Potent immunogenicity and broad-spectrum protection potential of microneedle array patch-based COVID-19 DNA vaccine candidates encoding dimeric RBD chimera of SARS-CoV and SARS-CoV-2 variants.

Breakthrough infections by SARS-CoV-2 variants pose a global challenge to COVID-19 pandemic control, and the development of more effective vaccines of broad-spectrum protection is needed. In this study, we constructed pVAX1-based plasmids encoding receptor-binding domain (RBD) chimera of SARS-CoV-1 and SARS-CoV-2 variants, including pAD1002 (encoding RBDSARS/BA1), pAD1003 (encoding RBDSARS/Beta) and pAD131 (encoding RBDBA1/Beta). Plasmids pAD1002 and pAD131 were far more immunogenic than pAD1003 in terms of eliciting RBD-specific IgG when intramuscularly administered without electroporation. Furthermore, dissolvable microneedle array patches (MAP) greatly enhanced the immunogenicity of these DNA constructs in mice and rabbits. MAP laden with pAD1002 (MAP-1002) significantly outperformed inactivated SARS-CoV-2 virus vaccine in inducing RBD-specific IFN-γ+ effector and memory T cells, and generated T lymphocytes of different homing patterns compared to that induced by electroporated DNA in mice. In consistence with the high titer neutralization results of MAP-1002 antisera against SARS-CoV-2 pseudoviruses, MAP-1002 protected human ACE2-transgenic mice from Omicron BA.1 challenge. Collectively, MAP-based DNA constructs encoding chimeric RBDs of SARS-CoV-1 and SARS-CoV-2 variants, as represented by MAP-1002, are potential COVID-19 vaccine candidates worthy further translational study.

A DNA Vaccine Encoding the Full-Length Spike Protein of Beta Variant (B.1.351) Elicited Broader Cross-Reactive Immune Responses against Other SARS-CoV-2 Variants.

The SARS-CoV-2 pandemic remains an ongoing threat to global health with emerging variants, especially the Omicron variant and its sub-lineages. Although large-scale vaccination worldwide has delivered outstanding achievements for COVID-19 prevention, a declining effectiveness to a different extent in emerging SARS-CoV-2 variants was observed in the vaccinated population. Vaccines eliciting broader spectrum neutralizing antibodies and cellular immune responses are urgently needed and important. To achieve this goal, rational vaccine design, including antigen modeling, screening and combination, vaccine pipelines, and delivery, are keys to developing a next-generation COVID-19 vaccine. In this study, we designed several DNA constructs based on codon-optimized spike coding regions of several SARS-CoV-2 variants and analyzed their cross-reactive antibodies, including neutralizing antibodies, and cellular immune responses against several VOCs in C57BL/6 mice. The results revealed that different SARS-CoV-2 VOCs induced different cross-reactivity; pBeta, a DNA vaccine encoding the spike protein of the Beta variant, elicited broader cross-reactive neutralizing antibodies against other variants including the Omicron variants BA.1 and BA.4/5. This result demonstrates that the spike antigen from the Beta variant potentially serves as one of the antigens for multivalent vaccine design and development against variants of SARS-CoV-2.

Human Activity Changes during COVID‐19 Lockdown in China—A View from Nighttime Light

Strict lockdowns were implemented in China to fight Coronavirus Disease 2019 (COVID‐19). We explored the nighttime light (NTL) of China’s four cities in five stages of COVID‐19 including case free period, newly appeared period, rising period, outbreak period, and stationary period. Using six categories of points of interest (POIs) data (“company”, “recreation”, “healthcare”, “residence”, “shopping”, and “traffic facility”) and random forest models, we found that dimming light of four cities is associated with the epidemic development and human activity changes. When confirmed cases appeared, healthcare associated NTL radiance increased rapidly in Wuhan and Guangzhou, but decreased in the fourth and fifth stages. Companies in all cities were resuscitated in the fifth stage, while companies in Guangzhou was resuscitated in the fourth stage. Shopping related NTL radiance in Wuhan increased quickly in the fifth stage which indicated some resuscitation. In addition, compared to gross domestic product (GDP), the trend in electric power consumption (EPC) was consistent with the trend in NTL radiance. The above findings contribute to the making of control policies for COVID‐19 as well as other infectious diseases. Key Points Dimming light during COVID‐19 lockdown observed by satellite coincides with the stage of epidemic development Changes in six categories of human activity can be considerably explained by nighttime light changes (around 52%) GDP (or electric power consumption) has a consistent trend with the nighttime light radiance

Identification of a promiscuous conserved CTL epitope within the SARS-CoV-2 spike protein.

ABSTRACTThe COVID-19 disease caused by infection with SARS-CoV-2 and its variants is devastating to the global public health and economy. To date, over a hundred COVID-19 vaccines are known to be under development, and the few that have been approved to fight the disease are using the spike protein as the primary target antigen. Although virus-neutralizing epitopes are mainly located within the RBD of the spike protein, the presence of T cell epitopes, particularly the CTL epitopes that are likely to be needed for killing infected cells, has received comparatively little attention. This study predicted several potential T cell epitopes with web-based analytic tools and narrowed them down from several potential MHC-I and MHC-II epitopes by ELIspot and cytolytic assays to a conserved MHC-I epitope. The epitope is highly conserved in current viral variants and compatible with a presentation by most HLA alleles worldwide. In conclusion, we identified a CTL epitope suitable for evaluating the CD8+ T cell-mediated cellular response and potentially for addition into future COVID-19 vaccine candidates to maximize CTL responses against SARS-CoV-2.

Eltrombopag is a potential target for drug intervention in SARS-CoV-2 spike protein.

The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a current global threat for which there is an urgent need to search for an effective therapy. The transmembrane spike (S) glycoprotein of SARS-CoV-2 directly binds to the host angiotensin-converting enzyme 2 (ACE2) and mediates viral entrance, which is therefore considered as a promising drug target. Considering that new drug development is a time-consuming process, drug repositioning may facilitate rapid drug discovery dealing with sudden infectious diseases. Here, we compared the differences between the virtual structural proteins of SARS-CoV-2 and SARS-CoV, and selected a pocket mainly localizing in the fusion cores of S2 domain for drug screening. A virtual drug design algorithm screened the Food and Drug Administration-approved drug library of 1234 compounds, and 13 top scored compounds were obtained through manual screening. Through in vitro molecular interaction experiments, eltrombopag was further verified to possess a high binding affinity to S protein plus human ACE2 and could potentially affect the stability of the ACE2-S protein complex. Hence, it is worth further exploring eltrombopag as a potential drug for the treatment of SARS-CoV-2 infection.

Epidemiological and clinical characteristics of fifty-six cases of COVID-19 in Liaoning Province, China.

BACKGROUND: Pneumonia of uncertain cause has been reported in Wuhan, China since the beginning of early December 2019. In early January 2020, a novel strain of ß-coronavirus was identified by the Chinese Center for Disease Control and Prevention from the pharyngeal swab specimens of patients, which was recently named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There is evidence of human-to-human transmission and familial cluster outbreak of SARS-CoV-2 infection. The World Health Organization(WHO) recently declared the SARS-CoV-2 epidemic a global health emergency. As of February 17, 2020, 71329 laboratory-confirmed cases (in 25 countries, including the United States and Germany) have been reported globally. Other than its rapid transmission, the epidemiological and clinical characteristics of coronavirus disease 2019 (COVID-19) remain unclear. In December 2019, coronavirus disease (named COVID-19 by the WHO) associated with the SARS-CoV-2 emerged in Wuhan, China and spread quickly across the country. AIM: To analyze the epidemiological and clinical characteristics of confirmed cases of this disease in Liaoning province, a Chinese region about 1800 km north of Wuhan. METHODS: The clinical data of 56 laboratory-confirmed COVID-19 cases due to 2019-nCoV infection were analyzed. The cases originated from eight cities in Liaoning province. RESULTS: The median age of the patients was 45 years, and 57.1% of them were male. No patient had been in direct contact with wild animals. Among them, 23 patients (41.1%) had resided in or traveled to Wuhan, 27 cases (48.2%) had been in contact with confirmed COVID-19 patients, 5 cases (8.9%) had been in contact with confirmed patients with a contact history to COVID-19 patients, and 1 case (1.8%) had no apparent history of exposure. Fever (75.0%) and cough (60.7%) were the most common symptoms. The typical manifestations in lung computed tomography (CT) included ground-glass opacity and patchy shadows, with 67.8% of them being bilateral. Among the patients in the cohort, 78.6% showed reduction in their lymphocyte counts, 57.1% showed increases in their C-reactive protein levels, and 50.0% showed decreases in their blood albumin levels. Eleven patients (19.6%) were admitted to intensive care unit, 2 patients (3.5%) progressed to acute respiratory distress syndrome, 4 patients (7.1%) were equipped with non-invasive mechanical ventilation, and 1 patient (1.8) received extracorporeal membrane oxygenation support. There were 5 mild cases (5/56, 8.9%), 40 moderate cases (40/56, 71.4%), 10 severe cases (10/56, 17.9%), and 1 critical case (1/56, 1.8%). No deaths were reported. CONCLUSION: SARS-CoV-2 can be transmitted among humans. Most COVID-19 patients show symptoms of fever, cough, lymphocyte reduction, and typical lung CT manifestations. Most are moderate cases. The seriousness of the disease (as indicated by blood oxygen saturation, respiratory rate, oxygenation index, blood lymphocyte count, and lesions shown in lung CT) is related to history of living in or traveling to Wuhan, underlying diseases, admittance to intensive care unit, and mechanical ventilation.

Clinical characteristics and survival analysis in critical and non-critical patients with COVID-19 in Wuhan, China: a single-center retrospective case control study.

Since the outbreak of COVID-19 in China at the end of 2019, the world has experienced a large-scale epidemic caused by the SARS-CoV-2. The epidemiological and clinical course of COVID-19 patients has been reported, but there have been few analyses about the characteristics, predictive risk factors, and outcomes of critical patients. In this single-center retrospective case-control study, 90 adult inpatients hospitalized at Tongji Hospital (Wuhan, China) were included. Demographic, clinical, laboratory tests, and treatment data were obtained and compared between critical and non-critical patients. We found that compared with non-critical patients, the critical patients had higher SOFA score and qSOFA scores. Critical patients had lower lymphocyte and platelet count, elevated D-dimer, decreased fibrinogen, and elevated high-sensitivity C-reactive protein (hsCRP), and interleukin-6(IL-6). More critical patients received treatment including antibiotics, anticoagulation, corticosteroid, and oxygen therapy than non-critical ones. Multivariable regression showed higher qSOFA score and elevation of IL-6 were related to critical patients. Antibiotic usage and anticoagulation were associated with decreased in-hospital mortality. And critical grouping contributed greatly to in-hospital death. Critical COVID-19 patients have a more severe clinical course. qSOFA score and elevation of IL-6 are risk factors for critical condition. Non-critical grouping, positive antibiotic application, and anticoagulation may be beneficial for patient survival.

Enlightenments of Asymptomatic Cases of SARS-CoV-2 Infection.

This article reports two asymptomatic cases of SARS-CoV-2 infection. Both cases came from Hubei Province. One was a 63-year-old male and the other was a 29-year-old female. Both were diagnosed with SARS-CoV-2 infection during the screening of high-risk personnel from the affected areas. During the 14-day isolation medical observation, they had no symptoms, their blood lymphocyte count and lung CT examinations were normal. An asymptomatic infection had been diagnosed, however, it was not "asymptomatic infection" state in incubation period. Due to the timely and effective isolation measures taken for the two cases, no other persons have been infected by them. Therefore, effective control of the source of infection, cutting off the route of transmission, and protecting vulnerable populations are currently effective measures to prevent the spread of coronavirus infected disease.