ABSTRACT
BackgroundWe conducted a repeat serosurvey in Delhi, India to estimate the seroprevalence of SARS-CoV-2 in the general population and compare the antibody prevalence in the vaccinated and non-vaccinated groups. MethodsThis cross-sectional study was conducted from September 24 to October 14 2021 in 280 wards of Delhi among 27811 participants selected through a multistage sampling technique with housing settlement based stratification. The SARS-CoV-2 immunoglobulin (IgG) antibodies were screened with the VITROS(R) (Ortho Clinical Diagnostics, Raritan, NJ, USA) assay (90% sensitivity, 100% specificity). ResultsA total of 24895 (89.5%) samples were seropositive. The crude seroprevalence was 87.99% (95% CI 89.1, 89.8), weighted for age and sex was 88% (95% CI 87.6, 88.4), and after adjustment of assay performance was estimated as 97.5% (95% CI 97.0, 98.0). The weighted seroprevalence in the 11 districts ranged from 84.9% (South-West district) to 90.8% (East district) Females in all the age-groups (<18, 18-49 and [≥]50) had significantly higher odds of seropositivity (p<0.001). On adjusted analysis, the odds of seroconversion in the participants vaccinated with at-least one dose of either Covid-19 vaccine (Covishield/Covaxin) was more than four times compared to the unvaccinated (aRR 4.2 (3.8, 4.6)). The seroprevalence was also comparable among the complete and partially vaccinated subgroups for both vaccines (Table 4). Most (86.8%) seropositive individuals had a SARS-CoV-2 signal/cut-off [≥]4.0 except in children O_TBL View this table: org.highwire.dtl.DTLVardef@1482d5forg.highwire.dtl.DTLVardef@19ab8a1org.highwire.dtl.DTLVardef@cf675dorg.highwire.dtl.DTLVardef@8b427aorg.highwire.dtl.DTLVardef@b96a54_HPS_FORMAT_FIGEXP M_TBL O_FLOATNOTable 4.C_FLOATNO O_TABLECAPTIONVaccination status and seroprevalence of antibodies to SARS-CoV-2, Delhi, September-October 2021* C_TABLECAPTION C_TBL ConclusionsWe observed IgG antibodies against SARS-CoV-2 in most of the general population of Delhi with likely higher antibody titres in the vaccinated compared to the unvaccinated groups.
ABSTRACT
We conducted this study to estimate seroprevalence of neutralizing antibodies in the general population and to further correlate it with the IgG SARS-CoV-2 IgG levels. This present cross-sectional analysis was conducted as a sequel to a state level community-based seroepidemiological study in Delhi, India. A total of 2564 seropositive samples were selected from 25622 seropositive samples through simple random sampling. Neutralizing capacity was estimated by performing a surrogate virus neutralization test with the sVNT (GenScript) assay. Neutralizing antibody against the SARS-CoV-2 virus was operationally considered as detected when the signal inhibition was [≥]30%. A total of 2233 (87.1%, 95% C.I. 85.7, 88.3) of the 2564 SARS-CoV-2 seropositive samples had detectable neutralizing antibodies. On bi-variate analysis but not on adjusted analysis, Covid-19 vaccination showed a statistically significant association with the presence of neutralizing antibodies (p<0.001). The signal/ cut off (S/CO) of SARS-CoV-2 IgG ranged from 1.00 to 22.8 (median 11.40). In samples with S/CO [≥]4.00, the neutralizing antibodies ranged from 94.5 to 100%, while in samples with S/CO <4.00, it ranged from 52.0 to 79.2%. The neutralizing antibody seroprevalence strongly correlated with the S/CO range (r=0.62, p=0.002). In conclusion, in populations with high SARS-CoV-2 seroprevalence, neutralizing antibodies are generated in nearly 9 of 10 seropositive individuals.
ABSTRACT
BackgroundThere is a prolonged RT-PCR positivity seen in COVID-19 infected patients up to 2-3 months. We aim to investigate the presence of viral particles inside Extracellular vesicles (EV) and its role in underlying liver disease patients. MethodsSARS CoV2 nasal RT-PCR positive n=78 {n=24(66.6%) chronic liver disease (CLD); n=52 (81.3%) non-liver disease} were studied. SARS CoV2 patients were also followed up for day (d) 7, 14 and 28. Extracellular vesicles were isolated using differential ultracentrifugation. SARS CoV2 RNA was measured using qRT-PCR by Altona Real Star kit. ResultsIn baseline RT-PCR positive patients, SARS-CoV2 RNA inside the EV was present in 64/74 (82%) patients with comparable viral load between VTM and EV (mean 1CT - 0.033{+/-}0.005 vs. 1CT - 0.029{+/-}0.014, p=ns). On follow-up at day 7, of the 24 patients negative for COVID19, 10 (41%) had persistence of virus in the EV (1CT - 0.028{+/-}0.004) and on day 14, 14 of 40 (35%) negative RT-PCR had EVs with SARS CoV2 RNA (1CT - 0.028{+/-}0.06). The mean viral load decreased at day7 and day14 in nasal swab from baseline (p=0.001) but not in EV. SARS-CoV2 RNA otherwise undetectable in plasma, was found to be positive in EV in 12.5% of COVID19 positive patients. Interestingly, significantly prolonged and high viral load was found in EV at day 14 in CLD-COVID19 patients compared to COVID19 alone (p=0.002). The high cellular injury was seen in CLD-COVID19 infected patients with significant high levels of EV associated with endothelial cells and hepatocytes than COVID19 alone (p=0.004; 0.001). ConclusionIdentification of SARS-CoV2 RNA in EV, in RT-PCR negative patients indicates persistence of infection for and likely recurrence of the infection. EV associated RNA may determine the clinical course of subjects with undetectable SARS-CoV2 virus and this may also have relevance in management of chronic liver disease patients.
ABSTRACT
RationaleCOVID-19 is an acute infectious disease caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Human surfactant protein D (SP-D) is known to interact with spike protein of SARS-CoV, but its immune-surveillance against SARS-CoV-2 is not known. ObjectiveThis study aimed to examine the potential of a recombinant fragment of human SP-D (rfhSP-D) as an inhibitor of replication and infection of SARS-CoV-2. MethodsrfhSP-D interaction with spike protein of SARS-CoV-2 and hACE-2 receptor was predicted via docking analysis. The inhibition of interaction between spike protein and ACE-2 by rfhSP-D was confirmed using direct and indirect ELISA. The effect of rfhSP-D on replication and infectivity of SARS-CoV-2 from clinical samples was studied by measuring the expression of RdRp gene of the virus using qPCR. Measurements and Main ResultsIn-silico interaction studies indicated that three amino acid residues in the RBD of spike of SARS-CoV-2 were commonly involved in interacting with rfhSP-D and ACE-2. Studies using clinical samples of SARS-CoV-2 positive cases (asymptomatic, n=7 and symptomatic, n=8 and negative controls n=15) demonstrated that treatment with 5M rfhSP-D inhibited viral replication by ~5.5 fold and was more efficient than Remdesivir (100 M). Approximately, a 2-fold reduction in viral infectivity was also observed after treatment with 5M rfhSP-D. ConclusionsThese results conclusively demonstrate that the calcium independent rfhSP-D mediated inhibition of binding between the receptor binding domain of the S1 subunit of the SARS-CoV-2 spike protein and human ACE-2, its host cell receptor, and a significant reduction in SARS-CoV-2 infection and replication in-vitro.
ABSTRACT
BackgroundRespiratory viral infections are an important cause of acute respiratory tract infections. They are caused by both Influenza and non influenza viruses. Respiratory viral infections are known to be associated with severe clinical outcome especially in the critically ill. A constant surveillance is needed for early etiological identification which can help in timely and appropriate management and will further help in prevention of indiscriminate use of antibiotics in patients with viral etiology. MethodsIn this retrospective study, clinical records of all adult liver disease patients with clinically confirmed ARI, whose request for respiratory viral testing were received in the virology laboratory during September 2016 - March 2019 were reviewed. Respiratory viruses were identified by real time PCR on FilmArray 2.0 instrument (BioFire Diagnostics, Utah, USA) using Respiratory panel as per the manufacturers instructions. ResultsOf the 603 patients of liver disease with clinically confirmed influenza like illness, over all incidence of respiratory viral infection was 24.3% (n= 147). Infections by non-influenza viruses (87, 59.1%) were more than influenza group of viruses. Mortality was higher in non influenza group (43, 49.4%) as compared to influenza (24, 40%) [p=0.015] being maximum in Rhinovirus, 22 (32.8%). Two peaks were observed in both influenza and non influenza groups, first in the months of January and February and the other one in August and October. ConclusionWith the emergence of SARS-CoV-2 it has now become imperative for a constant surveillance of the non influenza viruses for early etiological identification of the respiratory viral infection for proper and timely management in the critically ill. HighlightsO_LIPatients with liver cirrhosis having Respiratory viral infections have a poor outcome in terms of morbidity and mortality. C_LIO_LIMortality associated with non influenza viruses (NIV) is more as compared to influenza virus infections. C_LIO_LICOVID-19 pandemic and higher mortality in NIVs warrants a constant monitoring of respiratory viral infections. C_LI
ABSTRACT
Rapid diagnosis and precise prognostication of SARS-CoV-2 infection remains a major challenge. A multi-omic approach was adopted, and in the discovery phase, global proteome/metaproteome/metabolome were analysed in the respiratory specimens of SARS-CoV-2 positive [n=20], negative [n=20], and H1N1 positive [n=5] cases. We identified MX1 (MX Dynamin Like GTPase 1) and WARS (Tryptophan--tRNA ligase) as clues to viral diagnosis and validated in 200 SARS-CoV-2 suspects. MX1 >30pg/ml and WARS >25ng/ml segregated virus positives patients [(AUC=94%CI(0.91-0.97)]. Distinct increase in SARS-CoV-2 induced immune activation, metabolic reprograming and a decrease in oxygen transport, wound healing, fluid regulation, vitamin and steroid metabolism was seen (p<0.05). Multi-omics profiling correlated with viraemia and segregated asymptomatic COVID-19 patients. Additionally, the multiomics approach identified increased respiratory pathogens [Burkholderiales, Klebsiella pneumonia] and decreased lactobacillus salivarius (FDR<0.05, p<0.05) in COVID-19 specimens. ConclusionNovel proteins [MX1 and WARS] can rapidly and reliably diagnose SARS-CoV-2 infection and identify asymptomatic and mild disease.
ABSTRACT
BackgroundCorona virus disease 2019 (COVID-19) which initially started as a cluster of pneumonia cases in the Wuhan city of China has now become a full blown pandemic. Timely diagnosis of COVID-19 is the key in containing the pandemic and breaking the chain of transmission. In low and middle income countries availability of testing kits has become the major bottle neck in testing. Novel methods like pooling of samples are the need of the hour. MethodExtracted RNA samples were randomly placed in pools of 8 on a 96 well plate. Both individual RNA (ID) and pooled RNA RT-qPCR for the screening E gene were done in the same plate and the positivity for the E gene was seen. ResultsThe present study demonstrated that pool testing with 8 RNA samples can easily detect even up to a single positive sample with Ct value as high as 38. The present study also showed that the results of pool testing is not affected by number of positive samples in a pool. ConclusionPooling of 8 RNA samples can reduce the time and expense by one eighth, and can help expand diagnostic capabilities, especially during constrained supply of reagents and PCR kits for the diagnosis of SARS-CoV-2 infection.
