The latest research progress of novel coronavirus "Omicron sub-variant BA.5"

Since the outbreak of COVID-19, severe acute respiratory syndrome coronavirus 2 genome is still mutating, forming a variety of variants with strong transmission capacity, causing the spread of the epidemic worldwide, posing a serious threat to people's physical and mental health, and posing a major challenge to global public health. Omicron remains the main variant in several outbreaks worldwide, accounting for about 99% of the global genetic sequence. Recently, the World Health Organization announced that the subvariant of Omicron BA.5 has been found in more than 100 countries and regions around the world, causing the global epidemic rebound. However, there are few studies on the subvariant BA.5. This article reviews the latest research progress in epidemiology, infectivity, pathogenicity, vaccine and monoclonal antibody protection against Omicron subvariant BA.5, in order to provide reference for scientific prevention and control of Omicron subvariant BA.5.

The latest research progress in asymptomatic and pre-symptomatic patients with COVID-19

The asymptomatic and pre-symptomatic infections of coronavirus disease 2019 (COVID-19) has no perceptible clinical symptoms and signs, and it is not easy to be detected. The transmission of the virus carried by asymptomatic and pre-symptomatic patients is insidious, which brings great challenges to the control of the epidemic. Due to the length of the incubation period, some studies have failed to distinguish between asymptomatic and pre-symptomatic infections, resulting in a higher proportion of asymptomatic infections. This article reviews the latest research progress of characteristics, transmission, detection and control of asymptomatic and pre-symptomatic infection.

Research progress on detection methods of the asymptomatic COVID-19 infected persons

The global pandemic of COVID-19 has brought great harm and challenges to many countries and regions around the world. The majority of COVID-19 patients have typical clinical manifestations, but the number of asymptomatic infections is increasing as COVID-19 research continues and SARS-CoV-2 testing improves. Many asymptomatic COVID-19 patients with no obvious clinical symptoms are able to transmit the virus to others due to the presence of SARS-CoV-2 in their bodies, thus greatly accelerating the worldwide pandemic and posing great difficulty and threat to global epidemic prevention and control. Therefore, early detection and identification of asymptomatic infected persons through various testing methods are effective measures to control the COVID-19 pandemic. This article will provide a brief review of the available methods and techniques for detecting asymptomatic COVID-19 patients.

Research progress on the effect of COVID-19 on gastrointestinal tract

The outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) in 2019 threatens global public health. In the early stage, respiratory symptoms are the most common in patients with new coronal pneumonia, but with the spread of the disease around the world, gastrointestinal symptoms such as diarrhea, nausea and vomiting have attracted more and more attention. And some patients take diarrhea as the first symptom, which is easy to cause missed diagnosis. This paper expounds the close relationship between COVID-19 and gastrointestinal tract, and reviews the research progress of COVID-19's effect on gastrointestinal tract.

Induction of Broadly Cross-Reactive Antibody Responses to SARS-CoV-2 Variants by S1 Nanoparticle Vaccines.

Despite the rapid deployment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, the emergence of SARS-CoV-2 variants and reports of their immune evasion characteristics have led to an urgent need for novel vaccines that confer potent cross-protective immunity. In this study, we constructed three different SARS-CoV-2 spike S1-conjugated nanoparticle vaccine candidates that exhibited high structural homogeneity and stability. Notably, these vaccines elicited up to 50-times-higher neutralizing antibody titers than the S1 monomer in mice. Crucially, it was found that the S1-conjugated nanoparticle vaccine could elicit comparable levels of neutralizing antibodies against wild-type or emerging variant SARS-CoV-2, with cross-reactivity to SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), the effect of which could be further enhanced using our designed nanoparticles. Our results indicate that the S1-conjugated nanoparticles are promising vaccine candidates with the potential to elicit potent and cross-reactive immunity against not only wild-type SARS-CoV-2, but also its variants of concern, variants of interest, and even other pathogenic betacoronaviruses. IMPORTANCE The emergence of SARS-CoV-2 variants led to an urgent demand for a broadly effective vaccine against the threat of variant infection. The spike protein S1-based nanoparticle designed in our study could elicit a comprehensive humoral response toward different SARS-CoV-2 variants of concern and variants of interest and will be helpful to combat COVID-19 globally.

Traceable surveillance and genetic diversity analysis of coronaviruses in poultry from China in 2019.

Coronavirus disease 2019 (COVID-19), caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in Wuhan, China, and rapidly spread throughout the world. This newly emerging pathogen is highly transmittable and can cause fatal disease. More than 35 million cases have been confirmed, with a fatality rate of about 2.9% to October 9, 2020. However, the original and intermediate hosts of SARS-CoV-2 remain unknown. Here, 3160 poultry samples collected from 14 provinces of China between September and December 2019 were tested for SARS-CoV-2 infection. All the samples were SARS-CoV-2 negative, but 593 avian coronaviruses were detected, including 485 avian infectious bronchitis viruses, 72 duck coronaviruses, and 36 pigeon coronaviruses, with positivity rates of 15.35%, 2.28%, and 1.14%, respectively. Our surveillance demonstrates the diversity of avian coronaviruses in China, with higher prevalence rates in some regions. Furthermore, the possibility that SARS-CoV-2 originated from a known avian-origin coronavirus can be preliminarily ruled out. More surveillance of and research into avian coronaviruses are required to better understand the diversity, distribution, cross-species transmission, and clinical significance of these viruses.

Rapid Development of SARS-CoV-2 Spike Protein Receptor-Binding Domain Self-Assembled Nanoparticle Vaccine Candidates.

The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion. Thus, the RBD is an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticle vaccine candidates, namely, RBD-Ferritin (24-mer), RBD-mi3 (60-mer), and RBD-I53-50 (120-mer), via covalent conjugation using the SpyTag-SpyCatcher system. When mice were immunized with the RBD-conjugated nanoparticles (NPs) in conjunction with the AddaVax or Sigma Adjuvant System, the resulting antisera exhibited 8- to 120-fold greater neutralizing activity against both a pseudovirus and the authentic virus than those of mice immunized with monomeric RBD. Most importantly, sera from mice immunized with RBD-conjugated NPs more efficiently blocked the binding of RBD to ACE2 in vitro, further corroborating the promising immunization effect. Additionally, the vaccine has distinct advantages in terms of a relatively simple scale-up and flexible assembly. These results illustrate that the SARS-CoV-2 RBD-conjugated nanoparticles developed in this study are a competitive vaccine candidate and that the carrier nanoparticles could be adopted as a universal platform for a future vaccine development.

New HIV diagnoses in patients with COVID-19: two case reports and a brief literature review.

BACKGROUND: COVID-19 is novel infectious disease with an evolving understanding of its epidemiology and clinical manifestations. Severe cases developed life-threatening complications, such as respiratory failure, shock, and multiple organs dysfunction. Immunocompromised patients often present atypical presentations of viral infected diseases. CASE PRESENTATION: We report newly diagnosed HIV infections in two patients with COVID-19 in China. In our two cases, both patients with elevated IL-6 received Tocilizumab treatment, but did not present obvious therapeutic effect. CONCLUSIONS: These cases highlight possible co-detection of known immunocompromised diseases such as HIV. The two cases we reported stressed the risk of misdiagnosis, especially during the pandemic of an infectious disease and the importance of extended testing even if in immune-compromised condition the immune state may be ignored.

The effects of chloroquine and hydroxychloroquine on ACE2 related coronavirus pathology and the cardiovascular system: An evidence based review

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a serious threat to global public health and there is currently no effective antiviral therapy. It has been suggested that Chloroquine (CQ) and hydroxychloroquine (HCQ), which were primarily employed as prophylaxis and treatment for malaria, could be used to treat COVID-19. CQ and HCQ may be potential inhibitors of SARS-CoV-2 entry into host cells, which is mediated via the angiotensin-converting enzyme 2 (ACE2), and may also inhibit subsequent intracellular processes which lead to COVID-19, including damage to the cardiovascular system. However, paradoxically, CQ and HCQ have also been reported to cause damage to the cardiovascular system. In this review, we provide a critical examination of the published evidence. CQ and HCQ could potentially be useful drugs in the treatment of COVID-19 and other ACE2 involved virus infections, but the antiviral effects of CQ and HCQ need to be tested in more well-designed clinical randomized studies and their actions on the cardiovascular system need to be further elucidated. However, even if it were to turn out that CQ and HCQ are not useful drugs in practice, further studies of their mechanism of action could be helpful in improving our understanding of COVID-19 pathology.

Surveillance and taxonomic analysis of the coronavirus dominant in pigeons in China.

Coronaviruses (CoVs) are found in humans and a wide variety of wild and domestic animals, and of substantial impact on human and animal health. In poultry, the genetic diversity, evolution, distribution and taxonomy of CoVs dominant in birds other than chickens remain enigmatic. In our previous study, we proposed that the CoVs dominant (i.e. mainly circulating) in ducks (DdCoVs) should represent a novel species, which was different from the one represented by the CoVs dominant in chickens (CdCoVs). In this study, we conducted a large-scale surveillance of CoVs in chickens, ducks, geese, pigeons and other birds (quails, sparrows and partridges) using a conserved RT-PCR assay. The surveillance demonstrated that CdCoVs, DdCoVs and the CoVs dominant in pigeons (PdCoVs) belong to different lineages, and they are all prevalent in live poultry markets and the backyard flocks in some regions of China. We further sequenced seven Coronaviridae-wide conserved domains in their replicase polyprotein pp1ab of seven PdCoVs and found that the genetic distances in these domains between PdCoVs and DdCoVs or CdCoVs are large enough to separate PdCoVs into a novel species, which were different from the ones represented by DdCoVs or CdCoVs within the genus Gammacoronavirus, per the species demarcation criterion of International Committee on Taxonomy of Viruses. This report shed novel insight into the genetic diversity, distribution, evolution and taxonomy of avian CoVs.