Identification and Analysis of SARS-CoV-2 Mutation and Subtype using 2x tiled Primer Set with Oxford Nanopore Technologies Sequencing for Enhanced Variant Detection and Surveillance in Seoul, Korea (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a respiratory virus that contains RNA as its genetic material and has caused a global pandemic since its outbreak in 2020. This virus has many mutations, some of which can reduce the effectiveness of existing vaccines. Therefore, next-generation sequencing (NGS) is necessary to accurately identify new mutations. Current NGS analysis of SARS-CoV-2 uses the amplicon analysis method through a multiplex polymerase chain reaction. This study collected and validated RNA samples from patients who tested positive for SARS-CoV-2 from April to July 2022, and selected 613 samples for sequencing. The findings demonstrate the importance of long-read-based NGS analysis and 2x tiled primer set for identifying full SARS-CoV-2 genome sequence with new mutations and understanding the correlation between viral genotypes and patient characteristics for the effective management of SARS-CoV-2.

Moving toward a common goal via cross-sector collaboration: lessons learned from SARS to COVID-19 in Singapore.

BACKGROUND: The spread of COVID-19 has taken a toll on many countries and its healthcare system over the last two years. Governments have sought to mitigate the repercussions of the pandemic by implementing aggressive top-down control measures and introducing immense fiscal spending. Singapore is no exception to this trend. Owing to a whole-of-society approach, Singapore is still being lauded globally for its relatively successful record at controlling both community and trans-border spread. One notable effort by the Singapore government has taken place through its cross-sectoral collaborative partnerships with the private stakeholders behind the success. METHODS/RESULTS: In an attempt to better explain Singapore's robust yet strategic response to COVID-19, this study focuses on how the experience of the SARS outbreak has informed the government's collaborative efforts with other stakeholders in society, beyond mere transnational cooperation. Taking a comparative case study approach in the specific context of Singapore, we perform a content analysis of related government documents, mainstream newspaper articles, and academic journal articles in an inductive manner. By closely comparing two global healthcare outbreaks, we note four differences in approach. First, during the COVID-19 pandemic, Singapore has focused on securing sufficient essential healthcare resources with contingency plans to strengthen preparedness. Second, the government has actively harnessed the capacity of private entities to promote the resilience of the healthcare system and the community. Third, Singapore's management policies have been made not only in a top-down, centralized style during the initial response stage, but also with a greater proportion of bottom-up approaches, particularly as the pandemic trudges on. More interestingly, the multi-faceted repercussions of COVID-19 have gradually opened the door to a greater variety of collaborative partnerships in sectors beyond healthcare services. The participating stakeholders include, but are not limited to, local and international business actors, non-profit organizations, academia and other countries. Lastly, as the pandemic has continued, the Singapore government has managed outward to tap the expertise and knowledge of the private sector, in particular leveraging science and technology to improve control measures and putting supportive programs into practice. CONCLUSION: The evidence from our focused analyses demonstrates that the nature and scale of the COVID-19 pandemic produced more collaborative partnerships between the public and private sectors in Singapore as compared with the SARS outbreak. What is more, our findings offer evidence that through adaptive learning from the prior global healthcare outbreak, plus some trial and error during the initial phase of the ongoing pandemic, public- and private-sector partners, both in and outside of the healthcare service sector, have tended to "act alike," working together to achieve a common goal. Both have been socially responsible, providing public services to people in need to promote the rapid resilience of the community, and sharing the associated risks. Overall, this study has deep and wide implications for other governments and policy makers who are still struggling to maximize essential resources and minimize the negative impacts of the healthcare crisis.

Clinical epidemiological applicability of real-time polymerase chain reaction for COVID-19.

OBJECTIVES: Real-time polymerase chain reaction is currently used as a confirmatory test for coronavirus disease 2019 (COVID-19). The test results are interpreted as positive, negative, or inconclusive, and are used only for a qualitative classification of patients. However, the test results can be quantitated using threshold count (Ct) values to determine the amount of virus present in the sample. Therefore, this study investigated the diagnostic usefulness of Ct results through various quantitative analyzes, along with an analysis of clinical and epidemiological characteristics. METHODS: Clinical and epidemiological data from 4,642 COVID-19 patients in April 2021 were analyzed, including the Ct values of the RNA-dependent RNA polymerase (RdRp), envelope (E), and nucleocapsid (N) genes. Clinical and epidemiological data (sex, age, underlying diseases, and early symptoms) were collected through a structured questionnaire. A correlation analysis was used to examine the relationships between variables. RESULTS: All 3 genes showed statistically significant relationships with symptoms and severity levels. The Ct values of the RdRp gene decreased as the severity of the patients increased. Moreover, statistical significance was observed for the presence of underlying diseases and dyspnea. CONCLUSION: Ct values were found to be related to patients' clinical and epidemiological characteristics. In particular, since these factors are closely related to symptoms and severity, Ct values can be used as primary data for predicting patients' disease prognosis despite the limitations of this method. Conducting follow-up studies to validate this approach might enable using the data from this study to establish policies for preventing COVID-19 infection and spread.

Two-Year Health Outcomes in Hospitalized COVID-19 Survivors in China.

Importance: Relatively little is known about the persistence of symptoms in patients with COVID-19 for more than 1 year after their acute illness. Objective: To assess the health outcomes among hospitalized COVID-19 survivors over 2 years and to identify factors associated with increased risk of persistent symptoms. Design, Setting, and Participants: This was a longitudinal cohort study of patients who survived COVID-19 at 2 COVID-19-designated hospitals in Wuhan, China, from February 12 to April 10, 2020. All patients were interviewed via telephone at 1 year and 2 years after discharge. The 2-year follow-up study was conducted from March 1 to April 6, 2022. Statistical analysis was conducted from April 20 to May 5, 2022. The severity of disease was defined by World Health Organization guideline for COVID-19. Exposures: COVID-19. Main Outcomes and Measures: The main outcome was symptom changes over 2 years after hospital discharge. All patients completed a symptom questionnaire for evaluation of symptoms, along with a chronic obstructive pulmonary disease assessment test (CAT) at 1-year and 2-year follow-up visits. Results: Of 3988 COVID-19 survivors, a total of 1864 patients (median [IQR] age, 58.5 [49.0-68.0] years; 926 male patients [49.7%]) were available for both 1-year and 2-year follow-up visits. The median (IQR) time from discharge to follow-up at 2 years was 730 (719-743) days. At 2 years after hospital discharge, 370 patients (19.8%) still had symptoms, including 224 (12.0%) with persisting symptoms and 146 (7.8%) with new-onset or worsening of symptoms. The most common symptoms were fatigue, chest tightness, anxiety, dyspnea, and myalgia. Most symptoms resolved over time, but the incidence of dyspnea showed no significant change (1-year vs 2-year, 2.6% [49 patients] vs 2.0% [37 patients]). A total of 116 patients (6.2%) had CAT total scores of at least 10 at 2 years after discharge. Patients who had been admitted to the intensive care unit had higher risks of persistent symptoms (odds ratio, 2.69; 95% CI, 1.02-7.06; P = .04) and CAT scores of 10 or higher (odds ratio, 2.83; 95% CI, 1.21-6.66; P = .02). Conclusions and Relevance: In this cohort study, 2 years after hospital discharge, COVID-19 survivors had a progressive decrease in their symptom burden, but those with severe disease during hospitalization, especially those who required intensive care unit admission, had higher risks of persistent symptoms. These results are related to the original strain of the virus, and their relevance to infections with the Omicron variant is not known.

Not Only High Number and Specific Comorbidities but Also Age Are Closely Related to Progression and Poor Prognosis in Patients With COVID-19.

Background: Some patients with comorbidities and rapid disease progression have a poor prognosis. Aim: We aimed to investigate the characteristics of comorbidities and their relationship with disease progression and outcomes of COVID-19 patients. Methods: A total of 718 COVID-19 patients were divided into five clinical type groups and eight age-interval groups. The characteristics of comorbidities were compared between the different clinical type groups and between the different age-interval groups, and their relationships with disease progression and outcomes of COVID-19 patients were assessed. Results: Approximately 91.23% (655/718) of COVID-19 patients were younger than 60 years old. Approximately 64.76% (465/718) had one or more comorbidities, and common comorbidities included non-alcoholic fatty liver disease (NAFLD), hyperlipidaemia, hypertension, diabetes mellitus (DM), chronic hepatitis B (CHB), hyperuricaemia, and gout. COVID-19 patients with comorbidities were older, especially those with chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). Hypertension, DM, COPD, chronic kidney disease (CKD) and CVD were mainly found in severe COVID-19 patients. According to spearman correlation analysis the number of comorbidities was correlated positively with disease severity, the number of comorbidities and NAFLD were correlated positively with virus negative conversion time, hypertension, CKD and CVD were primarily associated with those who died, and the above-mentioned correlation existed independently of age. Risk factors included age, the number of comorbidities and hyperlipidaemia for disease severity, the number of comorbidities, hyperlipidaemia, NAFLD and COPD for the virus negative conversion time, and the number of comorbidities and CKD for prognosis. Number of comorbidities and age played a predictive role in disease progression and outcomes. Conclusion: Not only high number and specific comorbidities but also age are closely related to progression and poor prognosis in patients with COVID-19. These findings provide a reference for clinicians to focus on not only the number and specific comorbidities but also age in COVID-19 patients to predict disease progression and prognosis. Clinical Trial Registry: Chinese Clinical Trial Register ChiCTR2000034563.

Enhanced eosinophil-mediated inflammation associated with antibody and complement-dependent pneumonic insults in critical COVID-19.

Despite the worldwide effect of the coronavirus disease 2019 (COVID-19) pandemic, the underlying mechanisms of fatal viral pneumonia remain elusive. Here, we show that critical COVID-19 is associated with enhanced eosinophil-mediated inflammation when compared to non-critical cases. In addition, we confirm increased T helper (Th)2-biased adaptive immune responses, accompanying overt complement activation, in the critical group. Moreover, enhanced antibody responses and complement activation are associated with disease pathogenesis as evidenced by formation of immune complexes and membrane attack complexes in airways and vasculature of lung biopsies from six fatal cases, as well as by enhanced hallmark gene set signatures of Fcγ receptor (FcγR) signaling and complement activation in myeloid cells of respiratory specimens from critical COVID-19 patients. These results suggest that SARS-CoV-2 infection may drive specific innate immune responses, including eosinophil-mediated inflammation, and subsequent pulmonary pathogenesis via enhanced Th2-biased immune responses, which might be crucial drivers of critical disease in COVID-19 patients.

Potential transmission chains of variant B.1.1.7 and co-mutations of SARS-CoV-2.

The presence of SARS-CoV-2 mutants, including the emerging variant B.1.1.7, has raised great concerns in terms of pathogenesis, transmission, and immune escape. Characterizing SARS-CoV-2 mutations, evolution, and effects on infectivity and pathogenicity is crucial to the design of antibody therapies and surveillance strategies. Here, we analyzed 454,443 SARS-CoV-2 spike genes/proteins and 14,427 whole-genome sequences. We demonstrated that the early variant B.1.1.7 may not have evolved spontaneously in the United Kingdom or within human populations. Our extensive analyses suggested that Canidae, Mustelidae or Felidae, especially the Canidae family (for example, dog) could be a possible host of the direct progenitor of variant B.1.1.7. An alternative hypothesis is that the variant was simply yet to be sampled. Notably, the SARS-CoV-2 whole-genome represents a large number of potential co-mutations. In addition, we used an experimental SARS-CoV-2 reporter replicon system to introduce the dominant co-mutations NSP12_c14408t, 5'UTR_c241t, and NSP3_c3037t into the viral genome, and to monitor the effect of the mutations on viral replication. Our experimental results demonstrated that the co-mutations significantly attenuated the viral replication. The study provides valuable clues for discovering the transmission chains of variant B.1.1.7 and understanding the evolutionary process of SARS-CoV-2.