COVID-19: VARIANTS, VACCINES, AND ADVERSE REACTIONS
Keywords:Vaccines, COVID-19, Immunology, Infectious diseases, Approved vaccines
Coronavirus Disease 2019 (COVID-19) not only jeopardized the health condition of humankind but also bruised the economy. Researchers found several dominant and predominant strains of the coronavirus and variants, in which B.1.1.7, B.1.351, and P.1 being the most prevalent. In all the variants of severe acute respiratory syndrome coronavirus 2, modifications occur in the spike protein deciphering variants that differ based on characteristics and properties such as the extent of virulence, severity of the disease, or probability of reinfection. The development of a vaccine against the pandemic causing COVID-19 is considered a major milestone in the history of vaccines due to the speed at which the vaccine was made. The vaccine against COVID-19 vaccines are classified under nucleic acid vaccines, protein-based vaccines, viral vector vaccines, and whole virus vaccines. At present, there are 22 vaccines approved under the category of emergency use authorization. COVID-19 prevention has been the main principle behind early vaccine availability, although none of the approved vaccine candidates have completed large scale clinical trials to evaluate the efficacy. This review presents a brief idea on types of COVID-19 vaccines, approved vaccines, and vaccine candidates under development.
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