COVID-19 pandemic: potential phase III vaccines in development

Abstract

By the end of the year 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated in China. With the passage of more than half of the year 2020, the virus has spread worldwide, making it the worst pandemic of our lifetime. The spread of the virus is controlled by imposing lockdown, which has led to severe economic slowdown around the globe. Coronaviruses are zoonotic as they spread from animals to humans. Factors such as rapid urbanization and poultry farming have permitted intermixing of species leading to crossing barriers and spreading of viruses to humans. Coronavirus disease (COVID-19) caused by SARS-CoV-2 is acute in most people, but it may progress to severe respiratory distress, especially in people with weak innate immunity leading to death. It is a contagious infection with the death toll mounting to above seven lakhs in the world, so there is an urgent need to find the vaccine to cure the virus, as there is no licensed drug or vaccine available. Global collaborations and increased research efforts among the scientific community have led to more than 150 clinical trials globally. This review discusses the SARS-CoV-2 replication mechanism and potential vaccine candidates in phase III COVID-19 clinical trials. Measures adopted to accomplish the fast pace of the COVID-19 trials are highlighted with an update on possible new drug targets or strategies to fight off the virus.