Evaluation of RdRp & ORF-1b-nsp14-based real-time RT-PCR assays for confirmation of SARS-CoV-2 infection: An observational study

Research progress of severe acute respiratory syndrome coronavirus 2 on aerosol collection and detection

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019 has negatively affected people's lives and productivity. Because the mode of transmission of SARS-CoV-2 is of great concern, this review discusses the sources of virus aerosols and possible transmission routes. First, we discuss virus aerosol collection methods, including natural sedimentation, solid impact, liquid impact, centrifugal, cyclone and electrostatic adsorption methods. Then, we review common virus aerosol detection methods, including virus culture, metabolic detection, nucleic acid-based detection and immunology-based detection methods. Finally, possible solutions for the detection of SARS-CoV-2 aerosols are introduced. Point-of-care testing has long been a focus of attention. In the near future, the development of an instrument that integrates sampling and output results will enable the real-time, automatic monitoring of patients.

Environmental surveillance of SARS-CoV-2 in municipal wastewater to monitor COVID-19 status in urban clusters in Malaysia

Wastewater monitoring for SARS-CoV-2 has attracted considerable attention worldwide to complement the existing clinical-based surveillance system. In this study, we report our first successful attempt to prove the circulation of SARS-CoV-2 genes in Malaysian urban wastewater. A total of 18 wastewater samples were obtained from a regional sewage treatment plant that received municipal sewage between February 2021 and May 2021. Using the quantitative PCR assay targeting the E and RdRp genes of SARS-CoV-2, we confirmed that both genes were detected in the raw sewage, while no viral RNA was found in the treated sewage. We were also able to show that the trend of COVID-19 cases in Kuala Lumpur and Selangor was related to the changes in SARS-CoV-2 RNA levels in the wastewater samples. Overall, our study highlights that monitoring wastewater for SARS-CoV-2 should help local health professionals to obtain additional information on the rapid and silent circulation of infectious agents in communities at the regional level.

SARS-CoV-2 variants: Impact on biological and clinical outcome

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that was first identified in December 2019, in Wuhan, China was found to be the etiological agent for a novel respiratory infection that led to a Coronavirus Induced Disease named COVID-19. The disease spread to pandemic magnitudes within a few weeks and since then we have been dealing with several waves across the world, due to the emergence of variants and novel mutations in this RNA virus. A direct outcome of these variants apart from the spike of cases is the diverse disease presentation and difficulty in employing effective diagnostic tools apart from confusing disease outcomes. Transmissibility rates of the variants, host response, and virus evolution are some of the features found to impact COVID-19 disease management. In this review, we will discuss the emerging variants of SARS-CoV-2, notable mutations in the viral genome, the possible impact of these mutations on detection, disease presentation, and management as well as the recent findings in the mechanisms that underlie virus-host interaction. Our aim is to invigorate a scientific debate on how pathogenic potential of the new pandemic viral strains contributes toward development in the field of virology in general and COVID-19 disease in particular.

Multi-Cellular Immunological Interactions Associated With COVID-19 Infections

To rapidly prognosticate and generate hypotheses on pathogenesis, leukocyte multi-cellularity was evaluated in SARS-CoV-2 infected patients treated in India or the United States (152 individuals, 384 temporal observations). Within hospital (<90-day) death or discharge were retrospectively predicted based on the admission complete blood cell counts (CBC). Two methods were applied: (i) a "reductionist" one, which analyzes each cell type separately, and (ii) a "non-reductionist" method, which estimates multi-cellularity. The second approach uses a proprietary software package that detects distinct data patterns generated by complex and hypothetical indicators and reveals each data pattern's immunological content and associated outcome(s). In the Indian population, the analysis of isolated cell types did not separate survivors from non-survivors. In contrast, multi-cellular data patterns differentiated six groups of patients, including, in two groups, 95.5% of all survivors. Some data structures revealed one data point-wide line of observations, which informed at a personalized level and identified 97.8% of all non-survivors. Discovery was also fostered: some non-survivors were characterized by low monocyte/lymphocyte ratio levels. When both populations were analyzed with the non-reductionist method, they displayed results that suggested survivors and non-survivors differed immunologically as early as hospitalization day 1.

Rapid antigen detection kit for the diagnosis of SARS-CoV-2 - are we missing asymptomatic patients?

Purpose

To determine the utility, diagnostic accuracy, sensitivity, specificity, and negative predictive value of the laboratory based Covid-19 antigen detection test (Coris Bio- Concept, Gembloux, Belgium) for the diagnosis of SARS-CoV-2 in a tertiary care hospital among symptomatic and asymptomatic patients.

Methods

The nasopharyngeal swab samples were collected from the symptomatic patients and their contacts. The diagnostic accuracy of this antigen kit was determined in comparison to SARS-CoV-2 real-time reverse transcriptase (RT-PCR).

Results

A total of 825 patients fulfilling the inclusion criteria were included in the study; RT-PCR and antigen detection was performed simultaneously for 484 samples to determine the sensitivity and specificity of the test. The overall specificity and sensitivity was 99.32% and 71.96% respectively. Also, 3.7% of the asymptomatic patients who were negative by RAT were detected positive by RT-PCR.

Conclusion

This rapid antigen test (RAT) was sensitive in the symptomatic patients presenting during the initial phase of the illness. Since, majority of the SARS-CoV-2 patients are asymptomatic and considering the huge population, the testing strategy formulated by Indian Council of Medical Research (ICMR) at the national level was cost effective. Thus, Ag-RDTs could play a pivotal role in early diagnosis, policy making and surveillance of the SARS-CoV-2.

Detection of SARS-CoV-2 infection by RT-PCR test: factors influencing interpretation of results

In this current pandemic of coronavirus disease 2019 (COVID-19), prompt interventions in terms of early detection and clinical management along with isolation of positive cases is of utmost importance. This helps to limit not only the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections but also the morbidity and mortality associated with it. Different strategies for screening of COVID-19 in containment zones and non-containment areas include testing of symptomatic patients and their contacts in fever clinics, hospital-based testing, testing on demand and population-based screening. The choice of tests like reverse-transcription polymerase chain reaction (RT-PCR), rapid antigen testing (RAT) or antibody test depends upon these strategies and also the turnaround time. Currently, RT-PCR is considered the gold standard for COVID-19 detection. This commentary provides the insights and experiences on COVID-19 diagnosis by RT-PCR. The utility of this test is limited by several false positive, false negative and inconclusive results at early stages of infection, scarcity of reagents and lack of well-equipped labs including trained staff. Moreover, appropriate sample collection and transport, standard laboratory protocols, stringent quality control norms, good quality RNA extraction kits, PCR kits with suitable primers can help in improving accuracy of the test results. A careful assessment of clinical, radiological and molecular findings is required for identifying potential cases of COVID-19.

Clinical Profile, Viral Load, Maternal-Fetal Outcomes of Pregnancy With COVID-19: 4-Week Retrospective, Tertiary Care Single-Centre Descriptive Study

OBJECTIVE

The COVID-19 pandemic raises a major concern about its severity in pregnancy, maternal-fetal outcomes, and risk of vertical transmission. We report a retrospective descriptive study of the clinical course and maternal-fetal outcomes of pregnant women with COVID-19.

METHODS

This is a single-centre, retrospective study performed in a tertiary care hospital for pregnant women with COVID-19 in India. The medical records of all women who delivered in the COVID19 facility from May 5, 2020, to June 5, 2020, were reviewed independently. Data extracted from the records included demographic characteristics, obstetric details, comorbidities, disease severity, investigations, management, and information on neonates (birthweight, Apgar score, and perinatal complications).

RESULTS

Among 348 women tested for SARS-CoV-2, 57 women (16.3%) were confirmed as positive based on quantitative reverse transcriptase polymerase chain reaction of the nasopharyngeal specimen. Most women (45; 78.9%) had a mild infection with favourable maternal-fetal outcomes. Three maternal deaths were associated with comorbidities. Five neonates tested positive for SARS-CoV-2, remained hemodynamically stable, and were subsequently discharged.

CONCLUSIONS

A majority of pregnant women with COVID-19 had mild disease and recovered with good perinatal outcomes. Women with comorbidities may have an increased risk of severe morbidity and mortality. The cycle threshold signifying the viral load and degree of infectivity can modify management during pregnancy. Long-term outcomes and the potential mother-to-child vertical/horizontal transmission need further study.

Perspectives About Modulating Host Immune System in Targeting SARS-CoV-2 in India

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus induced disease-2019 (COVID-19), is a type of common cold virus responsible for a global pandemic which requires immediate measures for its containment. India has the world's largest population aged between 10 and 40 years. At the same time, India has a large number of individuals with diabetes, hypertension and kidney diseases, who are at a high risk of developing COVID-19. A vaccine against the SARS-CoV-2, may offer immediate protection from the causative agent of COVID-19, however, the protective memory may be short-lived. Even if vaccination is broadly successful in the world, India has a large and diverse population with over one-third being below the poverty line. Therefore, the success of a vaccine, even when one becomes available, is uncertain, making it necessary to focus on alternate approaches of tackling the disease. In this review, we discuss the differences in COVID-19 death/infection ratio between urban and rural India; and the probable role of the immune system, co-morbidities and associated nutritional status in dictating the death rate of COVID-19 patients in rural and urban India. Also, we focus on strategies for developing masks, vaccines, diagnostics and the role of drugs targeting host-virus protein-protein interactions in enhancing host immunity. We also discuss India's strengths including the resources of medicinal plants, good food habits and the role of information technology in combating COVID-19. We focus on the Government of India's measures and strategies for creating awareness in the containment of COVID-19 infection across the country.

Clinical profile, viral load, management and outcome of neonates born to COVID 19 positive mothers: a tertiary care centre experience from India

Despite rapidly evolving knowledge about COVID 19 infection, routes of perinatal COVID 19 transmission and viral load in mother neonate dyad remain uncertain. Data were analysed to describe the clinicodemographic profile and viral load in neonates born to COVID 19 positive mothers. Of 2947 deliveries, 69 mothers were COVID 19 positive (2.3%), with 1 abortion, 2 macerated stillbirths and 2 fresh stillbirths as pregnancy outcomes. Of 65 tested neonates, 10.7% (7) were confirmed COVID 19 positive by RTPCR (reverse transcriptase-polymerase chain reaction). Viral load (cycle threshold, Ct of E, RDRp) in neonates was comparable with the Ct reported from adults; however, neonates had milder clinical manifestations. All 7 neonates who tested positive for COVID 19 were subsequently discharged. Six of the 7 neonates were asymptomatic and 1 neonate needed respiratory support (indication being prematurity) which resolved after 48 h. Maternal and neonatal comparison of Ct of E and RdRp gene was statistically non-significant (25.97 vs 19.68, p = 0.34 and 26.5 vs 25.0, p = 0.84). Viral loads of mothers with COVID 19 positive neonates compared with mothers with COVID 19 negative neonates for E and RdRp gene were also statistically non-significant (25 vs 27.19, p = 0.63 and 19.6 vs 27.6, p = 0.08). The majority (93%) of neonates tested later than 48 h (roomed in with mother and breastfed) tested negative.Conclusion: The study supports milder manifestation in COVID 19 positive neonates. Risk of transmission from COVID 19 positive mother to neonate by rooming-in and breastfeeding is low. In this study on a limited number of neonates, maternal viral load was not found to be associated with the positivity status or severity of the illness of neonate. What is Known: • Neonates born to COVID 19 positive mothers are at risk of COVID 19 infection. What is New: • Risk of transmission of COVID 19 from mother to neonate, with rooming-in and breastfeeding, appears low. • In this study on a limited number of neonates, maternal viral load of COVID 19 (E and RdRp cycle thresholds) was not associated with severity of illness or COVID 19 positivity in neonates.

Deletion in the C-terminal region of the envelope glycoprotein in some of the Indian SARS-CoV-2 genome

The envelope glycoprotein (E) is the smallest structural component of SARS-CoVs; plays an essential role in the viral replication starting from envelope formation to assembly. The in silico analysis of 2086 whole genome sequences from India performed in this study provides the first observation on the extensive deletion of amino acid residues in the C-terminal region of the envelope glycoprotein in 34 Indian SARS-CoV-2 genomes. These amino acid deletions map to the homopentameric interface and PDZ binding motif (PBM) present in the C-terminal region of E protein as well as immediately after the reverse primer binding region as per Charité protocol in 26 of these genomes, hence, their detection through RT-qPCR may not be hampered and therefore E gene-based RT-qPCR would still detect these isolates. Eight genomes from the State of Odisha had deletion even in the primer binding site. It is possible that the deletions in the C-terminal region of E protein of these genomes are a result of adapting to a newer geographical area and host. The information on the clinical status was available only for 9 out of 34 cases and these were asymptomatic. However, further studies are indispensable to understand the functional consequences of amino acid deletion in the C terminal region of SARS-CoV-2 envelope protein in the viral pathogenesis and host adaptation.

Detection technologies and recent developments in the diagnosis of COVID-19 infection

COVID-19 is a disease caused by SARS-CoV-2 capable of causing mild to severe infections in humans. Since its first appearance in China in December 2019, the pandemic has spread rapidly throughout the world. Despite considerable efforts made to contain the disease, the virus has continued its prevalence in many countries with varying degrees of clinical manifestations. To contain this pandemic, collaborative approach involving accurate diagnosis, epidemiology, surveillance, and prophylaxis is essential. However, proper diagnosis using rapid technologies plays a crucial role. With increasing incidence of COVID-19 cases, the accurate and early detection of the SARS-CoV-2 is need of the hour for effective prevention and management of COVID-19 cases as well as to curb its spread. RT-qPCR assay is considered to be the gold standard for the early detection of virus, but this protocol has limited application to use as bedside test because of its technical complexity. To address these challenges, several POC assays have been developed to facilitate the COVID-19 diagnosis outside the centralized testing laboratories as well to accelerate the clinical decision making with a least turnaround time. Hence, in this report, we review different nucleic acid-based and serological techniques available for the diagnosis and effective prevention of COVID-19. KEY POINTS : • Provides comprehensive information on the different diagnostic tools available for COVID-19 • Nucleic acid based tests or antigen detection tests are used for diagnostic purpose • Accurate diagnosis is essential for the efficient management of COVID-19.

Novel coronavirus disease (COVID-19) pandemic: A recent mini review

The COVID-19, caused by a novel coronavirus, was declared as a global pandemic by WHO more than five months ago, and we are still experiencing a state of global emergency. More than 74.30 million confirmed cases of the COVID-19 have been reported globally so far, with an average fatality rate of almost 3.0%. Seven different types of coronaviruses had been detected from humans; three of them have resulted in severe outbreaks, i.e., MERS-CoV, SARS-CoV, and SARS-CoV-2. Phylogenetic analysis of the genomes suggests that the possible occurrence of recombination between SARS-like-CoVs from pangolin and bat might have led to the origin of SARS-CoV-2 and the COVID-19 outbreak. Coronaviruses are positive-sense, single-stranded RNA viruses and harbour a genome (30 kb) consisting of two terminal untranslated regions and twelve putative functional open reading frames (ORFs), encoding for non-structural and structural proteins. There are sixteen putative non-structural proteins, including proteases, RNA-dependent RNA polymerase, helicase, other proteins involved in the transcription and replication of SARS-CoV-2, and four structural proteins, including spike protein (S), envelope (E), membrane (M), and nucleocapsid (N). SARS-CoV-2 infection, with a heavy viral load in the body, destroys the human lungs through cytokine storm, especially in elderly persons and people with immunosuppressed disorders. A number of drugs have been repurposed and employed, but still, no specific antiviral medicine has been approved by the FDA to treat this disease. This review provides a current status of the COVID-19, epidemiology, an overview of phylogeny, mode of action, diagnosis, and possible treatment methods and vaccines.