Strategies and Challenges in the Development of Coronavirus Disease-2019 Vaccine.
The coronavirus is an enveloped and positive sense single stranded ribonucleic acid (RNA) genome. It belongs to the Beta coronavirus genus containing 30 kb genome with 14 open reading frames. The ORFs includes four viral structural proteins: Membrane (M), Spike (S), Nucleocapsid (N) and Envelope (E) protein. The S protein is functionally composed of two subunits, S1 and S2 . During infections, host cell proteases process the S protein at the S1/S2 cleavage site. Proteolytically processed S protein cleaves into two subunits, the N-terminal at the S1 subunit and the C-terminal of the S2 subunit. The S1 subunit consists of N-terminal, signal peptide, and receptor binding domains.
Coronavirus can infect a range of host species such as animals, birds and humans. Different CoVs like SARSCoV, MERS-CoV and SARS-CoV-2 have intricate host receptor recognition patterns, which indicate the structural diversity in the receptor binding domain of the S protein. According to WHO guidelines, the COVID-19 infected patients should receive supportive body system-focused therapies like fluid therapy, oxygen therapy and antibiotics.
The COVID-19 pandemic emerged as wide spread SARS-CoV-2 infection in December 2019, according to most estimates. Several challenges exist in the development of vaccines against COVID-19 as the novel SARS-CoV-2 is undergoing several genomic changes, even as of the time of this writing. Developed vaccine candidates include approaches with inactivated viruses, live attenuated viruses, virus nucleic acid-based vaccine, and protein subunit vaccines. All are in different clinical phases. Moderna’s vaccine.
Epidemiol Open J. 2021; 6(1): 1-10. doi: 10.17140/EPOJ-6-122