Sequential Administration of SARS-CoV-2 Strains-Based Vaccines Effectively Induces Potent Immune Responses against Previously Unexposed Omicron Strain.

In the past few years, the continuous pandemic of COVID-19 caused by SARS-CoV-2 has placed a huge burden on public health. In order to effectively deal with the emergence of new SARS-CoV-2 variants, it becomes meaningful to further enhance the immune responses of individuals who have completed the first-generation vaccination. To understand whether sequential administration using different variant sequence-based inactivated vaccines could induce better immunity against the forthcoming variants, we tried five inactivated vaccine combinations in a mouse model and compared their immune responses. Our results showed that the sequential strategies have a significant advantage over homologous immunization by inducing robust antigen-specific T cell immune responses in the early stages of immunization. Furthermore, the three-dose vaccination strategies in our research elicited better neutralizing antibody responses against the BA.2 Omicron strain. These data provide scientific clues for finding the optimal strategy within the existing vaccine platform in generating cross-immunity against multiple variants including previously unexposed strains.

Humoral immune response to omicron infection in long-term Wuhan-Hu-1-imprinted population (preprint)

Recent WHO vaccination guidance no longer recommends COVID-19 vaccination beyond the first booster in low risk population, citing high population-level hybrid immunity due to widespread omicron infections.1 Although SARS-CoV-2 infection confers durable protection against reinfection,2-4 it may also produce immune imprinting, which skews subsequent immune response to variant antigens toward the first-exposed antigen based on the antigenic distance.5,6 China has the earliest and exclusively Wuhan-Hu-1(WH1)-imprinted population before the 2022 nation-wide omicron outbreak,7 which offers a unique opportunity to study long-term immune imprinting between most antigenically distant strains. Here, we assessed pseudovirus neutralization activity and anti-WH1 receptor binding domain (RBD) antibodies in 4 Chinese cohorts with hybrid or vaccine-only imprinting, or naïve to SARS-CoV-2 prior to omicron BF.7 infection. Both hybrid and vaccine-only imprinting augmented post-infection serum neutralization of WH1 and omicron sub-variants BF.7/BQ.1.1/XBB.1.5 comparing to naïve background. Feedback from pre-existing high-affinity antibodies limited the magnitude of humoral immune response to omicron infection without compromising protection, while antigenic seniority of pre-existing cross-reactive B cells only slightly reduces forward neutralization breadth in hybrid- and RBD vaccine-imprinted participants. Our results support the effectiveness of hybrid immunity against omicron reinfection in long-term imprinted population and provide immunological basis for similar epidemiological findings.8-10

SARS-CoV-2 ORF3a sensitizes cells to ferroptosis via Keap1-NRF2 axis.

Viral infection-induced cell death has long been considered as a double-edged sword in the inhibition or exacerbation of viral infections. Patients with severe Coronavirus Disease 2019 (COVID-19) are characterized by multiple organ dysfunction syndrome and cytokine storm, which may result from SARS-CoV-2-induced cell death. Previous studies have observed enhanced ROS level and signs of ferroptosis in SARS-CoV-2 infected cells or specimens of patients with COVID-19, but the exact mechanism is not clear yet. Here, we find SARS-CoV-2 ORF3a sensitizes cells to ferroptosis via Keap1-NRF2 axis. SARS-CoV-2 ORF3a promotes the degradation of NRF2 through recruiting Keap1, thereby attenuating cellular resistance to oxidative stress and facilitated cells to ferroptotic cell death. Our study uncovers that SARS-CoV-2 ORF3a functions as a positive regulator of ferroptosis, which might explain SARS-CoV-2-induced damage in multiple organs in COVID-19 patients and imply the potential of ferroptosis inhibition in COVID-19 treatment.

Does increasing public expenditure on sports promote regional sustainable development: Evidence from China

In the post-COVID era, how to improve the level of regional sustainable development has attracted much attention. And the vigorous development of the sports economy may be closely related to the regional sustainable development. This paper explores the impact and mechanism analysis of government sports public expenditure on regional sustainable development from the perspective of sports economic development. The study found that China's sustainable development presents obvious ladder-like characteristics and highlights the regional imbalance and inadequacy of regional green and coordinated development. And the government's increase in public expenditure on sports can significantly promote regional sustainable development and improve the level of regional green and coordinated development. With the continuous improvement of the regional economic development, the effect of sports public expenditure continues to increase. It can be seen from this that implementing the strategy of strengthening the country through sports under the government's guidance is an essential guarantee for the public health and quality of life and the sustainable development of the economy and society. Additionally, the development level of market finance is also an important driving factor for the government's public expenditure on sports to improve the level of sustainable development in the region. From the mechanism analysis, the government activates the local residents' consumption level by increasing the public expenditure on sports, thus promoting regional sustainable development.

A soluble DR5-Fc chimeric protein attenuates inflammatory responses induced by coronavirus MHV-A59 and SARS-CoV-2.

Mortality in coronavirus disease 2019 (COVID-19) patients has been linked to the presence of a "cytokine storm" induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which involves elevated levels of circulating cytokines and immune-cell hyperactivation. Targeting cytokines during the management of COVID-19 patients has the potential to improve survival rates and reduce mortality. Although cytokine blockers and immune-host modulators are currently being tested in severely ill COVID-19 patients to cope with the overwhelming systemic inflammation, there is not too many successful cases, thus finding new cytokine blockers to attenuate the cytokine storm syndrome is meaningful. In this paper, we significantly attenuated the inflammatory responses induced by mouse hepatitis viruses A59 and SARS-CoV-2 through a soluble DR5-Fc (sDR5-Fc) chimeric protein that blocked the TNF-related apoptosis-inducing ligand-death receptor 5 (TRAIL-DR5) interaction. Our findings indicates that blocking the TRAIL-DR5 pathway through the sDR5-Fc chimeric protein is a promising strategy to treat COVID-19 severe patients requiring intensive care unit  admission or with chronic metabolic diseases.

Comparison of model-specific histopathology in mouse models of COVID-19.

A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified as the causative agent of the current coronavirus disease 2019 pandemic. Development of animal models that parallel the clinical and pathologic features of disease are highly essential to understanding the pathogenesis of SARS-CoV-2 infection and the development of therapeutics and prophylactics. Several mouse models that express the human angiotensin converting enzyme 2 (hACE2) have been created, including transgenic and knock-in strains, and viral vector-mediated delivery of hACE2. However, the comparative pathology of these mouse models infected with SARS-CoV-2 are unknown. Here, we perform systematic comparisons of the mouse models including K18-hACE2 mice, KI-hACE2 mice, Ad5-hACE2 mice and CAG-hACE2 mice, which revealed differences in the distribution of lesions and the characteristics of pneumonia induced. Based on these observations, the hACE2 mouse models meet different needs of SARS-CoV-2 researches. The similarities or differences among the model-specific pathologies may help in better understanding the pathogenic process of SARS-CoV-2 infection and aiding in the development of effective medications and prophylactic treatments for SARS-CoV-2.

A comprehensive evolutionary and epidemiological characterization of insertion and deletion mutations in SARS-CoV-2 genomes.

SARS-CoV-2, which causes the current pandemic of respiratory illness, is evolving continuously and generating new variants. Nevertheless, most of the sequence analyses thus far focused on nucleotide substitutions despite the fact that insertions and deletions (indels) are equally important in the evolution of SARS-CoV-2. In this study, we analyzed 1,099,664 high-quality sequences of SARS-CoV-2 genomes to re-construct the evolutionary and epidemiological histories of indels. Our analysis revealed 289 circulating indel types (237 deletion and 52 insertion types, each represented by more than ten genomic sequences), among which eighteen were recurrent indel types, each represented by more than 500 genome sequences. Although indels were identified across the entire genome, most of them were identified in nsp6, S, ORF8, and N genes, among which ORF8 indel types had the highest frequencies of frameshift. Geographical and temporal analyses of these variants revealed a few alterations of dominant indel types, each accompanied by geographic expansion to different countries and continents, which resulted in the fixation of several types of indels in the field, including the current variants of concern. Evolutionary and structural analyses revealed that indels involving S N-terminal domain regions were linked to the 3/4 variants of concern, resulting in significantly altered S protein that might contribute to the selective advantage of the corresponding variant. In sum, our study highlights the important role of insertions and deletions in the evolution and spread of SARS-CoV-2.

The Impact of Accumulated Mutations in SARS-CoV-2 Variants on the qPCR Detection Efficiency.

SARS-CoV-2 is evolving with mutations throughout the genome all the time and a number of major variants emerged, including several variants of concern (VOC), such as Delta and Omicron variants. In this study, we demonstrated that mutations in the regions corresponding to the sequences of the probes and 3'-end of primers have a significant impact on qPCR detection efficiency. We also found that the G28916T mutation of the N gene accounts for 78.78% sequenced genomes of Delta variant. It was found that detection sensitivity of G28916T mutant was 2.35 and 1.74 times less than that of the wt sequence and detection limit was reduced from 1 copy/µl to 10 copies/µl for the commercially available CP3 and CP4 primer/probe sets. These results indicate that the detection probes and primers should be optimized to keep maximal detection efficiency in response to the emergence of new variants.

A comprehensive evolutionary and epidemiological characterization of insertion and deletion mutations in SARS-CoV-2 genomes

SARS-CoV-2, which causes the current pandemic of respiratory illness, is evolving continuously and generating new variants. Nevertheless, most of the sequence analyses thus far focused on nucleotide substitutions despite the fact that insertions and deletions (indels) are equally important in the evolution of SARS-CoV-2. In this study, we analyzed 1,099,664 high-quality sequences of SARS-CoV-2 genomes to re-construct the evolutionary and epidemiological histories of indels. Our analysis revealed 289 circulating indel types (237 deletion and 52 insertion types, each represented by more than ten genomic sequences), among which eighteen were recurrent indel types, each represented by more than 500 genome sequences. Although indels were identified across the entire genome, most of them were identified in nsp6, S, ORF8, and N genes, among which ORF8 indel types had the highest frequencies of frameshift. Geographical and temporal analyses of these variants revealed a few alterations of dominant indel types, each accompanied by geographic expansion to different countries and continents, which resulted in the fixation of several types of indels in the field, including the current variants of concern. Evolutionary and structural analyses revealed that indels involving S N-terminal domain regions were linked to the 3/4 variants of concern, resulting in significantly altered S protein that might contribute to the selective advantage of the corresponding variant. In sum, our study highlights the important role of insertions and deletions in the evolution and spread of SARS-CoV-2.

The Effect of Noninvasive Ventilation Support on COVID-19 Patients and Risk Factors for Invasive Ventilation - A Retrospective and Multicenter Study.

BACKGROUND: Oxygen therapy (OT) is the most widely used supportive regime in patients with hypoxemic acute respiratory failure (ARF) due to severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. The aim of this study was to identify the effect of noninvasive ventilation support on coronavirus disease 2019 (COVID-19) patients and risk factors for invasive mechanical ventilation (IMV). METHODS: We retrospectively analyzed confirmed COVID-19 subjects from nine hospitals outside Wuhan. All hospitalized patients who tested positive for COVID-19 by real-time polymerase chain reaction between January 1st and March 31st, 2020, were recruited. The patients were divided into four groups based on the most advanced OT regime, including no OT, nasal oxygen therapy, high-flow nasal oxygen therapy (HFNOT) or noninvasive ventilation (NIV), and IMV. Multiple logistic regression models were performed to determine risk factors for IMV. RESULTS: Of the 683 recruited subjects, 315 (46.1%) subjects did not need OT, 300 (43.9%) received nasal oxygen therapy, 51 (7.5%) received HFNOT or NIV, while 17 (2.5%) subjects had to be intubated. The lactate in the OT group was higher than in the no OT group (2.7 vs 1.6, P = 0.02). In addition, HFNOT or NIV patients had a higher respiratory rate, but a lower PaO2 (P < 0.001). HFNOT and NIV had an obvious beneficial effect on ARF with 75% of COVID-19 patients recovering from respiratory failure. Patients with IMV were older (P < 0.001), had a higher rate of hypertension (P < 0.001) and more secondary bacterial infections (P < 0.001) compared to those without intubation. The multivariate model showed that secondary bacterial infection (OR = 6.87, P = 0.009) was independently associated with IMV failure among COVID-19 patients. CONCLUSION: We identified that HFNOT and NIV had an obvious beneficial effect on ARF among COVID-19 patients. We also demonstrated that secondary bacterial infection was an independent risk factor for NIV failure in patients infected by SARS-COV2.

Persistence of Antibody and Cellular Immune Responses in Coronavirus Disease 2019 Patients Over Nine Months After Infection.

BACKGROUND: The duration of humoral and T and B cell response after the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear. METHODS: We performed a cross-sectional study to assess the virus-specific antibody and memory T and B cell responses in coronavirus disease 2019 (COVID-19) patients up to 343 days after infection. Neutralizing antibodies and antibodies against the receptor-binding domain, spike, and nucleoprotein of SARS-CoV-2 were measured. Virus-specific memory T and B cell responses were analyzed. RESULTS: We enrolled 59 patients with COVID-19, including 38 moderate, 16 mild, and 5 asymptomatic patients; 31 (52.5%) were men and 28 (47.5%) were women. The median age was 41 years (interquartile range, 30-55). The median day from symptom onset to enrollment was 317 days (range 257 to 343 days). We found that approximately 90% of patients still have detectable immunoglobulin (Ig)G antibodies against spike and nucleocapsid proteins and neutralizing antibodies against pseudovirus, whereas ~60% of patients had detectable IgG antibodies against receptor-binding domain and surrogate virus-neutralizing antibodies. The SARS-CoV-2-specific IgG+ memory B cell and interferon-γ-secreting T cell responses were detectable in more than 70% of patients. CONCLUSIONS: Severe acute respiratory syndrome coronavirus 2-specific immune memory response persists in most patients approximately 1 year after infection, which provides a promising sign for prevention from reinfection and vaccination strategy.

COVID-19 and gastroenteric manifestations.

Coronavirus disease 2019 (COVID-19), caused by the infection of a novel coronavirus [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)], has become a pandemic. The infection has resulted in about one hundred million COVID-19 cases and millions of deaths. Although SARS-CoV-2 mainly spreads through the air and impairs the function of the respiratory system, it also attacks the gastrointestinal epithelial cells through the same receptor, angiotensin converting enzyme 2 receptor, which results in gastroenteric symptoms and potential fecal-oral transmission. Besides the infection of SARS-CoV-2, the treatments of COVID-19 also contribute to the gastroenteric manifestations due to the adverse drug reactions of anti-COVID-19 drugs. In this review, we update the clinical features, basic studies, and clinical practices of COVID-19-associated gastroenteric manifestations.

Clinical Findings in Diabetes Mellitus Patients with COVID-19.

BACKGROUNDS: Diabetes mellitus (DM) is one of the most common comorbidities in patients with coronavirus disease (COVID-19). We aim to summarize the clinical features of DM patients with COVID-19 and find out potential factors associated with severe disease. METHODS: In this retrospective, single-center study, the medical records of patients with COVID-19 in Changsha, Hunan, China, from January 21, 2020, to February 19, 2020, were reviewed. Epidemiological information, clinical features, and outcomes were compared between DM patients admitted to the intensive care unit (ICU) or not. RESULTS: A total of 241 patients confirmed with COVID-19 were enrolled, including 19 DM patients. There were more patients in DM group admitted to the ICU than non-DM group (36.8% vs. 15.8%, P = 0.045). Compared with non-DM group in the ICU, there were more female patients from DM group in the ICU (85.7% vs. 31.4%, P = 0.024). On admission, the mean level of glycated hemoglobin A1c (HbA1c) was higher in the ICU DM patients than that in the non-ICU DM patients (8.5% vs. 7.1%). There were more DM patients with proteinuria in the ICU group than the non-ICU group (57.1% vs. 33.3%). Twelve DM patients (63.2%) changed diabetic therapy during hospitalization, and all DM patients admitted to the ICU used insulin. As of March 14, all 19 DM patients have been discharged, and no death occurred. CONCLUSIONS: DM patients with COVID-19 are vulnerable to severe disease, especially for female patients. High levels of HbA1c and proteinuria could be potential risk factors for severe COVID-19 in DM patients. In addition to timely systemic therapy, the control of blood glucose and proper diabetic therapy is essential to improve the prognosis of severe DM patients with COVID-19.

Combined Interventions for Severe Novel Coronavirus Disease (COVID-19): Experience from 350 Patients.

PURPOSE: To summarize the clinical features and effective therapy of severe COVID-19 patients. PATIENTS AND METHODS: In this retrospective, multicenter study, the medical records of COVID-19 patients in Hunan, from January 21, 2020 to February 19, 2020 were reviewed. RESULTS: Of the 350 COVID-19 patients, 13.7% were severe cases. On admission, compared with non-severe patients, more severe patients had a neutrophil/lymphocyte ratio > 3 (58.3% vs 33.8%, P=0.001), D-dimer > 1 mg/L (41.7% vs 13.6%, P<0.0001), higher level of CRP (39.1 mg/L, IQR18.1-75.9 vs 13.4 mg/L, IQR5.0-32.8, P<0.0001), and multiple pneumonia on CT (77.1% vs 18.2%, P<0.0001). All severe patients received oxygen support. 95.8% of them received antivirals, and the most frequent therapy was lopinavir and ritonavir plus human interferon-α2b. Moxifloxacin was used in 70.8% severe patients. The total dosage of methylprednisolone sodium succinate was 640 mg (IQR 360-960) in severe patients, and the duration of use was 8.5 days (IQR 6.8-11.3). The total dosage of immunoglobulin was 80 g (IQR, 60-140) in severe patients, and the duration was 8.0 days (IQR, 6.0-11.5). As of March 15, 2020, 95.8% of the severe patients had been discharged and only two deaths occurred. CONCLUSION: The rate of severe cases and mortality of COVID-19 in Hunan are lower than those in Wuhan. In addition to antivirals and oxygen support, timely interventions including corticosteroids, immunoglobulin, and antibiotics, contribute to improving the prognosis of severe COVID-19 patients.

De novo design of potent and resilient hACE2 decoys to neutralize SARS-CoV-2.

We developed a de novo protein design strategy to swiftly engineer decoys for neutralizing pathogens that exploit extracellular host proteins to infect the cell. Our pipeline allowed the design, validation, and optimization of de novo human angiotensin-converting enzyme 2 (hACE2) decoys to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The best monovalent decoy, CTC-445.2, bound with low nanomolar affinity and high specificity to the receptor-binding domain (RBD) of the spike protein. Cryo-electron microscopy (cryo-EM) showed that the design is accurate and can simultaneously bind to all three RBDs of a single spike protein. Because the decoy replicates the spike protein target interface in hACE2, it is intrinsically resilient to viral mutational escape. A bivalent decoy, CTC-445.2d, showed ~10-fold improvement in binding. CTC-445.2d potently neutralized SARS-CoV-2 infection of cells in vitro, and a single intranasal prophylactic dose of decoy protected Syrian hamsters from a subsequent lethal SARS-CoV-2 challenge.

Characteristics of and Public Health Responses to the Coronavirus Disease 2019 Outbreak in China.

In December 2019, cases of unidentified pneumonia with a history of exposure in the Huanan Seafood Market were reported in Wuhan, Hubei Province. A novel coronavirus, SARS-CoV-2, was identified to be accountable for this disease. Human-to-human transmission is confirmed, and this disease (named COVID-19 by World Health Organization (WHO)) spread rapidly around the country and the world. As of 18 February 2020, the number of confirmed cases had reached 75,199 with 2009 fatalities. The COVID-19 resulted in a much lower case-fatality rate (about 2.67%) among the confirmed cases, compared with Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). Among the symptom composition of the 45 fatality cases collected from the released official reports, the top four are fever, cough, short of breath, and chest tightness/pain. The major comorbidities of the fatality cases include hypertension, diabetes, coronary heart disease, cerebral infarction, and chronic bronchitis. The source of the virus and the pathogenesis of this disease are still unconfirmed. No specific therapeutic drug has been found. The Chinese Government has initiated a level-1 public health response to prevent the spread of the disease. Meanwhile, it is also crucial to speed up the development of vaccines and drugs for treatment, which will enable us to defeat COVID-19 as soon as possible.

Pathogenic mechanism of liver injury caused by coronavirus disease 2019 and protective strategies for patients with viral hepatitis cirrhosis

Coronavirus disease 2019 (COVID-19) has spread to many countries in the world, and some patients show liver injury during the epidemic of COVID-19. In order to improve the awareness of COVID-19 among patients with viral hepatitis cirrhosis and strengthen patients' self-protection and disease management, this article discusses the pathogenic mechanism of liver injury caused by COVID-19 and reasonable epidemic prevention, standardized medical treatment, and scientific medication for such patients and gives related recommendations, so as to ensure the routine management of viral hepatitis and reduce the risk of infection in such population.