SARS-CoV-2 vaccines and their challenges against the variants

Abstract

The coronavirus disease 2019 (COVID-19) pandemic has lead to the several researches for the development of the new severe acute respiratory syndrome corona virus 2 (SARSCoV- 2) vaccines, namely mRNA vaccine, viral vector vaccine, recombinant protein vaccine and inactivated vaccine, with an objective to achieve the response which include production of neutralizing antibodies, generation of a T-cell response, and avoidance of immune-enhanced disease. Over a course of time, the SARS-CoV-2 virus has evolved and lead to mutations; the virus with one or more new mutations is referred to as a “variant” of the original virus. All new strains (P.1 from Brazil, B.1.351 from South Africa, B.1.1.7 from the UK and B.1.617 from India) have mutations in the spike protein, resulting in the threat to the effectiveness of the current available first generation vaccines. Hence, there might be the need of the development of the modified next generation of vaccines, which take care of all those variants. Nevertheless, the current first generation vaccines may still provide satisfying immunity against SARS-CoV-2 variants. Most vaccines are expected to provide protection against hospitalizations/deaths from these variants and a booster vaccine against these variants is likely to be effective. Hence, the current vaccination must proceed. As we are aware that the more the virus spreads, the more variants are likely to appear. In order to stop the spread of SARS-CoV-2 variants, it is important to get the vaccines once it is available and not to forget about the need to wash hands frequently, keep at least 1m distance from others and wear a mask. With the development of the effective SARS-CoV-2 vaccines and implementation of public health measures, we can surely defeat SARS-CoV-2 virus in COVID-19 battle and end this pandemic.

Structural and functional insights into the spike protein mutations of emerging SARS-CoV-2 variants

“…RBD of S protein permits the virus entry into the host cell receptor. RBD has extensively been studied as an anti-SARS-CoV-2 drug target and vaccine candidate [23]. The FP, located in the S2 subdomain, comprising 15-20 residues, plays a vital role in mediating membrane fusion with the hACE2.…”

“…A sub-variant of Delta housing the substitution at K417N (also present in Beta variant) was nicknamed "Delta plus K417N" (AY.1) on 14 June 2021 [135]. The emergence of this variant has raised concern about the likelihood of immunity evasion and reinfection [23].…”

Development of COVID 19 vaccine: A summarized review on global trials, efficacy, and effectiveness on variants

“…S Pfizer (BNT162b2) Gamaleya (Sputnik V) Novavax NVX-CoV2373 Covaxin (Bharat Biotech) 1 Original Wuhan reference strain China, December 2019 References strain 55–81% (Voysey et al., 2021) [ 23 ] 66% (Tehrani and Sajadi, 2021) [ 32 ] 95% (Polack et al., 2020) [ 48 ] 91.6% (Logunov et al., 2021) [ 41 ] 89.7% (Heath et al., 2021) [ 60 ] 77.8% (Ella et al., 2021) [ 68 ] 2 B.1.1.7 (Detected in UK) 20I/501. Y. V1 (Alpha) United Kingdom 69del,70del,144del N501Y, A570D, D614G, S982A, D1118H, K1191 N, P681H, T716I 74.5% (Davies et al., 2021) [ 26 ] Unknown ∗93.7% effectiveness (Lopez Bernal et al., 2021) [ 30 ] Unknown 85.6% efficacy (Heath et al., 2021) [ 60 ] Unknown 3 B.1.351 (Detected in SA) 20H/501.V2 (Beta) South Africa D80A, D215G, 241del, 242del, 243del, N501Y, D614G, A701V, K417 N, E484K 10 (Madhi et al., 2021) % [ 28 ] 64–66% in USA (Shrestha, 2021) [ 33 ] ∗95% effective against severe disease and death [ 34 ] Virus-neutralizing activity with 3.1-fold (Gushchin et al., 2021) [ 42 ] 60.1% (Mahase, 2021b) [ 61 ] Unknown 4 B.1.617.2 Delta Variants 21A/S:478K (Delta) India L452R, D6...…”

“…However, the efficacy for preventing mild to moderate or critical and severe COVID 19 patients was 72% in the United States (US), 64% in South Africa (SA) [ 32 ]. For South Africa dominated Beta variant (B.1.3.5.1) was reported to have 64% ( Table 2 ) protection against moderate to severe or critical COVID 19 disease, and over 66% ( Table 2 ) showed protection against moderate to severe disease in the USA (primarily the Wuhan-1 variants with mutation D614G), at least 29 days after vaccine intervention [ 33 ]. In July J&J was reported to be effective against the highly contagious Delta variant but had only a small decrease in potency compared with the original SARS CoV2 strain, nevertheless, the first evaluation of the Ad26.COV2-S vaccine against Delta in real life was 71% Table 2 effective against hospitalization and 95% effective against death according to data released from J&J [ 34 ].…”

Advanced Plasmonic Nanoparticle-Based Techniques for the Prevention, Detection, and Treatment of Current COVID-19

“…However, one of the sub-variant of Delta housing the substitution at K417N called Delta plus K417N (AY.1), also present in Beta variant, has appeared on June 2021 [ 287 ]. As this variant emerged, a concern has raised about the likelihood of immunity evasion and reinfection [ 288 ]. The three variants L452R, E484Q, and T478K have occurred in the S RBD while P681R occurred in the cleavage site between S1 and S2.…”