Is Omicron really mild? – Comparative analysis of comorbidities and disease outcomes associated with SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants

Purpose Multiple variants of SARS-CoV-2 from Alpha to Omicron have an estimated 6.1 million deaths globally till date. These variants have been found to vary in transmissibility and severity. The present study deals with comparison of morbidity and mortality with SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants. Materials and method An observational retrospective cohort study was conducted on a cohort of laboratory confirmed patients of SARS-CoV-2 diagnosed by qRT-PCR of nasopharyngeal swabs in periods;April-2021 and January-2022;that were sequenced and variants were recorded. Patients were invited for a telephonic interview after voluntary and informed consent was obtained from each participant wherein, the demographics, co-morbidities, oxygen requirement and mortality outcomes of the patients were enquired about. Results A total of 200 patients, with 100 from each period were included in the study. Major comorbidities in patients included hypertension, diabetes mellitus and pulmonary disease. Patients who succumbed to the Delta variant (26%) were higher as compared to the Omicron variant (10%);with the elderly (68 ​± ​9.7 ​years) having significant mortality during the Omicron variant. The mortality was increased in patients with comorbidities as with hypertension (53.8%, 70%), diabetes mellitus (26.9%, 40%), chronic pulmonary disease (30.8%, 20%), and smoking (15.4%, 40%) in the patients infected with both Delta and Omicron variants, respectively. Conclusion The study concluded that the newer strains of SARS-CoV-2 have potential of high transmissibility and milder disease for the population by large, however, for patients with comorbidities have a higher proportion of adverse outcomes, irrespective of the variant.

Optical Coherence Tomography Angiography Parameters of the Retina in SARS-CoV-2 Recovered Subjects.

INTRODUCTION: This study aims to evaluate retinochoroidal optical coherence tomography angiography (OCTA) parameters in patients recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: This study was an observational study that included 80 subjects being discharged after having negative reports on the reverse transcription-polymerase chain reaction (RT-PCR) test for SARS-CoV-2 to evaluate OCTA parameters of the retina. The subjects underwent an ophthalmic evaluation that included best-corrected visual acuity (BCVA), intraocular pressure (IOP), color vision (CV), contrast sensitivity (CS), and optical coherence tomography (OCT) parameters. OCTA was done for all patients and was evaluated for foveal avascular zone (FAZ) area, perimeter, and circularity index, and vessel density (VD) in superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), outer retina chorio-capillaries (ORCC), chorio-capillaries (CC), and choroid (C) using 3 x 3 mm scans. The OCTA parameters were compared with normative data of the Indian population for various parameters in question. RESULTS: The subjects included 54/80 (67.5%) males and 26/80 (32.5%) females having a mean age of 52.40 ± 15.71 (18-60) years. The systemic evaluation revealed 38.75% of subjects had hypertension, 30% had diabetes, 20% had kidney disease, 5% had tuberculosis, and 3.75% had coronary artery disease. The mean distance BCVA was logarithm of the minimum angle of resolution (LogMAR) (1.17 ± 0.22), mean IOP was 17.0 ± 4.0 mmHg, mean CS was 2.13 ± 0.36, 50.62% of subjects had normal CV on Farnsworth test while 47% had tritanopia, and none of the subjects had red-green CV defect on Ishihara plates. The OCT scan was normal in 90% of eyes while the posterior vitreous detachment was seen in 4% of eyes, broad vitreomacular adhesion in 2.5% of eyes, and the globally adherent epiretinal membrane was seen in 2.5% of eyes. The mean central macular thickness (CMT) measured 245.14 ± 28.41 micrometers. The mean FAZ area measured 0.37 ± 0.15 mm2, the perimeter was 3.28 ± 1.08 mm, and the circularity index measured 0.41 ± 0.10. The average VD in SCP measured 16.06 ± 12.29, in DCP measured 9.11 ± 8.75, in OR measured 6.38 ± 7.37, in ORCC measured 42.53 ± 12.46, in CC measured 25.83 ± 16.31, and in C measured 25.52 ± 17.49. The VD in coronavirus disease 2019 (COVID-19) subjects was significantly lesser than that in the healthy Indian population in all layers except ORCC. CONCLUSIONS: The SARS-CoV-2 recovered subjects have a reduced VD in retinochoroidal layers from COVID-19, an underlying systemic disease, or both. The CS values fall within normal limits. Several subjects show tritanopia on the Farnsworth test but no red-green CV defect on Ishihara plates.

Evaluation of Performance of Detection of Immunoglobulin G and Immunoglobulin M Antibody Against Spike Protein of SARS-CoV-2 by a Rapid Kit in a Real-Life Hospital Setting.

Background: Antibody testing is often used for serosurveillance of coronavirus disease 2019 (COVID-19). Enzyme-linked immunosorbent assay and chemiluminescence-based antibody tests are quite sensitive and specific for such serological testing. Rapid antibody tests against different antigens are developed and effectively used for this purpose. However, their diagnostic efficiency, especially in real-life hospital setting, needs to be evaluated. Thus, the present study was conducted in a dedicated COVID-19 hospital in New Delhi, India, to evaluate the diagnostic efficacy of a rapid antibody kit against the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Sixty COVID-19 confirmed cases by reverse transcriptase-polymerase chain reaction (RT-PCR) were recruited and categorized as early, intermediate, and late cases based on the days passed after their first RT-PCR-positive test report, with 20 subjects in each category. Twenty samples from pre-COVID era and 20 RT-PCR-negative collected during the study period were taken as controls. immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against the RBD of the spike (S) protein of SARS-CoV-2 virus were detected by rapid antibody test and compared with the total antibody against the nucleocapsid (N) antigen of SARS-CoV-2 by electrochemiluminescence-based immunoassay (ECLIA). Results: The detection of IgM against the RBD of the spike protein by rapid kit was less sensitive and less specific for the diagnosis of SARS-CoV-2 infection. However, diagnostic efficacy of IgG by rapid kit was highly sensitive and specific when compared with the total antibody against N antigen measured by ECLIA. Conclusion: It can be concluded that detection of IgM against the RBD of S protein by rapid kit is less effective, but IgG detection can be used as an effective diagnostic tool for SARS-CoV-2 infection in real-life hospital setting.

Evaluation of Performance of Detection of Immunoglobulin G and Immunoglobulin M Antibody Against Spike Protein of SARS-CoV-2 by a Rapid Kit in a Real-Life Hospital Setting

Background Antibody testing is often used for serosurveillance of coronavirus disease 2019 (COVID-19). Enzyme-linked immunosorbent assay and chemiluminescence-based antibody tests are quite sensitive and specific for such serological testing. Rapid antibody tests against different antigens are developed and effectively used for this purpose. However, their diagnostic efficiency, especially in real-life hospital setting, needs to be evaluated. Thus, the present study was conducted in a dedicated COVID-19 hospital in New Delhi, India, to evaluate the diagnostic efficacy of a rapid antibody kit against the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods Sixty COVID-19 confirmed cases by reverse transcriptase–polymerase chain reaction (RT-PCR) were recruited and categorized as early, intermediate, and late cases based on the days passed after their first RT-PCR–positive test report, with 20 subjects in each category. Twenty samples from pre-COVID era and 20 RT-PCR–negative collected during the study period were taken as controls. immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against the RBD of the spike (S) protein of SARS-CoV-2 virus were detected by rapid antibody test and compared with the total antibody against the nucleocapsid (N) antigen of SARS-CoV-2 by electrochemiluminescence-based immunoassay (ECLIA). Results The detection of IgM against the RBD of the spike protein by rapid kit was less sensitive and less specific for the diagnosis of SARS-CoV-2 infection. However, diagnostic efficacy of IgG by rapid kit was highly sensitive and specific when compared with the total antibody against N antigen measured by ECLIA. Conclusion It can be concluded that detection of IgM against the RBD of S protein by rapid kit is less effective, but IgG detection can be used as an effective diagnostic tool for SARS-CoV-2 infection in real-life hospital setting.

Sensitivity of liquid-based cytology in the diagnosis of mucormycosis in COVID-19 treated patients.

BACKGROUND: The coronavirus disease 2019 (COVID-19) infection caused by the novel severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) is associated with a wide range of disease patterns, ranging from mild to life-threatening pneumonia. COVID-19 can be associated with a suppressed immune response and/or hyperinflammatory state due to cytokine storm. Reduced immunity, combined with steroid usage to prevent cytokine storm along with various pre-existing co morbidities can prove to be a fertile ground for various secondary bacterial and fungal infection, including mucormycosis. Diagnosis of mucor is a challenging task given high negativity rate of various detection methods. While histopathology is considered the gold standard, the acquisition of necessary tissue biopsy specimens requires invasive procedures and is time consuming. METHOD: In this study various methods of mucor detection, like conventional cytopathology (CCP), liquid-based cytology (LBC, BD SurepathTM ), potassium hydroxide mount (KOH) preparation, culture and histopathology were analysed. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for various methods. RESULTS: This study showed that LBC has sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 72.4%,100%,100% and 38.4% respectively. CONCLUSION: This study showed that, liquid-based cytology (LBC) can be a rapid and effective alternative to histopathology in mucor diagnosis.

Basic virology of SARS-CoV 2

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly transmissible pathogenic coronavirus emerged in late 2019 causing a pandemic of acute respiratory disease, named ‘coronavirus disease 2019’ (COVID-19). It has spread fast all over the world posing an extraordinary threat to global public health. Along with SARS-CoV-2, there are seven human coronaviruses. Those causing mild diseases are the 229E, OC43, NL63 and HKU1, and the pathogenic ones are SARSCoV, MERS-CoV and SARS-CoV-2. Objective This review has highlighted the basic virology of SARS CoV-2 including its origin, structure, genomic characteristics, pathogenesis, immunological response and clinical manifestation along with the key difference of SARS CoV2 from the previous Coronaviruses. Content Coronaviruses are spherical and enveloped with club-shaped spikes on the surface. It has a large positive sense, single stranded RNA genome within the nucleocapsid with a helical symmetry. It has been known to cause infection to innumerable mammalian hosts, like humans, cats, bats, civets, dogs, and camels. The viral genome contains four major structural proteins: the spike (S), membrane (M), envelope (E) and the nucleocapsid (N) protein encoded within the 3’ end of the genome. Virus binds to the host cell by the S protein with specific receptor. Following receptor binding, the virus enters host cell cytosol and there is fusion of the viral and cellular membranes followed by the translation of the viral genomic RNA. Following the viral replication and sub-genomic RNA synthesis, there is formation of the mature virus. The virions are then transported to the cell surface in vesicles and are released by exocytosis.

Accelerating the discovery of antifungal peptides using deep temporal convolutional networks.

The application of machine intelligence in biological sciences has led to the development of several automated tools, thus enabling rapid drug discovery. Adding to this development is the ongoing COVID-19 pandemic, due to which researchers working in the field of artificial intelligence have acquired an active interest in finding machine learning-guided solutions for diseases like mucormycosis, which has emerged as an important post-COVID-19 fungal complication, especially in immunocompromised patients. On these lines, we have proposed a temporal convolutional network-based binary classification approach to discover new antifungal molecules in the proteome of plants and animals to accelerate the development of antifungal medications. Although these biomolecules, known as antifungal peptides (AFPs), are part of an organism's intrinsic host defense mechanism, their identification and discovery by traditional biochemical procedures is arduous. Also, the absence of a large dataset on AFPs is also a considerable impediment in building a robust automated classifier. To this end, we have employed the transfer learning technique to pre-train our model on antibacterial peptides. Subsequently, we have built a classifier that predicts AFPs with accuracy and precision of 94%. Our classifier outperforms several state-of-the-art models by a considerable margin. The results of its performance were proven as statistically significant using the Kruskal-Wallis H test, followed by a post hoc analysis performed using the Tukey honestly significant difference (HSD) test. Furthermore, we identified potent AFPs in representative animal (Histatin) and plant (Snakin) proteins using our model. We also built and deployed a web app that is freely available at https://tcn-afppred.anvil.app/ for the identification of AFPs in protein sequences.

Utility of Antigen-Based Rapid Diagnostic Test for Detection of SARS-CoV-2 Virus in Routine Hospital Settings.

OBJECTIVE: This study aims to evaluate the performance of an antigen-based rapid diagnostic test (RDT) for the detection of the SARS-CoV-2 virus. METHODS: A cross-sectional study was conducted on 677 patients. Two nasopharyngeal swabs and 1 oropharyngeal swab were collected from patients. The RDT was performed onsite by a commercially available immune-chromatographic assay on the nasopharyngeal swab. The nasopharyngeal and oropharyngeal swabs were examined for SARS-CoV-2 RNA by real-time reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay. RESULTS: The overall sensitivity of the SARS-CoV-2 RDT was 34.5% and the specificity was 99.8%. The positive predictive value and negative predictive value of the test were 96.6% and 91.5%, respectively. The detection rate of RDT in RT-qPCR positive results was high (45%) for cycle threshold values <25. CONCLUSION: The utility of RDT is in diagnosing symptomatic patients and may not be particularly suited as a screening tool for patients with low viral load. The low sensitivity of RDT does not qualify its use as a single test in patients who test negative; RT-qPCR continues to be the gold standard test.

Deep-AVPpred: Artificial Intelligence Driven Discovery of Peptide Drugs for Viral Infections.

Rapid increase in viral outbreaks has resulted in the spread of viral diseases in diverse species and across geographical boundaries. The zoonotic viral diseases have greatly affected the well-being of humans, and the COVID-19 pandemic is a burning example. The existing antivirals have low efficacy, severe side effects, high toxicity, and limited market availability. As a result, natural substances have been tested for antiviral activity. The host defense molecules like antiviral peptides (AVPs) are present in plants and animals and protect them from invading viruses. However, obtaining AVPs from natural sources for preparing synthetic peptide drugs is expensive and time-consuming. As a result, an in-silico model is required for identifying new AVPs. We proposed Deep-AVPpred, a deep learning classifier for discovering AVPs in protein sequences, which utilises the concept of transfer learning with a deep learning algorithm. The proposed classifier outperformed state-of-the-art classifiers and achieved approximately 94% and 93% precision on validation and test sets, respectively. The high precision indicates that Deep-AVPpred can be used to propose new AVPs for synthesis and experimentation. By utilising Deep-AVPpred, we identified novel AVPs in human interferons- α family proteins. These AVPs can be chemically synthesised and experimentally verified for their antiviral activity against different viruses. The Deep-AVPpred is deployed as a web server and is made freely available at https://deep-avppred.anvil.app, which can be utilised to predict novel AVPs for developing antiviral compounds for use in human and veterinary medicine.

Deep-AFPpred: identifying novel antifungal peptides using pretrained embeddings from seq2vec with 1DCNN-BiLSTM.

Fungal infections or mycosis cause a wide range of diseases in humans and animals. The incidences of community acquired; nosocomial fungal infections have increased dramatically after the emergence of COVID-19 pandemic. The increase in number of patients with immunodeficiency / immunosuppression related diseases, resistance to existing antifungal compounds and availability of limited therapeutic options has triggered the search for alternative antifungal molecules. In this direction, antifungal peptides (AFPs) have received a lot of interest as an alternative to currently available antifungal drugs. Although the AFPs are produced by diverse population of living organisms, identifying effective AFPs from natural sources is time-consuming and expensive. Therefore, there is a need to develop a robust in silico model capable of identifying novel AFPs in protein sequences. In this paper, we propose Deep-AFPpred, a deep learning classifier that can identify AFPs in protein sequences. We developed Deep-AFPpred using the concept of transfer learning with 1DCNN-BiLSTM deep learning algorithm. The findings reveal that Deep-AFPpred beats other state-of-the-art AFP classifiers by a wide margin and achieved approximately 96% and 94% precision on validation and test data, respectively. Based on the proposed approach, an online prediction server is created and made publicly available at https://afppred.anvil.app/. Using this server, one can identify novel AFPs in protein sequences and the results are provided as a report that includes predicted peptides, their physicochemical properties and motifs. By utilizing this model, we identified AFPs in different proteins, which can be chemically synthesized in lab and experimentally validated for their antifungal activity.

COVID associated mucormycosis: A preliminary study from a dedicated COVID Hospital in Delhi.

BACKGROUND: It is an incontrovertible fact that the Rhino Orbital Cerebral Mucormycosis (ROCM) upsurge is being seen in the context of COVID-19 in India. Briefly presented is evidence that in patients with uncontrolled diabetes, a dysfunctional immune system due to SARS-COV-2 and injudicious use of corticosteroids may be largely responsible for this malady. OBJECTIVE: To find the possible impact of COVID 19 infection and various co-morbidities on occurrence of ROCM and demonstrate the outcome based on medical and surgical interventions. METHODOLOGY: Prospective longitudinal study included patients diagnosed with acute invasive fungal rhinosinusitis after a recent COVID-19 infection. Diagnostic nasal endoscopy (DNE) was performed on each patient and swabs were taken and sent for fungal KOH staining and microscopy. Medical management included Injection Liposomal Amphotericin B, Posaconazole and Voriconazole. Surgical treatment was restricted to patients with RT PCR negative results for COVID-19. Endoscopic, open, and combined approaches were utilized to eradicate infection. Follow-up for survived patients was maintained regularly for the first postoperative month. RESULTS: Out of total 131 patients, 111 patients had prior history of SARS COVID 19 infection, confirmed with a positive RT-PCR report and the rest 20 patients had no such history. Steroids were received as a part of treatment in 67 patients infected with COVID 19. Among 131 patients, 124 recovered, 1 worsened and 6 died. Out of 101 known diabetics, 98 recovered and 3 had fatal outcomes. 7 patients with previous history of COVID infection did not have any evidence of Diabetes mellitus, steroid intake or any other comorbidity. CONCLUSION: It can be concluded that ROCM upsurge seen in the context of COVID-19 in India was mainly seen in patients with uncontrolled diabetes, a dysfunctional immune system due to SARS-COV-2 infection and injudicious use of corticosteroids.

Rhino-Orbito-Cerebral-Mucormycosis During the COVID-19 Second Wave in 2021 - A Preliminary Report from a Single Hospital.

PURPOSE: To list the clinico-epidemiological profile and possible risk factors of COVID-19 associated rhino-orbital-cerebral mucormycosis (CA-ROCM) patients presenting to a COVID dedicated hospital during the second wave of COVID-19 in India. PATIENTS AND METHODS: A cross-sectional, single-center study was done on 60 cases of probable CA-ROCM based on clinical features and supportive diagnostic nasal endoscopic findings and/or radiologic findings. Patients with recent or active COVID-19 were included. The demographic profile, clinical features, possible risk factors and diagnostic workup (microbiological, pathological and radiological) were analysed to identify the triggering factors for CA-ROCM. RESULTS: The age of patients ranged from 29 to 75 years and male-female ratio was 3:1. The duration between the first positive COVID report and onset of CA-ROCM was 0 to 47 days. Forty-nine (81.66%) patients had a recent COVID infection and 11 (18.33%) had active COVID infection at presentation. Thirty-five patients (58%) had ocular/orbital involvement at presentation. In the affected eye, 10 had no perception of light and in the rest visual acuity ranged from log MAR 0 to +1.5. Ocular manifestations were ptosis (29), ophthalmoplegia (23), periocular tenderness and edema (33), proptosis (14), black discoloration of eyelids (3), facial palsy (3), endophthalmitis (4), retinal artery occlusion (8), disc edema (4) and disc pallor (5). Twenty-two (25%) patients had neither received steroids nor oxygen. Thirty patients (50%) were managed with oxygen while 38 patients (63.3%) with systemic steroids. The most common risk factor was diabetes in 59 patients. The average glycosylated hemoglobin (HbA1c) was 10.31 ± 2.59%. Systemic Amphotericin B was started in all the patients. Radical surgical debridement was performed in 12 patients and the remaining were planned. CONCLUSION: SARS-CoV-2 variant with accompanying glycaemic dysregulation was found to be the triggering factor for the epidemic of CA-ROCM.

Evidence of the presence of SARS-CoV-2 virus in atmospheric air and surfaces of a dedicated COVID hospital.

The present study was conducted from July 1, 2020 to September 25, 2020 in a dedicated coronavirus disease 2019 (COVID-19) hospital in Delhi, India to provide evidence for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in atmospheric air and surfaces of the hospital wards. Swabs from hospital surfaces (patient's bed, ward floor, and nursing stations area) and suspended particulate matter in ambient air were collected by a portable air sampler from the medicine ward, intensive care unit, and emergency ward admitting COVID-19 patients. By performing reverse-transcriptase polymerase chain reaction (RT-PCR) for E-gene and RdRp gene, SARS-CoV-2 virus was detected from hospital surfaces and particulate matters from the ambient air of various wards collected at 1 and 3-m distance from active COVID-19 patients. The presence of the virus in the air beyond a 1-m distance from the patients and surfaces of the hospital indicates that the SARS-CoV-2 virus has the potential to be transmitted by airborne and surface routes from COVID-19 patients to health-care workers working in COVID-19 dedicated hospital. This warrants that precautions against airborne and surface transmission of COVID-19 in the community should be taken when markets, industries, educational institutions, and so on, reopen for normal activities.

The seroprevalence of severe acute respiratory syndrome coronavirus 2 in Delhi, India: a repeated population-based seroepidemiological study.

BACKGROUND: Three rounds of a repeated cross-sectional serosurvey to estimate the change in seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were conducted from August to October 2020 in the state of Delhi, India, in the general population ≥5 y of age. METHODS: The selection of participants was through a multistage sampling design from all 11 districts and 280 wards of the city-state, with multistage allocation proportional to population size. The blood samples were screened using immunoglobulin G (IgG) enzyme-linked immunosorbent assay kits. RESULTS: We observed a total of 4267 (N=150 46), 4311 (N=17 409) and 3829 (N=15 015) positive tests indicative of the presence of IgG antibody to SARS-CoV-2 during the August, September and October 2020 serosurvey rounds, respectively. The adjusted seroprevalence declined from 28.39% (95% confidence interval [CI] 27.65 to 29.14) in August to 24.08% (95% CI 23.43 to 24.74) in September and 24.71% (95% CI 24.01 to 25.42) in October. On adjusted analysis, participants with lower per capita income, living in slums or overcrowded households and those with diabetes comorbidity had significantly higher statistical odds of having antibody positivity (p<0.01). CONCLUSIONS: Nearly one in four residents in Delhi, India ≥5 y of age had the SARS-CoV-2 infection during August-October 2020.

Longitudinal Serology of SARS-CoV-2-Infected Individuals in India: A Prospective Cohort Study.

Clinical and epidemiological characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are now widely available, but there are few data regarding longitudinal serology in large cohorts, particularly those from low-income and middle-income countries. We established an ongoing prospective cohort of 3,840 SARS-CoV-2-positive individuals according to RT-PCR in the Delhi-National Capital Region of India to document clinical and immunological characteristics during illness and convalescence. The immunoglobulin G (IgG) responses to the receptor binding domain (RBD) and nucleocapsid were assessed at 0 to 7 days, 10 to 28 days, and 6 to 10 weeks after infection. The clinical predictors of seroconversion were identified by multivariable regression analysis. The seroconversion rates during the postinfection windows of 0 to 7 days, 10 to 28 days, and 6 to 10 weeks were 46%, 84.7%, and 85.3%, respectively (N = 743). The proportion with a serological response increased with the severity of coronavirus disease 2019 (COVID-19). All participants with severe disease, 89.6% with mild to moderate infection, and 77.3% of asymptomatic participants had IgG antibodies to the RBD antigen. The threshold values for the nasopharyngeal viral RNA RT-PCR of a subset of asymptomatic and symptomatic seroconverters were comparable (P = 0.48) to those of nonseroconverters (P = 0.16) (N = 169). This is the first report of longitudinal humoral immune responses to SARS-CoV-2 over a period of 10 weeks in South Asia. The low seropositivity of asymptomatic participants and differences between assays highlight the importance of contextualizing the understanding of population serosurveys.

Seroprevalence of antibodies to SARS-CoV-2 and predictors of seropositivity among employees of a teaching hospital in New Delhi, India.

OBJECTIVE: Healthcare workers (HCWs) are at a high risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to the increased likelihood of clinical exposure during patient management. The study objective was to determine the seroprevalence of antibodies to SARS-CoV-2 and its predictors among hospital employees. METHODS: The cross-sectional study was conducted at a teaching hospital from August 2020 to September 2020 among 1,401 employees, including 1,217 HCWs, in New Delhi, India. The serum samples were examined for immunoglobulin G (IgG) antibodies to SARS-CoV-2 using the COVID Kavach-Anti-SARS-CoV-2 IgG Antibody Detection enzyme-linked immunosorbent assay kit. Data were collected electronically using the EpiCollect mobile platform. A p < 0.05 was considered to indicate statistical significance. RESULTS: A total of 169 participants (12.1%) had detectable IgG antibodies to SARS-CoV-2. The highest seropositivity rate was observed in the administrative staff (20.1%), while it was lowest among medical doctors (5.5%, p < 0.001). Male sex and ever having lived in a containment zone were independently associated with past infection with SARS-CoV-2. CONCLUSION: The seroprevalence of SARS-CoV-2 infection in health workers may be lower than in the general population in New Delhi. However, nonpharmaceutical interventions were not associated with a reduction in the risk of acquisition of SARS-CoV-2.

Comparative Evaluation of Tears and Nasopharyngeal Swab for SARS-CoV-2 in COVID-19 Dedicated Intensive Care Unit Patients.

Purpose: To compare the cycle threshold (Ct) values of tears and nasopharyngeal (NP) swab in severe COVID-19 ICU patients with positive NP swabs.Procedure: A cross-sectional study for the detection of SARS-CoV-2 by real-time RT-PCR on simultaneously collected NP swabs and tears was performed. Detailed demographic profile, including comorbidities, ocular, and systemic features were analyzed.Results: In the 78 cases, the mean tear positivity was 26.92% (21/78), 2 tear samples being positive despite a negative NP swab. The mean Ct value of tears and NP were 28.17 ± 4.76 and 23.71 ± 6.19, respectively (p= .003). None of the cases had ocular findings or relationship between tear positivity and comorbidity.Conclusions: The viral load of tears is less than the NP secretions with the possibility of prolonged shedding in tears. Tears act as an additional source of contact transmission in ICU that can possibly be decreased by frequent hand hygiene by the patient.Abbreviations: SARS-CoV-2: Severe acute respiratory syndrome coronavirus; RT-PCR: Real-time Reverse transcriptase-polymerase chain reaction; COVID-19: Corona virus disease 2019; ICU: Intensive care unit; RdRp: RNA-dependent RNA polymerase; ORF 1b: Open reading frame 1b; AIIR: Airborne infection isolation room; HCW: Health care workers; VTM: viral transport media; NP: Nasopharyngeal swab; PPE: Personal protective equipment.