Coronavirus-A Crippling Affliction to Humans.

Coronaviruses hold idiosyncratic morphological features and functionality. The members of this group have a remarkable capability of infecting both animals and humans. Inimitably, the replication of the RNA genome continues through the set of viral mRNA molecules. Coronaviruses received the least attention until 2003 since they caused only minor respiratory tract illnesses. However, this changed exclusively with the introduction of zoonotic SARS-CoV in 2003. In 2012, MERS-CoV emerged and confirmed this group of viruses as the major causative agents of severe respiratory tract illness. Today, Coronavirus Disease 2019 (i.e., COVID-19) has turned out to be a chief health problem that causes a severe acute respiratory disorder in humans. Since the first identification of COVID-19 in December 2019 in Wuhan, China, this infection has devastatingly spread all around the globe leading to a crippling affliction for humans. The strain is known as the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and WHO (the World Health Organization) has termed this new pandemic disease as Coronavirus Disease (COVID-19). COVID-19 is still spreading, with an estimated 136 million confirmed cases and more than 2.94 million deaths worldwide so far while the pandemic is still going on. In the current scenario, there is no particular treatment for COVID-19, however remarkable efforts for immunization and vaccine development can be observed. Therefore, the execution of precautions and proper preventive measures are indispensable to minimize and control the community transmission of the virus. This review summarizes information about the pathophysiology, transmission, symptoms, and the host defense mechanism as well as immunization and vaccine development against COVID-19.