SARS-CoV-2 variants and COVID-19 vaccines: Current challenges and future strategies

Figures & data

Figure 1. The global trend of confirmed COVID-19 cases/deaths (A) and the WHO regional trend of confirmed COVID-19 cases (B). The data used in this figure was collected from WHO COVID-19 Dashboard (https://covid19.who.int/) and presented by cases per weekly. The data were obtained on April 20, 2022.

Table 1. Currently and previously designated variants of concern (VOC) by WHO.

WHO label	Pango lineage	Nextstrain clade	GISAID	Old CoVariants names	Earliest documented samples^a		Status
					Place	Time
Alpha (α)	B.1.1.7	20I (Alpha, V1)	GRY, GR/501Y.V1	20I/501Y.V1	United Kingdom	Sep-2020	Previously
Beta (β)	B.1.351	20H (Beta, V2)	GH/501Y.V2	20H/501Y.V2	South Africa	May-2020	Previously
Gamma (γ)	P.1	20J (Gamma, V3)	GR/501Y.V3	20J/501Y.V3	Brazil	Nov-2020	Previously
Delta (δ)	B.1.617.2	21A (Delta)	G/452R.V3	21A/S:478K	India	Oct-2020	Currently
Omicron (ο)	B.1.1.529	21K (Omicron)	GR/484A		South Africa	Nov-2021	Currently

a The data were obtained from outbreak.info website (available at https://outbreak.info/situation-reports) or WHO website (available at https://www.who.int/activities/tracking-SARS-CoV-2-variants/tracking-SARS-CoV-2-variants). Accessed April 20, 2022.

Figure 2. The evolutionary relationships of SARS-CoV-2 from the ongoing COVID-19 pandemic. (A) The data used herein were obtained from 2716 genomes sampled between Dec 2019 and Dec 2021. Each genomic sample was showed by a solid dot and colored by Emerging Lineages. (B) The frequencies of variants sampled between Jan 2021 and Dec 2021 were presented by different colors. All of data was obtained on April 20, 2022.

Figure 3. Mutation prevalence across VOC and VOI lineages and their geographical distribution on Receptor Binding Domain (RBD) of Spike protein. (A) Mutations with >95% prevalence in at least one lineage. The data were obtained from https://outbreak.info/situation-reports and accessed on Dec 14, 2021. (B) Showing mutations in Spike protein RBD present in at least 20% of countries for visualization purposes. The data were collected from COVID-Miner website (https://covid-miner.ifo.gov.it/app/countries) and accessed on Dec 14, 2021.

Table 2. Characteristics of SARS-CoV-2 VOCs and VOIs.

Lineage	Spike protein mutations^a	Attributes	Reference
B.1.1.7 (Alpha)		50% increased transmission [10]; HR (95%CI) of hospitalization, ICU admission, and mortality for alpha variant vs. wild-type virus are 1.53 (1.49–1.57), 1.74(1.35–2.09), and 1.37 (1.15–1.60), respectively [11]. Potential increased mortality and critical care unit admission [12] No impact on susceptibility to EUA monoclonal antibody treatments [13] B.1.1.7 is refractory to neutralization by most monoclonal antibodies against the N-terminal domain of the spike protein and is relatively resistant to a few monoclonal antibodies against the receptor-binding domain [14]. A two-dose regimen of the NVX-CoV2373 vaccine administered to adult participants conferred 89.7% protection against SARS-CoV-2 infection and an efficacy of 86.3% against the B.1.1.7 (or alpha) variant [15]. Effectiveness after two doses of BNT162b2 or ChAdOx1 nCoV-19 vaccine was 93.7% or 74.5% [16,17]. Susceptible to neutralizing antibodies elicited by ancestral Spike vaccines [18]	[10–18]
B.1.351 (Beta)		50% increased transmission [19]; HR (95%CI) of hospitalization, ICU admission, and mortality for Beta variant vs. wild-type virus are 2.16 (1.19–3.14), 2.23(1.31–3.15), and 1.50 (1.26–1.74), respectively [11]. Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment [13], but other EUA monoclonal antibody treatments are available [20] Reduced but still significant neutralization against the full B.1.351 variant following mRNA-1273 vaccination [21] ChAdOx1 nCoV-19 vaccine efficacy against this variant was 10.4% (95% CI, −76.8 to 54.8) [22]. BNT162b2 vaccine offers protection against the B.1.351 variant [17]. B.1.351 variant is not only refractory to neutralization by most monoclonal antibodies against the N-terminal domain but also by multiple individual monoclonal antibodies against the receptor-binding motif of the receptor-binding domain [14]	[11,13,14,17,19,20,22]
P.1 (Gamma)		HR (95%CI) of hospitalization, ICU admission, and mortality for Gamma variant vs. wild-type virus are 1.71 (0.9–2.52), 1.94(1.71–2.18), and 1.06 (0.17–1.96), respectively [11]. Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment [13], but other EUA monoclonal antibody treatments are available [20] Reduced neutralization by multiple neutralizing monoclonal antibodies and convalescent and vaccine sera [23] BNT162b2 vaccine offers protection against the P.1 variant [17].	[11,13,17,20,23]
B.1.617.2 (Delta)		Highly transmissible in indoor sports settings and within households [24] HR (95%CI) of hospitalization, ICU admission, and mortality for alpha variant vs. wild-type virus are 2.08 (1.77–2.39), 3.35 (2.50–4.20), and 2.33 (1.45–3.21), respectively [11]. Reduced BNT162b2 vaccine efficacy akin to the B.1.351 and increased transmissibility beyond the B.1.1.7 [25] Potential reduction in neutralization by some EUA monoclonal antibody treatments [13,20] Effectiveness after two doses of BNT162b2 or ChAdOx1 nCoV-19 vaccine was 88.0% or 67.0% among patients with the delta variant [16]. One dose of both AstraZeneca and Pfizer vaccine is only 33% effective against the variant [26].	[11,13,16,20,24–26]
B.1.1.529 (Omicron)		Compared with Delta variant, the transmission of Omicron is enhanced, but the hospitalization, ICU admission, and mortality are reduced [27,28]. Omicron still required the ACE2 receptor to infect but had extensive escape of Pfizer elicited neutralization [27]. A 41-fold reduction of neutralization level of sera against Omicron infection [29]. Omicron variant is associated with substantial ability to evade immunity from prior infection [30]	[27–30]
B.1.621 (Mu)		Mu is likely to be less transmissible than Delta [31]. Two doses of mRNA-1273 vaccine were 90.4% (73.9–96.5%) against Mu [32]. Neutralizing antibody response to the Mu variant was 2.3-fold lower in comparison to the WA1 strain in day 42 sera [33]. BNT162b2 mRNA vaccine has 76% neutralizing effectiveness against the Mu variant [34].	[31–34]
C.37 (Lambda)		Moderately reduced sensitivity to neutralization by convalescent sera and REGN10987 monoclonal antibody [35]. slightly reduced sensitivity to BNT162b2, mRNA-1273, and CoronaVac-elicited antibodies, while retaining full sensitivity to REGN10933 [35,36].	[35,36]

a Mutations of spike protein appearing in at least 75% of sequences, the darker the purple, the more frequent the mutation. The mutation of concern or mutation of interest was showed as red or orange word. Data were available at https://outbreak.info/. Accessed on 26 December 2021.

EUA, Emergency Use Authorization.

Figure 4. The locations of the Omicron mutations in the spike protein showing amino acid substitutions (yellow), deletions (red), and insertions (green). In this trimeric structure, two monomers (gray and light blue) have their receptor-binding domains in the "down" conformation while one (dark blue) is in the "up" or "open" conformation. Mutation data from WHO structure from PDB: 6VYB (Opabinia regalis [39,40]).

Figure 5. Forest plots of COVID-19 vaccine effectiveness on variants of concern (randomized evidence). The data were collected from COVID-NMA (https://covid-nma.com/vaccines/variants/index.php), Clinicaltrials.gov (https://clinicaltrials.gov/ct2/home). Accessed on Aug 16, 2021.

Table 3. Clinical trials on evaluating the effectiveness of COVID-19 vaccines on VOCs.

Variants	Vaccine (Type)	Clinical trial (Design)	Comparisons		Participants	Sample size^a	Primary outcome	Reference
			Intervention 1	Intervention 2
Alpha	ChAdOx1 (Non replicating viral vector)	NCT04400838, ISRCTN 15281137 (RCT Phase 2/3)	2 IM doses (5 × 10^10 vp) ChAdOx1 nCoV-19 vaccine on Days 0/28	2 IM doses of MenACWY control vaccine on Days 0/28	Adults seronegative at baseline enrolled at 19 study sites in UK	ChAdOx1 (n = 4244), Control (n = 4290)	(1) Assess the efficacy of the candidate ChAdOx1 nCoV-19 against COVID-19 in adults aged 18 years and older; (2) Assess the safety of the candidate vaccine ChAdOx1 nCoV-19 in adults	[53]
	NVX-CoV2373 (Protein subunit)	NCT04583995, EudraCT 2020-004123-16 (RCT Phase 3)	2 IM doses of 5 µg NVX-CoV2373, 21 days apart	2 IM doses of placebo, 21 days apart	Adults 18 to 84 years old who were healthy or had stable chronic medical conditions with no history of COVID-19 at 33 centers in the UK.	5 µg NVX-CoV2373 (n = 7020), Placebo (n = 7019)	Efficacy of the NVX-CoV2373 vaccine against the first occurrence of virologically confirmed symptomatic mild, moderate, or severe Covid-19 with onset at least 7 days after the second dose among participants who were seronegative at baseline, as determined by the results of testing for anti–nucleocapsid antibody.	[15]
Beta	ChAdOx1 nCoV-19 (Non replicating viral vector)	NCT04444674 (RCT Phase 1/2)	2 IM doses of 5 × 10^10vp ChAdOx1 nCoV-19, D0/28	2 IM doses of placebo, D0/28	Healthy adult volunteers that were HIV-negative and SARS-CoV-2 infection-free in 7 centers in South Africa	ChAdOx1 (n = 750), Placebo (n = 714)	Efficacy against nucleic acid amplification test-confirmed symptomatic Covid-19 with onset more than 14 days after the second injection in participants who were seronegative at randomization.	[22]
	Ad26.COV2.S (Non replicating viral vector)	NCT04505722 (RCT Phase 3)	1 IM dose Ad26.COV2.S (5 × 10^10 vp) day 0	1 IM dose 0.9% sodium chloride solution day 0	Adults >18 years of age at 213 centers in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa and USA	Ad26.COV2.S (n = 2473), Placebo (n = 2496)	Vaccine efficacy against moderate to severe–critical coronavirus disease 2019 (Covid-19) with an onset at least 14 days and at least 28 days after administration among participants in the per-protocol population who had tested negative for SARS-CoV-2.	[54]
	NVX-CoV2373 (Protein subunit)	NCT04533399 (RCT Phase 2a/b)	2 IM doses of 5 mcg NVX-CoV2373 with 50 mcg Matrix-M1 adjuvant, 21 days apart	2 IM doses of saline placebo, 21 days apart	HIV-negative adults (18 to 84 years) and medically stable HIV-positive adults (18 to 64 years) at 16 sites in South Africa	NVX-CoV2373 (n = 1357), Placebo (n = 1327)	(1) Occurrence of unsolicited adverse events; (2) solicited local and systemic adverse events evaluated via reactogenicity diary for 7 days following each vaccination; (3) confirmed symptomatic mild, moderate, or severe Covid-19 in participants seronegative to SARS-CoV-2 at baseline occurring 7 days after receipt of the second study vaccine	[44]
	BNT162b2 (RNA based vaccine)	NCT04368728 (RCT Phase 2/3)	2 IM doses of 30 mcg, 21 days apart	2 IM doses of placebo, 21 days apart	Children, adolescents, and adults, with no history or SARS-CoV-2 infection at 152 sites in Argentina, Brazil, Germany, South Africa, Turkey, and USA	BNT162b2 (n = 291), Placebo (n = 276)	Vaccine efficacy against laboratory-confirmed COVID-19 and safety data, both up to 6 months post-vaccination	[55]
Delta	BBV152 (Inactivated virus)	NCT04641481 (RCT Phase 3)	2 IM doses of 6 mcg, 28 days apart	2 IM doses of placebo, 28 days apart	Adults with no history of SARS-CoV-2 infection who were healthy or had stable chronic medical conditions at 25 centers in India	BBV152B (n = 8471), Placebo (n = 8502)	Efficacy of the BBV152 vaccine in preventing a first occurrence of symptomatic COVID-19 with onset at least 14 days after the second dose in the per-protocol population composed of participants.	[56]

HIV, human immunodeficiency virus; IM, intramuscular; NCT, ClinicalTrials.gov identifier number; RCT, randomized controlled trial.

a The sample size only includes the participants with COVID-19 caused by the B.1.1.7 (Alpha), B.1.351 (Beta), or B.1.617.2 (Delta) variant.

Table 4. Impact of the SARS-CoV2 variants of concern (VOC) on the COVID-19 pandemic in the world (as of December 2021) [68].

WHO label variant/Pango^a lineage/Country/Time	Mutations in spike protein	Transmission/Vaccine efficacy	Impact on disease severity	Spread in countries	Reference
B.1.1.7 Alpha/UK/ September-2020	69del, 70del, 144del, E484K, S494P*, N501Y, A570D, D614G, P681H, T716I, S982A, D1118H, K1191N	Increased/Not decreased for NVX-CoV2373 (85.6%)	Increased	193	[10,69,70]
B.1.351 Beta/South Africa/ December-2020	D80A, D215G, 241del, 242del, 243del, K417N, E484K, N501Y, D614G, A701V	Increased/decreased	Increased	141	[10,47,71–74]
P.1/B.1.1.28.1 Gamma/Brazil/December-2020	L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, D614G, H655Y, T1027I	Increased/decreased	Increased	91	[10,23,72,75,76]
B.1.617.2^b Delta/India	T19R, (G142D), 156del, 157del, R158G, L452R, T478K, D614G, P681R, D950N	Increased/decreased	Increased	170	[16,24,77–81]
B.1.1.529 Omicron South Africa November 2021	RBD—K417N, N440K, G446S, S477N, T478K, E484A, Q493K, G496S, Q498R, N501Y, Y505H (32 mutations in spike protein)	Increased/decreased	Decreased	Not known	[27,28,39,82]

a PANGO—Phylogenetic Assignment of Named Global Outbreak.

b Delta variant is currently the world’s dominant COVID-19 variant.

Figure 6. Current challenges and future strategies. An illustration depicting the current challenges to control the Covid-19 pandemic due to emergence of VOCs and various strategies control the combat the current and future pandemics due to corona viruses.

Figure 7. Illustration showing the possibility of SARS-CoV-2 either completely disappearing from the globe or more likely becoming endemic and causing mild disease and need of seasonal vaccination similar to influenza.

Davies NG, Abbott S, Barnard RC, et al. Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England. Science (New York, NY). 2021;372(6538):372. doi:10.1126/science.abg3055.

 Google Scholar

Lin L, Liu Y, Tang X, et al. The disease severity and clinical outcomes of the SARS-CoV-2 variants of concern. Front Public Health. 2021;9:775224. doi:10.3389/fpubh.2021.775224.

 PubMed Web of Science ®Google Scholar

Patone M, Thomas K, Hatch R, et al. Mortality and critical care unit admission associated with the SARS-CoV-2 lineage B.1.1.7 in England: an observational cohort study. Lancet Infect Dis. 2021;21(11):1518–1528. doi:10.1016/S1473-3099(21)00318-2.

 PubMed Web of Science ®Google Scholar

FDA. Fact sheet for health care providers emergency use authorization (EUA) of bamlanivimab and etesevimab. Indianapolis, USA; 2021.

 Google Scholar

Wang P, Nair MS, Liu L, et al. Antibody resistance of SARS-CoV-2 variants B.1.351 and B.1.1.7. Nature. 2021;593(7857):130–135. doi:10.1038/s41586-021-03398-2.

 PubMed Web of Science ®Google Scholar

Heath PT, Galiza EP, Baxter DN, et al. Safety and efficacy of NVX-CoV2373 Covid-19 vaccine. N Engl J Med. 2021;385(13):1172–1183. doi:10.1056/NEJMoa2107659.

 PubMed Web of Science ®Google Scholar

Lopez Bernal J, Andrews N, Gower C, et al. Effectiveness of Covid-19 vaccines against the B.1.617.2 (Delta) variant. N Engl J Med. 2021;385(7):585–594. doi:10.1056/NEJMoa2108891.

 PubMed Web of Science ®Google Scholar

Zani A, Caccuri F, Messali S, et al. Serosurvey in BNT162b2 vaccine-elicited neutralizing antibodies against authentic B.1, B.1.1.7, B.1.351, B.1.525 and P.1 SARS-CoV-2 variants. Emerg Microbes Infect. 2021;10(1):1241–1243. doi:10.1080/22221751.2021.1940305.

 PubMed Web of Science ®Google Scholar

Shen X, Tang H, McDanal C, et al. SARS-CoV-2 variant B.1.1.7 is susceptible to neutralizing antibodies elicited by ancestral spike vaccines. Cell Host Microbe. 2021;29(4):529–539.e3. doi:10.1016/j.chom.2021.03.002.

 PubMed Web of Science ®Google Scholar

Pearson CA, Russell TW, Davie NG, et al. Estimates of severity and transmissibility of novel South Africa SARS-CoV-2 variant 501Y.V2. 2021.

 Google Scholar

FDA. Fact Sheet for Health Care Providers Emergency Use Authorization (EUA) of Regen-Covtm (Casirivimab and Imdevimab). New York, USA: U.S. Food and Drug Administration (FDA); 2021:57.

 Google Scholar

Wu K, Werner AP, Moliva JI, et al. mRNA-1273 vaccine induces neutralizing antibodies against spike mutants from global SARS-CoV-2 variants. bioRxiv: the preprint server for biology. 2021.

 Google Scholar

Madhi SA, Baillie V, Cutland CL, et al. Efficacy of the ChAdOx1 nCoV-19 Covid-19 Vaccine against the B.1.351 Variant. N Engl J Med. 2021;384(20):1885–1898. doi:10.1056/NEJMoa2102214.

 PubMed Web of Science ®Google Scholar

Wang P, Casner RG, Nair MS, et al. Increased resistance of SARS-CoV-2 variant P.1 to antibody neutralization. Cell Host Microbe. 2021;29(5):747–751.e4. doi:10.1016/j.chom.2021.04.007.

 PubMed Web of Science ®Google Scholar

Dougherty K, Mannell M, Naqvi O, et al. SARS-CoV-2 B.1.617.2 (Delta) variant COVID-19 outbreak associated with a gymnastics facility - Oklahoma, April–May 2021. MMWR Morb Mortal Wkly Rep. 2021;70(28):1004–1007. doi:10.15585/mmwr.mm7028e2.

 PubMed Web of Science ®Google Scholar

Wall EC, Wu M, Harvey R, et al. Neutralising antibody activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 vaccination. Lancet (London, England). 2021;397(10292):2331–2333. doi:10.1016/S0140-6736(21)01290-3.

 PubMed Web of Science ®Google Scholar

Iacobucci G. Covid-19: local councils initiate surge vaccination to tackle B.1.617.2 variant. BMJ. 2021;373:n1361. doi:10.1136/bmj.n1361.

 PubMedGoogle Scholar

Mahase E. Covid-19: hospital admission 50–70% less likely with omicron than delta, but transmission a major concern. BMJ. 2021;375:n3151. doi:10.1136/bmj.n3151.

 PubMed Web of Science ®Google Scholar

Vogel G, Kupferschmidt K. Early lab studies shed light on Omicron’s behavior. Science. 2021;374(6575):1543–1544. doi:10.1126/science.acz9878.

 PubMed Web of Science ®Google Scholar

Cele S, Jackson L, Khan K, et al. SARS-CoV-2 Omicron has extensive but incomplete escape of Pfizer BNT162b2 elicited neutralization and requires ACE2 for infection. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Pulliam JRC, van Schalkwyk C, Govender N, et al. Increased risk of SARS-CoV-2 reinfection associated with emergence of the Omicron variant in South Africa. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Xie X, Han JB, Ma G, et al. Emerging SARS-CoV-2 B.1.621/Mu variant is prominently resistant to inactivated vaccine-elicited antibodies. Zool Res. 2021;42(6):789–791. doi:10.24272/j.issn.2095-8137.2021.343.

 PubMed Web of Science ®Google Scholar

Katia B, Lina SS, Lei Q, et al. Effectiveness of mRNA-1273 against Delta, Mu, and other emerging variants. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Mehul S, Prabhu SA, Mengyun H, et al. Durability of immune responses to the BNT162b2 mRNA vaccine. bioRxiv: the preprint server for biology. 2021.

 Google Scholar

Kei M, Sundararaj SJ, Hideaki K, et al. Neutralizing efficacy of vaccines against the SARS-CoV-2 Mu variant. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Tada T, Zhou H, Dcosta BM, et al. SARS-CoV-2 Lambda variant remains susceptible to neutralization by mRNA vaccine-elicited antibodies and convalescent serum. bioRxiv: the preprint server for biology. 2021.

 Google Scholar

Acevedo ML, Alonso-Palomares L, Bustamante A, et al. Infectivity and immune escape of the new SARS-CoV-2 variant of interest Lambda. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Torjesen I. Covid-19: omicron may be more transmissible than other variants and partly resistant to existing vaccines, scientists fear. BMJ. 2021;375:n2943. doi:10.1136/bmj.n2943.

 PubMed Web of Science ®Google Scholar

Walls AC, Park YJ, Tortorici MA, et al. Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein. Cell. 2020;181(2):281–292.e6. doi:10.1016/j.cell.2020.02.058.

 PubMed Web of Science ®Google Scholar

Emary KRW, Golubchik T, Aley PK, et al. Efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine against SARS-CoV-2 variant of concern 202012/01 (B.1.1.7): an exploratory analysis of a randomised controlled trial. Lancet. 2021;397(10282):1351–1362. doi:10.1016/S0140-6736(21)00628-0.

 PubMed Web of Science ®Google Scholar

Sadoff J, Gray G, Vandebosch A, et al. Safety and efficacy of single-dose Ad26.COV2.S vaccine against Covid-19. N Engl J Med. 2021;384(23):2187–2201. doi:10.1056/NEJMoa2101544.

 PubMed Web of Science ®Google Scholar

Shinde V, Bhikha S, Hoosain Z, et al. Efficacy of NVX-CoV2373 Covid-19 vaccine against the B.1.351 variant. N Engl J Med. 2021;384(20):1899–1909. doi:10.1056/NEJMoa2103055.

 PubMed Web of Science ®Google Scholar

Thomas SJ, Moreira ED, Kitchin N, et al. Six month safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

Ella R, Reddy S, Blackwelder W, et al. Efficacy, safety, and lot to lot immunogenicity of an inactivated SARS-CoV-2 vaccine (BBV152): a, double-blind, randomised, controlled phase 3 trial. medRxiv: the preprint server for health sciences. 2021.

 Google Scholar

World Health Organization. Tracking SARS-CoV-2 variants. https://wwwwhoint/en/activities/tracking-SARS-CoV-2-variants/. 2021.

 Google Scholar

Collier DA, De Marco A, Ferreira I, et al. Sensitivity of SARS-CoV-2 B.1.1.7 to mRNA vaccine-elicited antibodies. Nature. 2021;593(7857):136–141. doi:10.1038/s41586-021-03412-7.

 PubMed Web of Science ®Google Scholar

Giles B, Meredith P, Robson S, et al. The SARS-CoV-2 B.1.1.7 variant and increased clinical severity-the jury is out. Lancet Infect Dis. 2021;21(9):1213–1214. doi:10.1016/S1473-3099(21)00356-X.

 PubMed Web of Science ®Google Scholar

Jangra S, Ye C, Rathnasinghe R, et al. SARS-CoV-2 spike E484K mutation reduces antibody neutralisation. Lancet Microbe. 2021;2(7):e283–e4. doi:10.1016/S2666-5247(21)00068-9.

 PubMedGoogle Scholar

Funk T, Pharris A, Spiteri G, et al. Characteristics of SARS-CoV-2 variants of concern B.1.1.7, B.1.351 or P.1: data from seven EU/EEA countries, weeks 38/2020 to 10/2021. Euro surveillance: bulletin. Europeen sur les maladies transmissibles = European Communicable Disease Bulletin. 2021;(16):2100348.

 Google Scholar

Sabino EC, Buss LF, Carvalho MPS, et al. Resurgence of COVID-19 in Manaus, Brazil, despite high seroprevalence. Lancet (London, England). 2021;397(10273):452–455. doi:10.1016/S0140-6736(21)00183-5.

 PubMed Web of Science ®Google Scholar

Charmet T, Schaeffer L, Grant R, et al. Impact of original, B.1.1.7, and B.1.351/P.1 SARS-CoV-2 lineages on vaccine effectiveness of two doses of COVID-19 mRNA vaccines: results from a nationwide case-control study in France. Lancet Reg Health Eur. 2021;8:100171. doi:10.1016/j.lanepe.2021.100171.

 PubMedGoogle Scholar

World Health Organization. Classification of omicron (B.1.1.529): SARS-CoV-2 variant of concern. https://wwwwhoint/news/item/26-11-2021-classification-of-omicron-(b11529)-sars-cov-2-variant-of-concern. 2021.

 Google Scholar

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files.