SARS-CoV-2 Biochemistry, Transmission, Clinical Manifestations, and Prevention

Abstract

The first human case of COVID-19, caused by the novel coronavirus, was reported by health officials in the city of Wuhan, China, in December of 2019. The virus was identified as a novel coronavirus in early January 2020, and its genetic sequence was shared publicly on January 11, 2020. The novel virus, previously called 2019-novel coronavirus (2019-nCoV), is currently designated as the severe respiratory syndrome coronavirus-2 (SARS-CoV-2). On January 23, Wuhan was locked down, and the World Health Organization (WHO) declared a “public health emergency of international concern.” The viral genome of SARS-CoV-2 is around 29.8 kilobase, containing six major open reading frames. The most common clinical symptoms were fever, cough, fatigue, shortness of breath, dyspnea, muscle ache, headache, chest pain, vomiting, sore throat, and sputum production. The main mode of transmission is through respiratory particles. The incubation period is 3 to 7 days. Both asymptomatic and symptomatic patients seem to be infectious. Spike (S) proteins of SARS-CoV-2 seem to have a 10- to 20-fold higher affinity to the human angiotensin enzyme 2 (ACE2) receptor than that of SARS-CoV. The high affinity of S protein to theACE2 receptor, and the additional advantages offered by the transfection facilitators Furin and Neutropilin-1, likely, contributes to the rapid spreading of this novel virus. Since these receptors are highly expressed on a variety of cells, including vascular endothelial cells and adipose tissue, individuals with compromised function of these tissues drive greater infection and severity in patients with COVID-19. Global health experts estimate that one in five individuals worldwide could be at risk for severe COVID-19, due to underlying health conditions. There is a great need for a rapid, specific, cost-effective test for monitoring the infected individuals. Even though a 15- minute, antigen test was made available by Abbott recently, it seems that the schools, colleges, and business establishments lack the ability to use these tests effectively to keep their businesses open safely. Management of the infected individuals seems to be based on clinical symptoms that manifest as the disease progresses. The US Food & Drug Administration (FDA), has created a special emergency program for possible therapies, the Coronavirus Treatment Acceleration Program (CTAP). The program uses every available method to move new and emerging treatments as quickly as possible, keeping in mind the safety and efficacy of such therapies. According to the WHO report, there are currently more than 150 COVID-19 vaccine candidates under development. Several vaccines are in Phase 3 clinical trials. In an unprecedented effort, one of the experimental monoclonal antibody cocktails of Regeneron was used for therapeutic purposes when the US president was tested positive for COVID-19. There are no drugs or other therapeutics approved by the US FDA to prevent or treat COVID-19. The National Institutes of Health (NIH) have published interim guidelines for the medical management of COVID-19. In the absence of a cure, the only choice we all have is to follow the best practices recommended by the public health experts—use of face masks (coverings), frequent hand washing with soap, contact tracing of infected individuals, and quarantining COVID-19 positive individuals, till they are free of the highly infectious virus.