Antibody-dependent enhancement and SARS-CoV-2 vaccines and therapies

COVID-19 Pandemic: Epidemiology, Etiology, Conventional and Non-Conventional Therapies

Coronavirus disease 2019 (COVID-19), which reported in an outbreak in 2019 in Wuhan, Hubei province, China, is caused by the SARS-CoV-2 virus. The virus belongs to the beta-coronavirus class, along with the Middle East Respiratory Syndrome coronavirus and Severe Acute Respiratory Syndrome coronavirus. Interestingly, the virus binds with angiotensin-converting enzyme-2 found in host cells, through the spike (S) protein that exists on its surface. This binding causes the entry of the virus into cells of the host organism. The actual mechanism used by the COVID-19 virus to induce disease is still speculative. A total of 44,322,504 cases, a 1,173,189 death toll and 32,486,703 recovery cases have been reported in 217 countries globally as of 28 October 2020. Symptoms from the infection of the virus include chest pain, fever, fatigue, nausea, and others. Acute respiratory stress syndrome, arrhythmia, and shock are some of the chronic manifestations recorded in severe COVID-19. Transmission is majorly by individual-to-individual through coughing, sneezing, etc. The lack of knowledge regarding the mechanism of and immune response to the virus has posed a challenge in the development of a novel drug and vaccine. Currently, treatment of the disease involves the use of anti-viral medications such as lopinavir, remdesivir, and other drugs. These drugs show some efficacy in the management of COVID-19. Studies are still on-going for the development of an ideal and novel drug for treatment. In terms of natural product intervention, Traditional Chinese Medicines (TCM) have been employed to alleviate the clinical manifestation and severity of the disease and have shown some efficacy. This review presents an updated detailed overview of COVID-19 and the virus, concerning its structure, epidemiology, symptoms and transmission, immune responses, and current interventions, and highlights the potential of TCM. It is anticipated that this review will further add to the understanding of COVID-19 and the virus, hence opening new research perspectives.

Profile of SARS-CoV-2

The recent emergence of a new coronavirus (severe acute respiratory syndrome coronavirus‑2, SARS-CoV-2) that is transmitted efficiently among humans and can result in serious disease and/or death has become a global threat to public health and economy. In this article, we describe some of the most important characteristics of this new virus (including gaps in our understanding) and provide a perspective of ongoing activities for developing virus-specific countermeasures, such as vaccines and antiviral drugs.

COVID-19 Vaccine Frontrunners and Their Nanotechnology Design

Humanity is experiencing a catastrophic pandemic. SARS-CoV-2 has spread globally to cause significant morbidity and mortality, and there still remain unknowns about the biology and pathology of the virus. Even with testing, tracing, and social distancing, many countries are struggling to contain SARS-CoV-2. COVID-19 will only be suppressible when herd immunity develops, either because of an effective vaccine or if the population has been infected and is resistant to reinfection. There is virtually no chance of a return to pre-COVID-19 societal behavior until there is an effective vaccine. Concerted efforts by physicians, academic laboratories, and companies around the world have improved detection and treatment and made promising early steps, developing many vaccine candidates at a pace that has been unmatched for prior diseases. As of August 11, 2020, 28 of these companies have advanced into clinical trials with Moderna, CanSino, the University of Oxford, BioNTech, Sinovac, Sinopharm, Anhui Zhifei Longcom, Inovio, Novavax, Vaxine, Zydus Cadila, Institute of Medical Biology, and the Gamaleya Research Institute having moved beyond their initial safety and immunogenicity studies. This review analyzes these frontrunners in the vaccine development space and delves into their posted results while highlighting the role of the nanotechnologies applied by all the vaccine developers.

Perspective: Reducing SARS-CoV2 Infectivity and Its Associated Immunopathology

COVID-19 has become difficult to contain in our interconnected world. In this article, we discuss some approaches that could reduce the consequences of COVID-19. We elaborate upon the utility of camelid single-domain antibodies (sdAbs), also referred to as nanobodies, which are naturally poised to neutralize viruses without enhancing its infectivity. Smaller sized sdAbs can be easily selected using microbes or the subcellular organelle display methods and can neutralize SARS-CoV2 infectivity. We also discuss issues related to their production using scalable platforms. The favorable outcome of the infection is evident in patients when the inflammatory response is adequately curtailed. Therefore, we discuss approaches to mitigate hyperinflammatory reactions initiated by SARS-CoV2 but orchestrated by immune mediators.

[Pathology and Immunology of COVID-19]

Since the first case of COVID-19 was reported from Wuhan, China in December 2019, SARS-CoV-2 has been spreading globally and has become major public health concern. At present, development of specific treatment for COVID-19 is in progress and several countermeasures have been subjected to clinical trials. However, efficacy of these countermeasures is limited. For development of effective medicines or vaccines against infectious diseases, it is mandatory to elucidate its etiology and pathogenesis by means of pathological analysis. Pathological studies revealed that the COVID-19 mainly affects respiratory tracts although other organs are also involved. In addition, immunological studies demonstrated that host immune response may exacerbates COVID-19 through systemic inflammation. In this review, we would like to overview pathology and immunology of COVID-19.