Another important mutation N501Y has shown an increased severity of the infection and high binding affinity of the spike protein to ACE 2 receptors, enhancing the viral attachment and subsequent entry into host cells (Cascella et?al., 2021). impartial vaccines; the stories of re-infections are generating more stressful conditions, and this needs further clinical evaluation. naturally occurring infection or vaccination and decrease the effectiveness of vaccines or therapeutics options. Classification systems for genetic variants have been established by the CDC (Center for Disease Control and Prevention) and the WHO (World Health Organization) independently for distinguishing the emerging VOCs and variants of interest (VOIs). The VOCs are classified by the WHO as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) (Wang et?al., 2021). All These strains have shown genetic modification in the S gene in comparison with the native Wuhan strain. The maximum number of mutations in S protein change the infection rate, severity, affinity with host receptor ACE2, and also the possibility to alter the effectiveness of neutralizing antibodies and vaccine efficacy. B.1.351 variants of SARS-CoV-2 have been identified in more than 40 countries at the global level, P.1 variants have been identified in 20 countries (Weisblum et?al., 2020). Most of the vaccines Thiolutin are produced for the early strain circulating at the global level. Therefore, some vaccines had reduced efficacy against the newly emerged SARS-CoV-2 variants. Nevertheless, The US FDA (Food and Thiolutin Drug Administration) stated that all FDA-approved vaccinations are still effective against circulating SARS-CoV-2 strains as of February 2021. Here, we will discuss SARS-CoV-2 New Variants and characteristic features and impact on the efficacy of different vaccines to understand their role in the transmissible and vaccine effectiveness. 2 Phylogenetic Analysis of SARS-CoV-2 Genome The Phylogenetic analysis of the SARS-CoV-2 genome with the related family members of SARS-CoV-2 from various organisms disclose that the genome of SARS-CoV-2 shows a high evolutionary association with Bat-SL-CoV. The phylogenetic tree is classified into three clades. Clade I consist of Bat-SL-CoV genomes and SARS-CoV with shared sequence identity ranging from more than 80% to 98%. Clade III consists of 11 complete genomes of a mixed form of coronavirus and MERS-CoV-2 genomes and shares the sequence identity from more than 75% to 85%. Clade II consists of 12 SARS-CoV-2 from India (CCMBOM9/2020/EPI ISL 495297), Korea (KCDC2059/2020/EPI ISL 481379), and two Bat-SL-CoV complete genomes and share sequence identity range from 85% to 99%, mainly the SARS-CoV-2 genomes isolated from human samples show a sequence identity range from 98% to 100%. In the analysis of the genome, there is no major divergence was observed in different countries as shown in Figure?1 . Open in a separate window Figure?1 The phylogenetic tree is generated using the latest complete genome sequences of different neighbours, MERS-CoV, Bat-SL-CoV, and SARS-CoV. The tree is divided into three clades according to the grouping of clusters. In Clade I: Bat-SL-CoV-2 and SARS-CoV were showing a close evolutionary relationship with each other. Clade II: A mixture of human and bat coronavirus including the MERS-CoV. Clade III: This clade represents all the SARS-CoV2 genomes isolated from humans, interestingly it is also observed that these genomes are showing a close evolutionary relationship with Bat-SL-CoV-2. 3.SARS-CoV-2 Vaccine and Variants 3.1 SARS-CoV-2 Vaccine The current pandemic situation is ongoing and a continuous threat to public health, and still, no anti- SARS-CoV-2 drugs or vaccine options have shown absolute health benefits (Singh et?al., 2020a; Singh et?al., 2020b). SARS-CoV-2 is very challenging due to age factors, gender differences, ecological factors, and its quick evolution (de Oliveira et?al., 2021). The investigations from various fields to come up with effective treatment options and vaccine developments are shown in Figure?2 (Marian et?al., 2021). The challenge of finding a final targeted drug is still difficult and ongoing, 405 therapeutic drugs are under investigation in various clinical stages and 242 vaccines are under clinical 139 research (Park et?al., 2021). Open in a separate window Figure?2 Approaches to SARS-CoV-2 Vaccine development: This is an Thiolutin overview Rabbit polyclonal to Caspase 3 of different platforms for viral vaccine development including (A) Live attenuated (B) Whole inactivated (C) Split inactivated (D) Use of synthetic peptides (E).