Strategies and Challenges in the Development of Coronavirus Disease-2019 Vaccine

The novel coronavirus infection (coronavirus disease-2019 (COVID-19)) emerged from Wuhan in the Hubei Province of China in late 2019. Millions of people were infected with COVID-19 pandemic due to the long incubation period of the virus inside the human body and the dearth of available treatments or vaccines. High transmission rates created havoc, which highlighted the urgent need for effective interventions to stop the spread and clinical impact of the virus on patients and populations. Previous research on severe acute respiratory syndrome coronavirus (SARS-CoV) provides information on vaccination strategies that could inform how governments approach the elimination of this novel coronavirus. Numerous efforts have been made to develop vaccines against Middle East respiratory syndrome (MERS) and SARS. The spike glycoprotein or S protein is the critical target for most of the drugs and vaccines against coronavirus. The virus uses the spike (S) protein for entering the host cell, by interacting with the receptor called angiotensin converting enzyme-2 (ACE2). Various vaccine platforms are available such as nucleic acid vaccine, protein-based vaccines, virus-vectored vaccines and live or attenuated vaccines, with each having their advantages and disadvantages. This review focuses on the overview of different vaccine candidates used, those currently in development, and the challenges encountered while developing effective vaccines.