD8+ T cells were involved in memory T-cell responses, CD4+ T cells persisted slightly longer than CD8+ T cells. Both memory CD4+ and CD8+ T cells recognized the E/M/N proteins better than the S protein and maintained their polyfunctionality throughout the period examined. Memory T-cell responses correlated positively with antibody responses during the initial 3-4 years but not with maximum viral loads at any time point. CONCLUSIONS: These findings advance our understanding of the dynamics of virus-specific memory T-cell immunity after MERS-coronavirus infection, which is relevant to the development of effective T cell-based vaccines.

Microglial cell response in α7 nicotinic acetylcholine receptor-deficient mice after systemic infection with Escherichia coli.

BACKGROUND: Development of neurodegeneration in older people has been associated with microglial cell activation triggered by systemic infection. We hypothesize that α7 nicotinic acetylcholine receptor (α7nAChR) plays an important role in regulation of this process. METHODS: 8- to 10-week-old male wild-type (WT) and α7nAChR knock-out (α7nAChR-/-) mice were intraperitoneally inoculated with live Escherichia (E.) coli or saline. After inoculation, all mice were treated with ceftriaxone (an antimicrobial drug) at 12 and 24 h and killed at 2 or 3 days. The microglial response was characterized by immunohistochemical staining with an ionized calcium-binding adaptor molecule 1 (Iba-1) antibody and flow cytometry. To quantify inflammatory response, mRNA expression of pro- and anti-inflammatory mediators was measured in brain and spleen. RESULTS: We observed no differences in Iba-1 positive cell number or morphology and flow cytometry (CD11b, CD45 and CD14) of microglial cells between WT and α7nAChR-/- mice after systemic infection. Infected α7nAChR-/- mice showed significantly higher mRNA expression in brain for tumor necrosis factor alpha (TNF-α) at day 2 and 3, interleukin 6 (IL-6) at day 2 and monocyte chemotactic protein 1 (MCP-1) and suppressor of cytokine signaling 1 (SOCS1) at day 3, there was significantly lower mRNA expression in brain for mitogen-activated protein kinase 1 (MAPK1) at day 2 and 3, high-mobility group 1 (HMGB-1) and CD11b at day 2, and deubiquitinase protein A20 (A20) at day 3 compared to infected WT mice. INTERPRETATION: Loss of function of α7nAChR during systemic infection led to an increased expression of TNF-α and IL-6 in brain after systemic infection with E. coli, but not to distinct differences in microglial cell number or morphological activation of microglia.

Possibility of Pseudo-Obstruction in Lacrimal Canalicular Obstruction Diagnosed with Dacryocystography.

INTRODUCTION: Endoscopic dacryocystorhinostomy (DCR) is the treatment of choice for patients with lacrimal drainage system obstruction. Dacryocystography (DCG) is one of the most common preoperative studies and considered as a useful test demonstrating the anatomy of lacrimal drainage systems. OBJECTIVE: This study was designed to evaluate the diagnostic efficacy of DCG for canalicular obstruction and to compare surgical outcomes between true-obstruction versus pseudo-obstruction diagnosed with DCG. METHODS: A retrospective study was performed on 45 consecutive patients with lacrimal canalicular obstruction who had underwent endoscopic DCR with silicone tube insertion from January 2009 to December 2014 at a single tertiary hospital. A review of medical records included demographic data, preoperative symptoms and signs, results of intraoperative canalicular probing, and surgical outcomes including the postoperative symptom improvement and endoscopic finding. RESULTS: Of 45 patients, 34 patients (75.6%) had true-canalicular obstructions and 11 patients (24.4%) had pseudo-canalicular obstructions. The success rate of endoscopic DCR was 50% (17 of 34) in cases with true-canalicular obstruction while 90.9% (10 of 11) in pseudo-canalicular obstruction (p value <0.05). No intraoperative or postoperative complications including sinusitis or synechia were found. CONCLUSIONS: About a quarter of lacrimal canalicular obstruction cases diagnosed with DCG seem to be pseudo-obstruction. The success rate of endoscopic DCR in pseudo-canalicular obstruction is similar to that of saccal and nasolacrimal ductal obstruction.

Factors Associated With Viral Load Kinetics of Middle East Respiratory Syndrome Coronavirus During the 2015 Outbreak in South Korea.

We conducted a retrospective study of Middle East respiratory syndrome coronavirus (MERS-CoV) viral load kinetics using data from patients hospitalized with MERS-CoV infection between 19 May and 20 August 2015. Viral load trajectories were considered over the hospitalization period using 1714 viral load results measured in serial respiratory specimens of 185 patients. The viral load levels were significantly higher among nonsurvivors than among survivors (P = .003). Healthcare workers (P = .001) and nonspreaders (P < .001) had significantly lower viral loads. Viral RNA was present on the day of symptom onset and peaked 4-10 days after symptom onset.

Longitudinal Assessment of Antisevere Acute Respiratory Syndrome Coronavirus 2 Immune Responses for Six Months Based on the Clinical Severity of Coronavirus Disease 2019.

BACKGROUND: There is insufficient data on the longevity of immunity acquired after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: We aimed to evaluate the duration of SARS-CoV-2-specific humoral and cellular immunity according to the clinical severity of coronavirus disease 2019 (COVID-19). The study population comprised asymptomatic (n = 14), symptomatic/nonpneumonic (n = 42), and pneumonic (n = 41) patients. RESULTS: The anti-SARS-CoV-2 immunoglobulin class G and neutralizing antibody (NAb) titers lasted until 6 months after diagnosis, with positivity rates of 66.7% and 86.9%, respectively. Older age, prolonged viral shedding, and accompanying pneumonia were more frequently found in patients with sustained humoral immunity. Severe acute respiratory syndrome coronavirus 2-specific T-cell response was strongly observed in pneumonic patients and prominent in individuals with sustained humoral immunity. CONCLUSIONS: In conclusion, most (>85%) patients carry NAb until 6 months after diagnosis of SARS-CoV-2 infection, providing insights for establishing vaccination strategies against COVID-19.

Sustained Responses of Neutralizing Antibodies Against Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in Recovered Patients and Their Therapeutic Applicability.

BACKGROUND: Zoonotic coronaviruses have emerged as a global threat by causing fatal respiratory infections. Given the lack of specific antiviral therapies, application of human convalescent plasma retaining neutralizing activity could be a viable therapeutic option that can bridges this gap. METHODS: We traced antibody responses and memory B cells in peripheral blood collected from 70 recovered Middle East respiratory syndrome coronavirus (MERS-CoV) patients for 3 years after the 2015 outbreak in South Korea. We also used a mouse infection model to examine whether the neutralizing activity of collected sera could provide therapeutic benefit in vivo upon lethal MERS-CoV challenge. RESULTS: Anti-spike-specific IgG responses, including neutralizing activity and antibody-secreting memory B cells, persisted for up to 3 years, especially in MERS patients who suffered from severe pneumonia. Mean antibody titers gradually decreased annually by less than 2-fold. Levels of antibody responses were significantly correlated with fever duration, viral shedding periods, and maximum viral loads observed during infection periods. In a transgenic mice model challenged with lethal doses of MERS-CoV, a significant reduction in viral loads and enhanced survival was observed when therapeutically treated with human plasma retaining a high neutralizing titer (> 1/5000). However, this failed to reduce pulmonary pathogenesis, as revealed by pathological changes in lungs and initial weight loss. CONCLUSIONS: High titers of neutralizing activity are required for suppressive effect on the viral replication but may not be sufficient to reduce inflammatory lesions upon fatal infection. Therefore, immune sera with high neutralizing activity must be carefully selected for plasma therapy of zoonotic coronavirus infection.