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Background: Identification of SARS-CoV-2 positive patients with rapid and cost-effective test methods is the key for isolating infected individuals, interrupting the transmission chain, and thus, containment of the CoVID-19 disease. In this regard, Rapid Antigen Test (RAT) plays an important role at point of care testing but the low sensitivity attributing towards escape of positive cases is reported as a major disadvantage of RAT which led us to evaluate a RAT kit among symptomatic and asymptomatic individuals suspected of CoVID-19., Methods: We analyzed 329 parallel nasopharyngeal swabs for RAT (Zydus Cadila, India) at the point of collection in a hospital-based facility and RealTime RT-PCR in the laboratory. The performance parameters were analyzed by evaluating the specificity, sensitivity, Negative Predictive Value (NPV), Positive Predictive Value (PPV), and Kappa coefficient., Results: The sensitivity and specificity were found to be 75.17% and 98.89% respectively. Positive Predictive value was 98.25% and the negative predictive value was 82.79%. The accuracy between the two techniques was found to be 88.14% with a kappa coefficient of 0.756 (SE: 0.036 and CI at 95%: 0.686 to 0.826) with a good strength of agreement (0.61-0.80) between the two testing techniques. Among the false-negative cases, 22 (59.5%) were asymptomatic having the Cycle Threshold (Ct) range 27 to 32.9 including 12 cases with a history of close contact with the known positive cases (i.e. household contact). The remaining 15 cases (40.5%) were symptomatic having low to moderate Ct values., Conclusion: It is observed from the results that the false negative result for symptomatic individuals is a matter of concern as it was noted in 4 cases of our study subjects who required hospitalisation later. Also the positives among asymptomatic contacts are important from epidemiological point of view for isolation and curtailing the infection from spreading in a community. These results support the fact that RAT showing sensitivity below 80% can be used for mass screening purposes with provision for additional testing in case of false negative with symptomatic individuals. Also false-negative results should be interpreted cautiously considering the epidemiological link as well as the clinical condition of the patients., (© 2023. The Author(s).)

In this study, we attempted to record the breakthrough cases reported through passive and voluntary reporting at various healthcare facilities from different districts of Odisha, their clinical presentation, requirement of hospitalization postinfection, and antibody titer against spike antigen. Nasopharyngeal swab and serum samples alongwith demographic, clinical presentation and requirement of hospitalization postinfection were collected from vaccinated individuals through passive and voluntary reporting to various healthcare facilities of Odisha state to detect the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus infection and quantitative estimation of antibody titers. A total of 274 samples were found to be positive after 14 days of receiving complete doses of the vaccines. More than 83.2% of the individuals were found to be symptomatic with 9.9% of those required hospitalization. The seropositivity in individuals receiving Covishield (96.7%) was significantly higher than in Covaxin (77.1%). Hospitalized patients were having less median antibody titers than individuals in home isolation. The median age for breakthrough infection among the referred cases was 47.0 years (interquartile range [IQR]: 28.0) with a significantly older age group among Covishield recipients. The median spike receptor binding domain IgG titer values for Covaxin and Covishield recipients were 213.5 AU/ml (IQR: 537.5) and 647.5 AU/ml (IQR: 1645.1), respectively. The results reported here highlight the need for systematic data capture for the breakthrough infections to monitor the emergence of any vaccine escape variants and to plan the next steps in the coronavirus disease-19 (COVID-19) vaccine development by understanding the link between clinical protection and measured immunity against SARS-CoV-2 infection., (© 2021 Wiley Periodicals LLC.)

We retrospectively analysed the swab samples tested for COVID-19 from 7 March 2020 to 17 August 2021 at the Indian Council of Medical Research-Regional Medical Research Centre, Bhubaneswar, Odisha. 553 763 nasopharyngeal swabs were collected from individuals suspected with COVID-19 in Odisha state. 75 190 (13.6%) samples were positive by reverse transcription-PCR. There were 5988 (8%) cases in children and young people under 18 years old. Odisha reported 996 153 COVID-19 cases which resulted in 6985 deaths in adults and 36 in children and young people under 18 years old., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Vaccines are available worldwide to combat coronavirus disease-19 (COVID-19). However, the long-term kinetics of the vaccineinduced antibodies against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have not been sufficiently evaluated. This study was performed to investigate the persistence and dynamicity of BBV-152 (Covaxin)- and AZD1222 (Covishield)-induced immunoglobulin-G (IgG) antibodies over the year and neutralizing antibodies’ status after 1-month of booster dose. Materials and methods: This 52-week longitudinal cohort study documented antibody persistence and neutralizing antibodies status among 304 healthcare workers (HCWs) from six hospitals and research facilities in Odisha, enrolled during January 2021 and continued till March 2022. IgG antibodies against spike receptor-binding domain (RBD) of SARS-CoV-2 were quantified in an automated chemiluminescence immune assay-based (CLIA) platform and a surrogate virus neutralization test (sVNT) was performed by enzyme-linked immunosorbent assay (ELISA). Results: Among these 304 HCWs vaccinated with double doses, 154 HCWs (50.66%) were Covaxin recipients and the remaining 150 (49.34%) were Covishield recipients. During the follow-ups for seven times, a total of 114 participants were identified as vaccine breakthrough cases. In 190 noninfected HCWs, the median antibody titer was significantly waned from DD2 to DD10, both for Covaxin (231.8 vs. 42.7 AU/ml) and Covishield (1,884.6 vs. 369.2 AU/ml). No statistically significant differences in antibody titers were observed based on age, gender, comorbidities, and blood groups. The median inhibition activity of sVNT increased from 23.8 to 91.3% for Covaxin booster recipients and from 41.2 to 96.0% for Covishield booster recipients. Among 146 booster dose recipients, 48 were breakthrough cases after booster and all were contracted by the omicron variant. Conclusion: This year-long follow-up study found a 7- and 5-fold antibody waning in Covaxin and Covishield recipients, respectively, without any breakthrough infection history. However, individuals with booster breakthrough had mild symptoms and did not require hospital admission. The data also indicate the possible escape of omicron variants despite the presence of vaccine-induced neutralizing antibodies. [ABSTRACT FROM AUTHOR]

In this study, we attempted to record the breakthrough cases reported through passive and voluntary reporting at various healthcare facilities from different districts of Odisha, their clinical presentation, requirement of hospitalization postinfection, and antibody titer against spike antigen. Nasopharyngeal swab and serum samples alongwith demographic, clinical presentation and requirement of hospitalization postinfection were collected from vaccinated individuals through passive and voluntary reporting to various healthcare facilities of Odisha state to detect the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) virus infection and quantitative estimation of antibody titers. A total of 274 samples were found to be positive after 14 days of receiving complete doses of the vaccines. More than 83.2% of the individuals were found to be symptomatic with 9.9% of those required hospitalization. The seropositivity in individuals receiving Covishield (96.7%) was significantly higher than in Covaxin (77.1%). Hospitalized patients were having less median antibody titers than individuals in home isolation. The median age for breakthrough infection among the referred cases was 47.0 years (interquartile range [IQR]: 28.0) with a significantly older age group among Covishield recipients. The median spike receptor binding domain IgG titer values for Covaxin and Covishield recipients were 213.5 AU/ml (IQR: 537.5) and 647.5 AU/ml (IQR: 1645.1), respectively. The results reported here highlight the need for systematic data capture for the breakthrough infections to monitor the emergence of any vaccine escape variants and to plan the next steps in the coronavirus disease‐19 (COVID‐19) vaccine development by understanding the link between clinical protection and measured immunity against SARS‐CoV‐2 infection. [ABSTRACT FROM AUTHOR]

Background & objectives: Public health and diagnostic laboratories are facing huge sample loads for COVID-19 diagnosis by real-time reverse transcription-polymerase chain reaction (RT-PCR). High sensitivity of optimized real-time RT-PCR assays makes pooled testing a potentially efficient strategy for resource utilization when positivity rates for particular regions or groups of individuals are low. We report here a comparative analysis of pooled testing for 5- and 10-sample pools by real-time RT-PCR across 10 COVID-19 testing laboratories in India. Methods: Ten virus research and diagnostic laboratories (VRDLs) testing for COVID-19 by real-time RT-PCR participated in this evaluation. At each laboratory, 100 nasopharyngeal swab samples including 10 positive samples were used to create 5- and 10-sample pools with one positive sample in each pool. RNA extraction and real-time RT-PCR for SARS-CoV-2-specific E gene target were performed for individual positive samples as well as pooled samples. Concordance between individual sample testing and testing in the 5- or 10-sample pools was calculated, and the variation across sites and by sample cycle threshold (Ct) values was analyzed. Results: A total of 110 each of 5- and 10-sample pools were evaluated. Concordance between the 5-sample pool and individual sample testing was 100 per cent in the Ct value ≤30 cycles and 95.5 per cent for Ctvalues ≤33 cycles. Overall concordance between the 5-sample pooled and individual sample testing was 88 per cent while that between 10-sample pool and individual sample testing was 66 per cent. Although the concordance rates for both the 5- and 10-sample pooled testing varied across laboratories, yet for samples with Ct values ≤33 cycles, the concordance was ≥90 per cent across all laboratories for the 5-sample pools. Interpretation & conclusions: Results from this multi-site assessment suggest that pooling five samples for SARS-CoV-2 detection by real-time RT-PCR may be an acceptable strategy without much loss of sensitivity even for low viral loads, while with 10-sample pools, there may be considerably higher numbers of false negatives. However, testing laboratories should perform validations with the specific RNA extraction and RT-PCR kits in use at their centres before initiating pooled testing. [ABSTRACT FROM AUTHOR]

Pooled testing for COVID-19 diagnosis by real-time RT-PCR: A multi-site comparative evaluation of 5- & 10-sample pooling. This suggestion is based on the experiments conducted by the researchers in their laboratory. While agreeing with our findings, the researchers have suggested that the RT-PCR kit cut-offs should be adjusted by adding four cycles to the CT cut-off recommended by the manufacturer wherever pooled sample testing is being undertaken. [Extracted from the article]