Indian journal of medical microbiology
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Indian J Med Microbiol · Oct 2021
Relevance of immune response and vaccination strategies of SARS-CoV-2 in the phase of viral red queen dynamics.
Following a relatively mild first wave of coronavirus disease 2019 (COVID-19) in India, a deadly second wave of the pandemic overwhelmed the healthcare system due to the emergence of fast-transmitting SARS-CoV-2 genetic variants. The emergence and spread of the B.1.617.2/Delta variant considered to be driving the devastating second wave of COVID-19 in India. Currently, the Delta variant has rapidly overtaken the previously circulating variants to become the dominant strain. Critical mutations in the spike/RBD region of these variants have raised serious concerns about the virus's increased transmissibility and decreased vaccine effectiveness. As a result, significant scientific and public concern has been expressed about the impact of virus variants on COVID-19 vaccines. ⋯ Phylogenetic analysis of SARS-CoV-2 isolates circulating in India suggests the emergence and spread of B.1.617 variant. The immunogenicity of currently approved vaccines indicates that the majority of vaccines elicit an antibody response and some level of protection. According to current data, vaccines in the pre-fusion configuration (2p substitution) have an advantage in terms of nAb titer, but the duration of vaccine-induced immunity, as well as the role of T cells and memory B cells in protection, remain unknown. Since vaccine efficacy on virus variants is one of the major factors to be considered for achieving herd immunity, existing vaccines need to be improved or effective next-generation vaccines should be developed to cover the new variants of the virus.
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Indian J Med Microbiol · Jul 2021
Evaluating the efficiency of specimen (sample) pooling for real-time PCR based diagnosis of COVID-19.
This study is aims at evaluating the efficacy and sensitivity of specimen pooling for testing of SARS-CoV-2 virus to determine the accuracy, resource savings, and identification of borderline positive cases without impacting the accuracy of the testing. ⋯ Pooled sample RT- PCR analysis strategies can save substantial resources and time for COVID-19 mass testing in comparison with individual testing without compromising the quality of outcome of the test. In particular, the pooled sample approach can facilitate mass screening in the early asymptomatic stages of COVID-19 infections.
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Indian J Med Microbiol · Jul 2020
Comparative StudyComparison of two real-time polymerase chain reaction assays for the detection of severe acute respiratory syndrome-CoV-2 from combined nasopharyngeal-throat swabs.
In the absence of effective treatment or vaccine, the current strategy for the prevention of further transmission of severe acute respiratory syndrome (SARS) CoV-2 (COVID-19) infection is early diagnosis and isolation of cases. The diagnosis of SARS-CoV-2 is done by detecting viral RNA in the nasopharyngeal and throat swabs by real-time polymerase chain reaction (PCR). Many commercial assays are now available for performing the PCR assay. ⋯ The results highlight the need for careful evaluation of commercial kits before being deployed for screening of COVID-19 infections.
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Indian J Med Microbiol · Jul 2020
Review Meta AnalysisEffect of chloroquine and hydroxychloroquine on COVID-19 virological outcomes: An updated meta-analysis.
As anti-malarial drugs have been found to inhibit Corona viruses in vitro, studies have evaluated the effect of these drugs inCOVID-19 infection. We conducted an updated meta-analysis of clinical trials and observational studies published till June 2020. Patients with reverse transcription polymerase chain reaction (RT-PCR) confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19) infection were included. ⋯ To conclude, CQ/HCQ does not affect the time to virological cure compared to usual/standard of care in COVID-19 infection. Recurrent infection in a smaller number of patients was noted in the CQ/HCQ group. As the evidence generated was of "very low-quality/certainty)", large good quality studies are needed to confirm the present findings.