Hybrid immunity from SARS-CoV-2 delta variant surge induced low to undetectable levels of neutralizing antibodies against Omicron variant

The Omicron variant of SARS-CoV-2 is capable of infecting unvaccinated, vaccinated and previously-infected individuals due to its ability to evade neutralization by antibodies. With three sub-lineages of Omicron emerging in the last four months, there is inadequate information on the quantitative antibody response generated upon natural infection with Omicron variant and whether these antibodies offer cross-protection against other sub-lineages of Omicron variant. In this study, we characterized the growth kinetics of Kappa, Delta and Omicron variants of SARS-CoV-2 in Calu-3 cells. Relatively higher amounts infectious virus titers, cytopathic effect and disruption of epithelial barrier functions was observed with Delta variant whereas infection with Omicron variant led to a more robust induction of interferon pathway, lower level of virus replication and mild effect on epithelial barrier. The replication kinetics of BA.1 and BA.2 sub-lineages of the Omicron variant were comparable in cell culture and natural Omicron infection in a subset of individuals led to a significant increase in binding and neutralizing antibodies to both BA.1 and BA.2 sub-lineages but these levels were lower than that produced against the Delta variant. Finally, we show that Cu2+, Zn2+ and Fe2+ salts inhibited in vitro RdRp activity but only Cu2+ and Fe2+ inhibited both the Delta and Omicron variants in cell culture. Thus, our results suggest that high levels of interferons induced upon infection with Omicron variant may counter virus replication and spread. Waning neutralizing antibody titers rendered subjects susceptible to infection by Omicron variant and natural Omicron infection elicits neutralizing antibodies that can cross-react with other sub-lineages of Omicron and other variants of concern.

Relative Importance of Various Inflammatory Markers and Their Critical Thresholds for COVID-19 Mortality

BackgroundVarious inflammatory markers are commonly assessed in many patients to help in the management of COVID-19 patients. It is not clear, though, how much risk of mortality their different levels of elevations entail, and which marker signifies more risk than others and how much. This study was undertaken to describe their levels and to answer these questions regarding eight inflammatory markers, namely, CRP, D-dimer, ferritin, IL-6, LDH, CPK, troponin-I. MethodsThe data were retrieved from the electronic records of 19852 CoViD-19 patients admitted to a chain of hospitals in north India from March 2020 to July 2021. Levels for most markers were available for more than 10,000 patients. In view of widely different ranges of values of different markers, we divided their values into quintiles (Qs) and studied the pattern of mortality and for running the logistic regression. In addition, logarithm transformation was also tried. The statistical distribution of the values was compared by Mann-Whitney test. Relative importance was judged by the mortality rates, area under the ROC curves (AUROCs), and the odds ratios. ResultsAlthough the mortality increased with decreasing ALC and increasing level of all the other markers, more than 70% survived even with levels in the extreme quintile. The adjusted odds ratio was the highest (7.62) for the Q5 levels of IL-6, closely followed by D-dimer (OR = 6.04). The AUROC was the highest (0.817) for LDH and the least (0.612) for CPK. However, the optimal cut-off for any marker could correctly classify not more than 80% deaths and the multivariable logistic regression could correctly classify patients with mortality in less than 24% cases. ConclusionAlthough elevated levels of all the markers and low values of ALC were significant risk factor but no firm evidence was available for any of the eight markers to be a major indicator of the mortality in COVID-19 unless they reach to a critical threshold. Among those studied, D-Dimer (>192 ng/mL) followed by IL-6 (>4.5 pg/mL) had stronger association with mortality even with moderate and higher end of the normal levels and LDH (>433 U/L) and troponin-I (>0.002ng/mL) with only steeply increased levels. Ferritin had modest association, and CPK, CRP and ALC were a relatively poor risk of mortality.

Clinicogenomic analysis of breakthrough infections by SARS CoV2 variants after ChAdOx1 nCoV- 19 vaccination in healthcare workers

BackgroundIndia saw a massive surge and emergence of SARS CoV2 variants. We elucidated clinical and humoral immune response and genomic analysis of vaccine breakthrough (VBT) infections after ChAdOx1 nCoV-19 vaccine in healthcare workers (HCWs). MethodsThe study was conducted on 1858 HCWs receiving two doses of ChAdOx1 nCoV-19 vaccine. Serial blood samples were collected to measure SARS CoV2 IgG and neutralizing antibodies. 46 RT-PCR positive samples from VBT infections were subjected to whole genome sequencing (WGS). ResultsInfection was confirmed in 219 (11.79%) HCWs of which 21.46% (47/219) were non-vaccinated, significantly more (p <0.001) than 9.52% (156/1639) vaccinated group. VBT infections were significantly higher in doctors and nurses compared to other hospital staff (p <0.001). Unvaccinated individuals had 1.57 times higher risk of infection compared to partially vaccinated (p 0.02) and 2.49 times than fully vaccinated (<0.001). Partially vaccinated were at higher risk of infection than fully vaccinated (RR 1.58,p 0.01). There were 3 (1.36%) severe cases and 1 death in unvaccinated group compared to none in the vaccinated. Non-response after 14 days of second dose was seen in 6.5% (3/46) and low antibody levels (1-4.62 S/CO) in 8.69% (4/46). Delta variant (B.1.617.2) was dominant (69.5%) and reinfection was documented in 4 (0.06%) HCWs. ConclusionsNearly one in ten vaccinated HCWs can get infected, more so with only single dose (13.65%) than two doses (8.62%). Fully vaccinated are better protected with higher humoral immune response. Genomic analysis revealed an alarming rise of Delta variant (B.1.617.2) in VBT infections.

Plasma gradient of soluble urokinase-type plasminogen activator receptor is linked to pathogenic plasma proteome and immune transcriptome and stratifies outcomes in severe COVID-19

Disease caused by SARS-CoV-2 coronavirus (COVID-19) has resulted in significant morbidity and mortality world-wide. A systemic hyper-inflammation characterizes the severe COVID-19 disease often associated with acute respiratory distress syndrome (ARDS). Blood biomarkers capable of risk stratification are of great importance in effective triage and critical care of severe COVID-19 patients. In the present study we report higher plasma abundance of soluble urokinase-type plasminogen activator receptor (sUPAR), expressed by an abnormally expanded circulating myeloid cell population, in severe COVID-19 patients with ARDS. Plasma sUPAR level was found to be linked to a characteristic proteomic signature of plasma, linked to coagulation disorders and complement activation. Receiver operator characteristics curve analysis identified a cut-off value of sUPAR at 1996.809 pg/ml that could predict survival in our cohort (Odds ratio: 2.9286, 95% confidence interval 1.0427-8.2257). Lower sUPAR level than this threshold concentration was associated with a differential expression of the immune transcriptome as well as favourable clinical outcomes, both in terms of survival benefit (Hazard ratio: 0.3615, 95% confidence interval 0.1433-0.912) and faster disease remission in our patient cohort. Thus we identified sUPAR as a key pathogenic circulating molecule linking systemic hyperinflammation to the hypercoagulable state and stratifying clinical outcomes in severe COVID-19 patients with ARDS.

Genomic characterization and Epidemiology of an emerging SARS-CoV-2 variant in Delhi, India

Delhi, the national capital of India, has experienced multiple SARS-CoV-2 outbreaks in 2020 and reached a population seropositivity of over 50% by 2021. During April 2021, the city became overwhelmed by COVID-19 cases and fatalities, as a new variant B.1.617.2 (Delta) replaced B.1.1.7 (Alpha). A Bayesian model explains the growth advantage of Delta through a combination of increased transmissibility and partial reduction of immunity elicited by prior infection (median estimates; x1.5-fold, 20% reduction). Seropositivity of an employee and family cohort increased from 42% to 86% between March and July 2021, with 27% reinfections, as judged by increased antibody concentration after previous decline. The likely high transmissibility and partial evasion of immunity by the Delta variant contributed to an overwhelming surge in Delhi. One-Sentence SummaryDelhi experienced an overwhelming surge of COVID-19 cases and fatalities peaking in May 2021 as the highly transmissible and immune evasive Delta variant replaced the Alpha variant.

SARS-CoV-2 B.1.617 emergence and sensitivity to vaccine-elicited antibodies

The SARS-CoV-2 B.1.617.2 (Delta) variant was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha). In vitro, B.1.617.2 is 6-fold less sensitive to serum neutralising antibodies from recovered individuals, and 8-fold less sensitive to vaccine-elicited antibodies as compared to wild type Wuhan-1 bearing D614G. Serum neutralising titres against B.1.617.2 were lower in ChAdOx-1 versus BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies against the receptor binding domain (RBD) and N-terminal domain (NTD), in particular to the clinically approved bamlavinimab and imdevimab monoclonal antibodies. B.1.617.2 demonstrated higher replication efficiency in both airway organoid and human airway epithelial systems as compared to B.1.1.7, associated with B.1.617.2 spike being in a predominantly cleaved state compared to B.1.1.7. Additionally we observed that B.1.617.2 had higher replication and spike mediated entry as compared to B.1.617.1, potentially explaining B.1.617.2 dominance. In an analysis of over 130 SARS-CoV-2 infected healthcare workers across three centres in India during a period of mixed lineage circulation, we observed substantially reduced ChAdOx-1 vaccine efficacy against B.1.617.2 relative to non-B.1.617.2. Compromised vaccine efficacy against the highly fit and immune evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era.

Severe Acute Respiratory Syndrome Coronavirus-2 genome sequence variations relate to morbidity and mortality in Coronavirus Disease-19

Outcome of infection with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) may depend on the host, virus or the host-virus interaction-related factors. Complete SARS-CoV-2 genome was sequenced using Illumina and Nanopore platforms from naso-/oro-pharyngeal ribonucleic acid (RNA) specimens from COVID-19 patients of varying severity and outcomes, including patients with mild upper respiratory symptoms (n=35), severe disease ad-mitted to intensive care with respiratory and gastrointestinal symptoms (n=21), fatal COVID-19 outcome (n=17) and asymptomatic (n=42). Of a number of genome variants observed, p.16L>L (Nsp1), p.39C>C (Nsp3), p.57Q>H (ORF3a), p.71Y>Y (Membrane glycoprotein), p.194S>L (Nucleocapsid protein) were observed in similar frequencies in different patient subgroups. However, seventeen other variants were observed only in symptomatic patients with severe and fatal COVID-19. Out of the latter, one was in the 5UTR (g.241C>T), eight were synonymous (p.14V>V and p.92L>L in Nsp1 protein, p.226D>D, p.253V>V, and p.305N>N in Nsp3, p.34G>G and p.79C>C in Nsp10 protein, p.789Y>Y in Spike protein), and eight were non-synonymous (p.106P>S, p.157V>F and p.159A>V in Nsp2, p.1197S>R and p.1198T>K in Nsp3, p.97A>V in RdRp, p.614D>G in Spike protein, p.13P>L in nucleocapsid). These were completely absent in the asymptomatic group. SARS-CoV-2 genome variations have a significant impact on COVID-19 presentation, severity and outcome.

RAY: CRISPR diagnostic for rapid and accurate detection of SARS-CoV2 variants on a paper strip

The COVID-19 pandemic originating in the Wuhan province of China in late 2019 has impacted global health, causing increased mortality among elderly patients and individuals with comorbid conditions. During the passage of the virus through affected populations, it has undergone mutations- some of which have recently been linked with increased viral load and prognostic complexities. Interestingly, several of these variants are point mutations that are difficult to diagnose using the gold standard quantitative real-time PCR (qPCR) method. This necessitates widespread sequencing which is expensive, has long turn-around times, and requires high viral load for calling mutations accurately. In this study, we show that the high specificity of Francisella novicida Cas9 (FnCas9) to point mismatches can be successfully adapted for the simultaneous detection of SARS-CoV2 infection as well as for detecting point mutations in the sequence of the virus obtained from patient samples. We report the detection of the mutation N501Y (earlier shown to be present in the British N501Y.V1, South African N501Y.V2, and Brazilian N501Y.V3 variants of SARS-CoV2) within an hour using paper strip chemistry. The results were corroborated using deep sequencing. Our design principle can be rapidly adapted for other mutations, highlighting the advantages of quick optimization and roll-out of CRISPR diagnostics (CRISPRDx) for disease surveillance even beyond COVID-19.

A highly thermotolerant, trimeric SARS-CoV-2 receptor binding domain derivative elicits high titers of neutralizing antibodies

The Receptor Binding Domain (RBD) of SARS-CoV-2 is the primary target of neutralizing antibodies. We designed a trimeric, highly thermotolerant glycan engineered RBD by fusion to a heterologous, poorly immunogenic disulfide linked trimerization domain derived from cartilage matrix protein. The protein expressed at a yield of [~]80-100 mg/liter in transiently transfected Expi293 cells, as well as CHO and HEK293 stable cell lines and formed homogeneous disulfide-linked trimers. When lyophilized, these possessed remarkable functional stability to transient thermal stress of upto 100 {degrees}C and were stable to long term storage of over 4 weeks at 37 {degrees}C unlike an alternative RBD-trimer with a different trimerization domain. Two intramuscular immunizations with a human-compatible SWE adjuvanted formulation, elicited antibodies with pseudoviral neutralizing titers in guinea pigs and mice that were 25-250 fold higher than corresponding values in human convalescent sera. Against the beta (B.1.351) variant of concern (VOC), pseudoviral neutralization titers for RBD trimer were [~] three-fold lower than against wildtype B.1 virus. RBD was also displayed on a designed ferritin-like Msdps2 nanoparticle. This showed decreased yield and immunogenicity relative to trimeric RBD. Replicative virus neutralization assays using mouse sera demonstrated that antibodies induced by the trimers neutralized all four VOC to date, namely B.1.1.7, B.1.351, P.1 and B.1.617.2 without significant differences. Trimeric RBD immunized hamsters were protected from viral challenge. The excellent immunogenicity, thermotolerance, and high yield of these immunogens suggest that they are a promising modality to combat COVID-19, including all SARS-CoV-2 VOC to date.

COVID-19 Risk Stratification and Mortality Prediction in Hospitalized Indian Patients

The clinical course of coronavirus disease 2019 (COVID-19) infection is highly variable with the vast majority recovering uneventfully but a small fraction progressing to severe disease and death. Appropriate and timely supportive care can reduce mortality and it is critical to evolve better patient risk stratification based on simple clinical data, so as to perform effective triage during strains on the healthcare infrastructure. This study presents risk stratification and mortality prediction models based on usual clinical data from 544 COVID-19 patients from New Delhi, India using machine learning methods. An XGboost classifier yielded the best performance on risk stratification (F1 score of 0.81). A logistic regression model yielded the best performance on mortality prediction (F1 score of 0.71). Significant biomarkers for predicting risk and mortality were identified. Examination of the data in comparison to a similar dataset with a Wuhan cohort of 375 patients was undertaken to understand the much lower mortality rates in India and the possible reasons thereof. The comparison indicated higher survival rate in the Delhi cohort even when patients had similar parameters as the Wuhan patients who died. Steroid administration was very frequent in Delhi patients, especially in surviving patients whose biomarkers indicated severe disease. This study helps in identifying the high-risk patient population and suggests treatment protocols that may be useful in countries with high mortality rates.

Clinical and immunological benefits of convalescent plasma therapy in severe COVID-19: insights from a single center open label randomised control trial

IntroductionA single center open label phase II randomised control trial was done to assess the pathogen and host-intrinsic factors influencing clinical and immunological benefits of passive immunization using convalescent plasma therapy (CPT), in addition to standard of care (SOC) therapy in severe COVID-19 patients, as compared to patients only on SOC therapy. MethodsConvalescent plasma was collected from patients recovered from COVID-19 following a screening protocol which also included measuring plasma anti SARS-CoV2 spike IgG content. Retrospectively, neutralizing antibody content was measured and proteome was characterized by LC-MS/MS for all convalescent plasma units that were transfused to patients. Severe COVID-19 patients with evidence for acute respiratory distress syndrome (ARDS) with PaO2/FiO2 ratio 100-300 (moderate ARDS) were recruited and randomised into two parallel arms of SOC and CPT, N=40 in each arm. Peripheral blood samples were collected on the day of enrolment (T1) followed by day3/4 (T2) and day 7 (T3). RT-PCR and sequencing was done for SARS-CoV2 RNA isolated from nasopharyngeal swabs collected at T1. A panel of cytokines and neutralizing antibody content were measured in plasma at all three timepoints. Patients were followed up for 30 days post-admission to assess the primary outcomes of all cause mortality and immunological correlates for clinical benefits. ResultsWhile across all age-groups no statistically significant clinical benefit was registered for patients in the CPT arm, significant immediate mitigation of hypoxia, reduction in hospital stay as well as survival benefit was recorded in severe COVID-19 patients with ARDS aged less than 67 years receiving convalescent plasma therapy. In addition to its neutralizing antibody content a prominent effect of convalescent plasma on attenuation of systemic cytokine levels possibly contributed to its benefits. ConclusionPrecise targeting of severe COVID-19 patients is necessary for reaping the clinical benefits of convalescent plasma therapy. Clinical trial registrationClinical Trial Registry of India No. CTRI/2020/05/025209

Clinical Profile of First 1000 COVID-19 Cases Admitted at Tertiary Care Hospitals and the Correlates of their Mortality: An Indian Experience

ObjectiveTo describe the clinical profile and factors leading to increased mortality in coronavirus disease (COVID-19) patients admitted to a group of hospitals in India. DesignA records-based study of the first 1000 patients with a positive result on real-time reverse transcriptase-polymerase-chain-reaction assay for SARS-CoV-2 admitted to our facilities. Various factors such as demographics, presenting symptoms, co-morbidities, ICU admission, oxygen requirement and ventilator therapy were studied. ResultsOf the 1000 patients, 24 patients were excluded due to lack of sufficient data. Of the remaining 976 in the early phase of the epidemic, males were admitted twice as much as females (67.1% and 32.9%, respectively). Mortality in this initial phase was 10.6% and slightly higher for males and steeply higher for older patients. More than 8% reported no symptoms and the most common presenting symptoms were fever (78.3%), productive cough (37.2%), and dyspnea (30.64%). More than one-half (53.6%) had no co-morbidity. The major co-morbidities were hypertension (23.7%), diabetes without (15.4%), and with complications (9.6%). The co-morbidities were associated with higher ICU admissions, greater use of ventilators as well as higher mortality. A total of 29.9% were admitted to the ICU, with a mortality rate of 32.2%. Mortality was steeply higher in those requiring ventilator support (55.4%) versus those who never required ventilation (1.4%). The total duration of hospital stay was just a day longer in patients admitted to the ICU than those who remained in wards. ConclusionMale patients above the age of 60 and with co-morbidities faced the highest rates of mortality. They should be admitted to the hospital in early stage of the disease and given aggressive treatment to help reduce the morbidity and mortality associated with COVID-19.

Kinetics of viral load, immunological mediators and characterization 1 of a SARS-CoV-2 isolate in mild COVID-19 patients during acute phase of infection

Over 95% of the COVID-19 cases are mild-to-asymptomatic who contribute to disease transmission whereas most of the severe manifestations of the disease are observed in elderly and in patients with comorbidities and dysregulation of immune response has been implicated in severe clinical outcomes. However, it is unclear whether asymptomatic or mild infections are due to low viral load or lack of inflammation. We have measured the kinetics of SARS-CoV-2 viral load in the respiratory samples and serum markers of inflammation in hospitalized COVID-19 patients with mild symptoms. We observed a bi-phasic pattern of virus load which was eventually cleared in most patients at the time of discharge. Viral load in saliva samples from a subset of patients showed good correlation with nasopharyngeal samples. Serum interferon levels were downregulated during early stages of infection but peaked at later stages correlating with elevated levels of T-cell cytokines and other inflammatory mediators such as IL-6 and TNF- which showed a bi-phasic pattern. The clinical recovery of patients correlated with decrease in viral load and increase in interferons and other cytokines which indicates an effective innate and adaptive immune function in mild infections. We further characterized one of the SARS-CoV-2 isolate by plaque purification and show that infection of lung epithelial cells (Calu-3) with this isolate led to cytopathic effect disrupting epithelial barrier function and tight junctions. Finally we showed that zinc was capable of inhibiting SARS-CoV-2 infection in this model suggesting a beneficial effect of zinc supplementation in COVID-19 infection. IMPORTANCEA majority of COVID-19 patients are asymptomatic or exhibit mild symptoms despite high viral loads suggesting a key role for the acute phase innate immune response in limiting the damage and clearing the virus. Therefore, it is important to understand the early phase response to SARS-CoV-2 infection in such patients to devise strategies for clinical management of the disease. Our study shows the kinetics of immune mediators in the serum samples collected from hospitalized COVID-19 patients with mild symptoms. We further characterize a virus isolate from one of these patients and demonstrate its effect on epithelial barrier functions and show that zinc was capable of inhibiting SARS-CoV-2 infection under these conditions. Our results suggest a key role for the innate immune responses in the early phase of infection in mitigating clinical symptoms, clearing the virus and recovery from illness and suggest an antiviral role for zinc in COVID-19 infection.

Diagnostic Accuracy of FDA Authorized Serology Tests to Detect SARS-CoV-2 Antibodies: A Systematic Review and Meta-analysis

ImportanceSerology tests are diagnostic and complementary to molecular tests during the COVID-19 pandemic. ObjectiveTo evaluate the diagnostic accuracy of FDA authorized serology tests for the detection of SARS-CoV-2 infection. Data sourcesA search of MEDLINE, SCOPUS, CINAHL Plus, and EMBASE up to April 4, 2020, was performed to identify studies using the "COVID 19 testing" and "meta-analysis." FDA website was accessed for the list of tests for emergency use authorization (EUA). Study SelectionManufacturer reported serology tests published in the FDA website were selected. Two reviewers independently assessed the eligibility of the selected reports. Data extraction and synthesisThe meta-analysis was performed in accordance with the PRISMA guidelines. A bivariate analysis using the "random-effects model" was applied for pooled summary estimates of sensitivity, specificity, and the summary receiver operating characteristic curves. Main outcomes and measuresThe primary outcome was the diagnostic accuracy of the serology test for detecting SARS-CoV-2 infection. Subgroup analysis of the diagnostic accuracy with lag time between symptom onset and testing were studied. ResultsSeven manufacturer listed reports were included. The pooled sensitivity was 87% (95% CI, 78% - 93%), the pooled specificity was 100% (95% CI, 97% - 100%), and the area under the hierarchical summary receiver operating characteristic curve was 0.97. At [≤] 7 days, sensitivity was 44% (95% CI, 21% - 70%), and for 8-14 days, sensitivity was 84% (95% CI, 67 % - 94%).For blood draws [≥] 15 days after the onset of symptoms, sensitivity was 96% (95% CI, 93% - 98%). Heterogeneity was substantial, and the risk of bias was low in this analysis. Conclusions and relevanceFDA authorized serology tests demonstrate high diagnostic accuracy for SARS-CoV-2 infection (certainty of evidence: moderate). There is a wide variation in the test accuracy based on the duration between the onset of symptoms and the tests (certainty of evidence: low). Key- points QuestionsWhat is the pooled diagnostic accuracy of FDA authorized serology tests to detect SARS-CoV-2 antibodies? FindingsIn this systematic review and meta-analysis of seven reports from FDA authorized serology tests to detect antibodies against SARS-CoV2 antibodies (3336 patients/ samples) pooled sensitivity was 87%, and pooled specificity was almost 100%. There was a wide variation in test performance based on the duration between the onset of symptoms and the tests. MeaningFDA authorized tests are highly accurate to detect antibodies against SARS-CoV-2 antibodies if tests are performed under a similar condition, as presented in the original report. There is a wide variation in the test performance based on the time interval between the onset of symptoms to the tests.

Nature and dimensions of the cytokine storm and its attenuation by convalescent plasma in severe COVID-19

In a randomized control trial on convalescent plasma therapy (CPT) in severe COVID-19, we characterized the nature, in terms of abundance of forty eight cytokines, and dimensions, in terms of their interrelationships, of the hyper-immune activation-associated cytokine storm in patients suffering from acute respiratory distress syndrome. We found reduced plasma level of the chemokine MCP3 to be a key correlate for clinical improvement, irrespective of therapeutic regimen. We also identified an anti-inflammatory role of CPT independent of its neutralizing antibody content, and a linear regression analysis revealed that neutralizing antibodies as well as the anti-inflammatory effect of CPT both contribute to marked immediate reductions in hypoxia, as compared to patients on standard therapy.

SARS-CoV-2 antibody seroprevalence and stability in a tertiary care hospital-setting

BackgroundSARS-CoV-2 infection has caused 64,469 deaths in India, with 7, 81, 975 active cases till 30th August 2020, lifting it to 3rd rank globally. To estimate the burden of the disease with time it is important to undertake a longitudinal seroprevalence study which will also help to understand the stability of anti SARS-CoV-2 antibodies. Various studies have been conducted worldwide to assess the antibody stability. However, there is very limited data available from India. Healthcare workers (HCW) are the frontline workforce and more exposed to the COVID-19 infection (SARS-CoV-2) compared to the community. This study was conceptualized with an aim to estimate the seroprevalence in hospital and general population and determine the stability of anti SARS-CoV-2 antibodies in HCW. MethodsStaff of a tertiary care hospital in Delhi and individuals visiting that hospital were recruited between April to August 2020. Venous blood sample, demographic, clinical, COVID-19 symptoms, and RT-PCR data was collected from all participants. Serological testing was performed using the electro-chemiluminescence based assay developed by Roche Diagnostics, in Cobas Elecsys 411. Seropositive participants were followed- upto 83 days to check for the presence of antibodies. ResultsA total of 780 participants were included in this study, which comprised 448 HCW and 332 individuals from the general population. Among the HCW, seroprevalence rates increased from 2.3% in April to 50.6% in July. The cumulative prevalence was 16.5% in HCW and 23.5% (78/332) in the general population with a large number of asymptomatic individuals. Out of 74 seropositive HCWs, 51 were followed-up for the duration of this study. We observed that in all seropositive cases the antibodies were sustained even up to 83 days. ConclusionThe cumulative prevalence of seropositivity was lower in HCWs than the general population. There were a large number of asymptomatic cases and the antibodies developed persisted through the duration of the study. More such longitudinal serology studies are needed to better understand the antibody response kinetics.

Integrated genomic view of SARS-CoV-2 in India

India first detected SARS-CoV-2, causal agent of COVID-19 in late January-2020, imported from Wuhan, China. March-2020 onwards; importation of cases from rest of the countries followed by seeding of local transmission triggered further outbreaks in India. We used ARTIC protocol based tiling amplicon sequencing of SARS-CoV-2 (n=104) from different states of India using a combination of MinION and MinIT from Oxford Nanopore Technology to understand introduction and local transmission. The analyses revealed multiple introductions of SARS-CoV-2 from Europe and Asia following local transmission. The most prevalent genomes with patterns of variance (confined in a cluster) remain unclassified, here, proposed as A4-clade based on its divergence within A-cluster. The viral haplotypes may link their persistence to geo-climatic conditions and host response. Despite the effectiveness of non-therapeutic interventions in India, multipronged strategies including molecular surveillance based on real-time viral genomic data is of paramount importance for a timely management of the pandemic.