Several coronaviruses (CoVs) have been identified as human pathogens, including the
α-CoVs strains HCoV-229E and HCoV-NL63 and the β-CoVs strains HCoV-HKU1 and HCoV-OC43.
SARS-CoV, MERS-CoV, and SARS-CoV-2 are also classified as β-coronavirus. New SARS-CoV-2 spike
genomic variants are responsible for human-to-human and interspecies transmissibility, consequences
of adaptations of strains from animals to humans. The receptor-binding domain (RBD) of SARS-CoV-2
binds to receptor ACE2 in humans and animal species with high affinity, suggesting there have been
adaptive genomic variants. New genomic variants including the incorporation, replacement, or
deletion of the amino acids at a variety of positions in the S protein have been documented and
are associated with the emergence of new strains adapted to different hosts. Interactions between
mutated residues and RBD have been demonstrated by structural modelling of variants including
D614G, B.1.1.7, B1.351, P.1, P2; other genomic variants allow escape from antibodies generated by
vaccines. Epidemiological and molecular tools are being used for real-time tracking of pathogen
evolution and particularly new SARS-CoV-2 variants. COVID-19 vaccines obtained from classical and
next-generation vaccine production platforms have entered clinicals trials. Biotechnology strategies
of the first generation (attenuated and inactivated virus–CoronaVac, CoVaxin; BBIBP-CorV), second
generation (replicating-incompetent vector vaccines–ChAdOx-1; Ad5-nCoV; Sputnik V; JNJ-78436735
vaccine-replicating-competent vector, protein subunits, virus-like particles–NVX-CoV2373 vaccine),
and third generation (nucleic-acid vaccines–INO-4800 (DNA); mRNA-1273 and BNT 162b (RNA
vaccines) have been used. Additionally, dendritic cells (LV-SMENP-DC) and artificial antigenpresenting (aAPC) cells modified with lentiviral vector have also been developed to inhibit viral
activity. Recombinant vaccines against COVID-19 are continuously being applied, and new clinical
trials have been tested by interchangeability studies of viral vaccines developed by classical and
next-generation platforms.
