and L452R. The binding of the S protein could be made easier by the latter three mutations [36]. B.1.526 (20C/S:484K) and B.1.525 (20A/S:484K) These variants were first identified in New York, USA. The notable mutations are E484K and S477N. While E484K decreases antibody response, S477N increases the attachment process [34]. Double mutant variant (B.1.617) This variant is first detected in India. As two mutations are seen in the same virus, this variant is called a “double mutant” variant. There was a significant increase in COVID-19 cases in India. The first case in the USA was identified in San Francisco on April 5, 2021. The notable mutations are E484Q and L452R. These variants are at increased risk of transmission and also resistant to vaccination. According to Indian Council of Medical Research Virology Lab, Bharat Biotech’s COVAXIN vaccine has been found to effectively neutralize the infection, and is 78% effective against the double mutant variant [37-39]. Triple mutant variant (B.1.618) In addition to E484Q and L425R in double mutant variants, the new triple variant discovered on April 20 2021, is characterized by the deletion of two amino acids, H146del and Y145del in the S protein. As of April 21 2021, a total of 1,189 samples were tested positive in Maharashtra, Delhi, West Bengal and Chhattisgarh, India. Similar to other variants, triple mutant variants have higher transmissibility. Data show that two of the three mutations in this variant are resistant to antibodies and also possess the ability to escape the body’s natural acquired immunity to COVID-19, and as such, do not know much about the vaccine effectiveness [40, 41]. 20A.EU1/ S:A222V The 20A.EU1 variant has non-terminal domain (NTD) mutations which do not play a direct role in receptor binding or membrane fusion. This variant was initially identified on 20 June, 2020 in Spain but rapidly spread across Europe and many countries [42]. 20A.EU2 The 20A.EU2 variant was found in France in June 2020 and has become the second dominant variant in Europe. The notable mutations are S477N, E484K, and N501Y, which demonstrated slight increase in ACE2 binding, resistance to multiple antibodies and convalescent sera. They confer modest increase in infectivity as measured by soluble mACE2 [43]. 20A/S:439K The 20A/S:439K variant was initially found in Ireland. This variant has S:N439K mutation with the deletions of amino acids at positions 69 and 70 of S proteins that results in an increase in ACE2 binding, resistance to antibodies and convalescent plasma [12]. 20A/S:98F The 20A/S:98F variant has S:98F mutation which was found predominantly in Belgium and Netherlands [12]. 20C/S:80Y The 20C/S:80Y variant had 18 nucleotide mutations, possibly 322 Articles © The authors | Journal compilation © J Clin Med Res and Elmer Press Inc™ | www.jocmr.org COVID-19 Vaccines Versus the Variants J Clin Med Res. 2021;13(6):317-325 related to apolipoprotein B editing complex (APOBEC)-like editing within the host which are found in at least 10 countries in Europe [12]. 20B/S:626S The 20B/S:626S variant has S:626S mutation. This variant is found in 15 countries of Europe that is predominantly seen in Norway, Denmark, and the UK [12]. 20B/S:1122L The 20B/S:1122L variant has S:V1122L mutation and is found predominantly in Sweden, Norway, and Denmark [12]. N440K According to the latest report, another new variant N440K with the mutation in the S protein has emerged, which resulted in the sudden increase in cases in Andhra Pradesh, India. The Center for Cellular and Molecular Biology found that this variant has enhanced binding to ACE2 receptors, 10 to 1,000 folds more transmissible and resistant to class 3 monoclonal antibodies C135 and REGN10987. There are several documented cases of reinfection with the presence of anti-SARS-CoV-2 antibodies indicating the possibility of loss of neutralizing activity of antibodies elicited by vaccines [44, 45]. COVID-19 Vaccines Versus the Variants At the time of this paper, there were 91 COVID-19 vaccines in the clinical development stage and 184 COVID-19 vaccines in pre-clinical developmental stage [46]. Several platforms have been utilized in the development of these vaccines which include protein subunit, viral vector (replicating and non-replicating), deoxyribonucleic acid (DNA), inactivated virus, RNA, virus like particle and live attenuated. As of now, the Food and Drug Administration (FDA) has approved three vaccinations for emergency use in the USA, and data suggest that the mRNA vaccines reasonably provide protection against the B.1.1.7 COVID-19 variant. The mRNA vaccines, Pfizer and Moderna were authorized in the USA before the identification of the South African variant (B.1.351 or 20H/501Y. V2) strain in the country. According to the latest studies, these two vaccines elicited lower neutralizing antibodies than that of the previous strains. Novavax, Janssen, and Astra-Zeneca conducted trials in South Africa that have dominant B.1.351 mutated strains. These studies demonstrated the lower vaccine efficacy compared to that of the other variants where this strain was not dominant [47]. Vaccine efficacy for Brazilian variant (B.1.1.28) has not yet been reported. B.1.351 and P.1 consist of similar receptor binding mutations and hence, the vaccine efficacy against P.1 strain is assumed to be similar to B.1.351. As the