Impact of the delta variant on vaccine efficacy and response strategies
Open accessAbstract
INTRODUCTION: The Delta variant of SARS-CoV-2 has caused a new wave of the COVID-19 epidemic in many countries. It is the most infectious variant of SARS-CoV-2 to date, and its high infectivity means that a higher proportion of the population needs to be vaccinated to reduce the disease burden, which poses a substantial public health challenge. AREAS COVERED: The evolution of the Delta variant is reviewed, including an overview of the Delta Plus variant with a K417N mutation in the RBD, which may confer an improved immune evasion ability. Decreases in serum neutralizing antibody titers after vaccination against Delta were greater than those against Alpha but less than those against Beta. The protective efficacy of existing vaccines against the Delta variant have declined and is related to the number of doses and the time since vaccination. EXPERT OPINION: The currently used vaccines are effective against hospitalization/severe disease due to the Delta variant. Accelerating the popularization of vaccination, improving the coverage rate, and the implementation of intervention measures, such as wearing masks, are effective means to control the spread of the Delta variant and other variants. However, vaccination alone against SARS-CoV-2 without intervention measures may lead to continuous spread and the emergence of new variants.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia
Li, Q., Guan, X., Wu, P., Wang, X., Zhou, L., Tong, Y., Ren, R., Leung, K. S. M., Lau, E. H. Y., Wong, J. Y., et al. (2020) · New England Journal of Medicine · doi:10.1056/nejmoa2001316 · Cited by 16,575 · see citing works
Self-citationStructure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor
Lan, J., Ge, J., Yu, J., Shan, S., Zhou, H., Fan, S., Zhang, Q., Shi, X., Wang, Q., Zhang, L., et al. (2020) · Nature · doi:10.1038/s41586-020-2180-5 · Cited by 5,983 · see citing works
Self-citationCell entry mechanisms of SARS-CoV-2
Shang, J., Wan, Y., Luo, C., Ye, G., Geng, Q., Auerbach, A., & Li, F. (2020) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.2003138117 · Cited by 3,142 · see citing works
Effectiveness of COVID-19 vaccines against the B.1.617.2 variant
Bernal, J. L., Andrews, N., Gower, C., Gallagher, E., Simmons, R., Thelwall, S., Stowe, J., Tessier, E., Groves, N., Dabrera, G., et al. (2021) · doi:10.1101/2021.05.22.21257658 · Cited by 2,888 · see citing works
Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization
Planas, D., Veyer, D., Baidaliuk, A., Staropoli, I., Guivel-Benhassine, F., Rajah, M. M., Planchais, C., Porrot, F., Robillard, N., Puech, J., et al. (2021) · Nature · doi:10.1038/s41586-021-03777-9 · Cited by 1,992 · cited 1× · see citing works
“86 7 convalescent live virus (ED50) 26 / Alpha 4 / / / [8] BNT162b2 16 2 doses 3 / 16 / ChAdOx1 20 2 doses 5 / 9 / 8 convalescent live virus (ED50) 78 / WT 2.”
Haas, E. J., Angulo, F. J., McLaughlin, J. M., Anis, E., Singer, S. R., Khan, F., Brooks, N., Smaja, M., Mircus, G., Pan, K., et al. (2021) · The Lancet · doi:10.1016/s0140-6736(21)00947-8 · Cited by 1,564 · see citing works
Covid-19 Breakthrough Infections in Vaccinated Health Care Workers
Bergwerk, M., Gonen, T., Lustig, Y., Amit, S., Lipsitch, M., Cohen, C., Mandelboim, M., Levin, E. G., Rubin, C., Indenbaum, V., et al. (2021) · New England Journal of Medicine · doi:10.1056/nejmoa2109072 · Cited by 1,345 · see citing works
SARS-CoV-2 501Y.V2 escapes neutralization by South African COVID-19 donor plasma
Wibmer, C. K., Ayres, F., Hermanus, T., Madzivhandila, M., Kgagudi, P., Oosthuysen, B., Lambson, B. E., de Oliveira, T., Vermeulen, M., van der Berg, K., et al. (2021) · Nature Medicine · doi:10.1038/s41591-021-01285-x · Cited by 1,147 · see citing works
Evidence of escape of SARS-CoV-2 variant B.1.351 from natural and vaccine-induced sera
Zhou, D., Dejnirattisai, W., Supasa, P., Liu, C., Mentzer, A. J., Ginn, H. M., Zhao, Y., Duyvesteyn, H. M. E., Tuekprakhon, A., Nutalai, R., et al. (2021) · Cell · doi:10.1016/j.cell.2021.02.037 · Cited by 992 · see citing works
Sheikh, A., McMenamin, J., Taylor, B., & Robertson, C. (2021) · The Lancet · doi:10.1016/s0140-6736(21)01358-1 · Cited by 939 · see citing works
Increased transmissibility and global spread of SARS-CoV-2 variants of concern as at June 2021
Campbell, F., Archer, B. N., Laurenson‐Schafer, H., Jinnai, Y., Konings, F. A. J., Batra, N., Pavlin, B. I., Vandemaele, K., Kerkhove, M. D. V., Jombart, T., et al. (2021) · Eurosurveillance · doi:10.2807/1560-7917.es.2021.26.24.2100509 · Cited by 792 · see citing works
Reduced neutralization of SARS-CoV-2 B.1.617 by vaccine and convalescent serum
Liu, C., Ginn, H. M., Dejnirattisai, W., Supasa, P., Wang, B., Tuekprakhon, A., Nutalai, R., Zhou, D., Mentzer, A. J., Zhao, Y., et al. (2021) · Cell · doi:10.1016/j.cell.2021.06.020 · Cited by 669 · see citing works
Transmission, infectivity, and neutralization of a spike L452R SARS-CoV-2 variant
Deng, X., Garcia-Knight, M. A., Khalid, M. M., Servellita, V., Wang, C., Morris, M. K., Sotomayor-González, A., Glasner, D. R., Reyes, K. R., Gliwa, A. S., et al. (2021) · Cell · doi:10.1016/j.cell.2021.04.025 · Cited by 651 · see citing works
SARS-CoV-2 spike L452R variant evades cellular immunity and increases infectivity
Motozono, C., Toyoda, M., Zahradnik, J., Saito, A., Nasser, H., Tan, T. S., Ngare, I., Kimura, I., Uriu, K., Kosugi, Y., et al. (2021) · Cell Host & Microbe · doi:10.1016/j.chom.2021.06.006 · Cited by 586 · see citing works
Li, B., Deng, A., Li, K., Hu, Y., Li, Z., Shi, Y., Xiong, Q., Liu, Z., Guo, Q., Zou, L., et al. (2022) · Nature Communications · doi:10.1038/s41467-022-28089-y · Cited by 566 · see citing works
Neutralising antibody activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 vaccination
Wall, E. C., Wu, M., Harvey, R., Kelly, G., Warchal, S., Sawyer, C., Daniels, R., Hobson, P., Hatipoglu, E., Ngai, Y., et al. (2021) · The Lancet · doi:10.1016/s0140-6736(21)01290-3 · Cited by 491 · see citing works
Starr, T. N., Greaney, A. J., Dingens, A. S., & Bloom, J. D. (2021) · Cell Reports Medicine · doi:10.1016/j.xcrm.2021.100255 · Cited by 470 · see citing works
SARS-CoV-2 immune evasion by the B.1.427/B.1.429 variant of concern
McCallum, M., Bassi, J., De Marco, A., Chen, A., Walls, A. C., Di Iulio, J., Tortorici, M. A., Navarro, M.-J., Silacci-Fregni, C., Saliba, C., et al. (2021) · Science · doi:10.1126/science.abi7994 · Cited by 412 · cited 1× · see citing works
“In addition, this mutation can cause the vaccine-induced serum neutralizing antibody titer against the pseudovirus to decrease by 3–6 times [20,21], and the pseudovirus can escape many authorized monoclonal antibodies [21,22].”
BackgroundFisman, D. N., & Tuite, A. R. (2021) · Canadian Medical Association Journal · doi:10.1503/cmaj.211248 · Cited by 398 · see citing works
BNT162b2-elicited neutralization of B.1.617 and other SARS-CoV-2 variants
Liu, J., Liu, Y., Xia, H., Zou, J., Weaver, S. C., Swanson, K. A., Cai, H., Cutler, M., Cooper, D., Muik, A., et al. (2021) · Nature · doi:10.1038/s41586-021-03693-y · Cited by 342 · see citing works
SARS-CoV-2 501Y.V2 variants lack higher infectivity but do have immune escape
Li, Q., Nie, J., Wu, J., Zhang, L., Ding, R., Wang, H., Zhang, Y., Li, T., Liu, S., Zhang, M., et al. (2021) · Cell · doi:10.1016/j.cell.2021.02.042 · Cited by 341 · see citing works
Chia, P. Y., Ong, S. W. X., Chiew, C. J., Ang, L. W., Chavatte, J., Mak, T. M., Cui, L., Kalimuddin, S., Chia, W. N., Tan, C. W., et al. (2021) · Clinical Microbiology and Infection · doi:10.1016/j.cmi.2021.11.010 · Cited by 323 · see citing works
Li, B., Deng, A., Li, K., et al. (2021) · medRxiv · doi:10.1101/2021.07.07.21260122 · Cited by 292 · see citing works
Delta coronavirus variant: scientists brace for impact
Callaway, E. (2021) · Nature · doi:10.1038/d41586-021-01696-3 · Cited by 276 · see citing works
Hoffmann, M., Hofmann-Winkler, H., Krüger, N., Kempf, A., Nehlmeier, I., Graichen, L., Arora, P., Sidarovich, A., Moldenhauer, A.-S., Winkler, M. S., et al. (2021) · Cell Reports · doi:10.1016/j.celrep.2021.109415 · Cited by 258 · see citing works
Muecksch, F., Weisblum, Y., Barnes, C., Schmidt, F., Schaefer-Babajew, D. J., Wang, Z.-J., Lorenzi, J. C. C., Flyak, A., DeLaitsch, A. T., Huey-Tubman, K. E., et al. (2021) · Immunity · doi:10.1016/j.immuni.2021.07.008 · Cited by 256 · see citing works
Durable Humoral and Cellular Immune Responses 8 Months after Ad26.COV2.S Vaccination
Barouch, D. H., Stephenson, K. E., Sadoff, J., Yu, J., Chang, A., Gebre, M., McMahan, K., Liu, J., Chandrashekar, A., Patel, S., et al. (2021) · New England Journal of Medicine · doi:10.1056/nejmc2108829 · Cited by 237 · see citing works
Ella, R., Reddy, S., Blackwelder, W., Potdar, V., Yadav, P., Sarangi, V., Aileni, V. K., Kanungo, S., Rai, S., Reddy, P., et al. (2021) · The Lancet · doi:10.1016/s0140-6736(21)02000-6 · Cited by 217 · see citing works
Zhang, M., Xiao, J., Deng, A., Zhang, Y., Zhuang, Y., Hu, T., Li, J., Tu, H., Li, B., Zhou, Y., et al. (2021) · China CDC Weekly · doi:10.46234/ccdcw2021.148 · Cited by 210 · see citing works
Self-citationTchesnokova, V. L., Kulasekara, H. D., Larson, L., Bowers, V., Rechkina, E., Kisiela, D., Sledneva, Y., Choudhury, D., Maslova, I., Deng, K., et al. (2021) · Journal of Clinical Microbiology · doi:10.1128/jcm.00921-21 · Cited by 210 · see citing works
Wang, R., Chen, J., Gao, K., & Wei, G.-W. (2021) · Genomics · doi:10.1016/j.ygeno.2021.05.006 · Cited by 191 · see citing works
Reduced neutralisation of the Delta (B.1.617.2) SARS-CoV-2 variant of concern following vaccination
Davis, C., Logan, N. A., Tyson, G. B., Orton, R. J., Harvey, W. T., Perkins, J. S., Mollett, G., Blacow, R., Peacock, T. P., Barclay, W., et al. (2021) · PLoS Pathogens · doi:10.1371/journal.ppat.1010022 · Cited by 188 · see citing works
Alpha, Beta, Delta, Gamma: What’s important to know about SARS-CoV-2 variants of concern?
Duong, D. (2021) · Canadian Medical Association Journal · doi:10.1503/cmaj.1095949 · Cited by 178 · see citing works
Tchesnokova, V., Kulakesara, H., Larson, L., et al. (2021) · bioRxiv · doi:10.1101/2021.02.22.432189 · Cited by 154 · see citing works
Giacomo, S. D., Mercatelli, D., Rakhimov, A., & Giorgi, F. (2021) · Journal of Medical Virology · doi:10.1002/jmv.27062 · Cited by 140 · see citing works
AZD1222-induced neutralising antibody activity against SARS-CoV-2 Delta VOC
Wall, E. C., Wu, M., Harvey, R., Kelly, G. P., Warchal, S., Sawyer, C., Daniels, R. S., Adams, L., Hobson, P. S., Hatipoglu, E., et al. (2021) · The Lancet · doi:10.1016/s0140-6736(21)01462-8 · Cited by 116 · see citing works
Serum Neutralizing Activity of mRNA-1273 against SARS-CoV-2 Variants
Choi, A., Koch, M., Wu, K., Dixon, G., Oestreicher, J., Legault, H. M., Stewart-Jones, G. B. E., Colpitts, T., Pajón, R., Bennett, H., et al. (2021) · Journal of Virology · doi:10.1128/jvi.01313-21 · Cited by 109 · see citing works
Progressive Increase in Virulence of Novel SARS-CoV-2 Variants in Ontario, CanadaPreprint
Fisman, D. N., & Tuite, A. R. (2021) · medRxiv · doi:10.1101/2021.07.05.21260050 · Cited by 108 · see citing works
Saito, A., Irie, T., Suzuki, R., Maemura, T., Nasser, H., Uriu, K., Kosugi, Y., Shirakawa, K., Sadamasu, K., Kimura, I., et al. (2021) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2021.06.17.448820 · Cited by 102 · see citing works
Tada, T., Zhou, H., Dcosta, B. M., Samanovic, M. I., Mulligan, M. J., & Landau, N. R. (2021) · doi:10.1101/2021.05.14.444076 · Cited by 101 · see citing works
Pascarella, S., Ciccozzi, M., Zella, D., Bianchi, M., Benedetti, F., Benvenuto, D., Broccolo, F., Cauda, R., Caruso, A., Angeletti, S., et al. (2021) · Journal of Medical Virology · doi:10.1002/jmv.27210 · Cited by 98 · see citing works
Fratev, F. (2021) · Journal of Chemical Information and Modeling · doi:10.1021/acs.jcim.1c01242 · Cited by 95 · see citing works
Persistence of neutralizing antibodies a year after SARS‐CoV‐2 infection in humans
Haveri, A., Ekström, N., Solastie, A., Virta, C., Österlund, P., Isosaari, E., Nohynek, H., PALMU, A. A. I., & Melin, M. M. (2021) · European Journal of Immunology · doi:10.1002/eji.202149535 · Cited by 85 · see citing works
An emerging SARS-CoV-2 mutant evading cellular immunity and increasing viral infectivityPreprint
Motozono, C., Toyoda, M., Zahradník, J., Ikeda, T., Saito, A., Tan, T. S., Ngare, I., Nasser, H., Kimura, I., Uriu, K., et al. (2021) · bioRxiv · doi:10.1101/2021.04.02.438288 · Cited by 74 · see citing works
Fratev, F. (2020) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2020.12.23.424283 · Cited by 67 · see citing works
Neutralisation of ZF2001-elicited antisera to SARS-CoV-2 variants
Zhao, X., Zheng, A., Li, D., et al. (2021) · The Lancet Microbe · doi:10.1016/s2666-5247(21)00217-2 · Cited by 61 · see citing works
Reduced neutralisation of the Delta (B.1.617.2) SARS-CoV-2 variant of concern following vaccinationPreprint
Davis, C., Logan, N. A., Tyson, G. B., et al. (2021) · medRxiv · doi:10.1101/2021.06.23.21259327 · Cited by 51 · see citing works
Ella, R., Reddy, S., Blackwelder, W., Potdar, V., Yadav, P. D., Sarangi, V., Aileni, V. K., Kanungo, S., Rai, S., Reddy, P., et al. (2021) · medRxiv · doi:10.1101/2021.06.30.21259439 · Cited by 50 · see citing works
Lubinski, B., Frazier, L. E., Phan, M. V. T., Bugumbe, D., Cunningham, J. L., Tang, T., Daniel, S., Cotten, M. L., Jaimes, J. A., & Whittaker, G. R. (2021) · SSRN Electronic Journal · doi:10.1101/2021.06.30.450632 · Cited by 49 · see citing works
Ad26.COV2.S elicited neutralizing activity against Delta and other SARS-CoV-2 variants of concernPreprint
Jongeneelen, M. A. C., Kaszás, K., Veldman, D., Huizingh, J., van der Vlugt, R., Schouten, T. G., Zuijdgeest, D., Uil, T. G., Roey, G. V., Guimerà, N., et al. (2021) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2021.07.01.450707 · Cited by 45 · see citing works
Lubinski, B., Frazier, L. E., Phan, M. V. T., Bugembe, D. L., Cunningham, J. L., Tang, T., Daniel, S., Cotten, M. L., Jaimes, J. A., & Whittaker, G. R. (2022) · Microbiology Spectrum · doi:10.1128/spectrum.01514-22 · Cited by 43 · see citing works
Muecksch, F., Weisblum, Y., Barnes, C. O., Schmidt, F., Schaefer-Babajew, D., Lorenzi, J. C. C., Flyak, A. I., DeLaitsch, A. T., Huey-Tubman, K. E., Hou, S., et al. (2021) · doi:10.1101/2021.03.07.434227 · Cited by 39 · see citing works
Yadav, P. D., Sapkal, G. N., Ella, R., Sahay, R. R., Nyayanit, D. A., Patil, D. Y., Deshpande, G. R., Shete, A. M., Gupta, N., Mohan, V., et al. (2021) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2021.06.05.447177 · Cited by 39 · see citing works
Sapkal, G. N., Yadav, P. D., Sahay, R. R., Deshpande, G. R., Gupta, N., Nyayanit, D. A., Patil, D. Y., Shete, A. M., Kumar, S., Abraham, P., et al. (2021) · Journal of Travel Medicine · doi:10.1093/jtm/taab119 · Cited by 36 · see citing works
Persistence of neutralizing antibodies a year after SARS-CoV-2 infectionPreprint
Haveri, A., Ekström, N., Solastie, A., et al. (2021) · medRxiv · doi:10.1101/2021.07.13.21260426 · Cited by 15 · see citing works
Zhao, X., Zheng, A., Li, D., Zhang, R., Sun, H., Wang, Q., Gao, G. F., Han, P., & Dai, L. (2021) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2021.07.15.452504 · Cited by 10 · see citing works
Self-citationReduced neutralization of SARS-CoV-2 B.1.617 variant by inactivated and RBD-subunit vaccinePreprint
Hu, J., Wei, X., Jin, X., Peng, P., Xu, F.-L., Wu, K., Luo, F., Jin, A., Fang, L., Liu, B., et al. (2021) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2021.07.09.451732 · Cited by 9 · see citing works
Flagged first, then by citations
Research works printed but not linked: 5
- Mlcochova P, Kemp S, Dhar MS, et al. SARS-CoV-2 B.1.617.2 Delta variant emergence, replication and sensitivity to neutralising antibodies. bioRxiv. 2021. doi:10.1101/2021.05.08.443253. · DOI · Paper page
- Nasreen S, Chung H, He S, et al. Effectiveness of SARS-COV-2 vaccines against variants of concern in Ontario, Canada. medRxiv. 2021. doi:10.1101/2021.06.28.21259420. •• Real-world data from Canada indicated the efficacies of the BNT162b2, mRNA-1273 and ChAdOx1 vaccines against VOCs. · DOI
- Sapkal GN, Yadav PD, Sahay RR, et al. Neutralization of Delta variant with sera of Covishield vaccinees and SARS-COV-2 recovered vac- cinated individuals. bioRxiv. 2021. doi:10.1101/2021.07.01.450676. · DOI
- Barouch DH, Stephenson KE, Sadoff J, et al. Durable humoral and cellular immune responses following Ad26.COV2.S vaccination for SARS-COV-2. medRxiv. 2021. doi:10.1101/2021.07.05.21259918. · DOI
- Vacharathit V, Aiewsakun P, Manopwisedjaroen S, et al. SARS-CoV-2 variants of concern exhibit reduced sensitivity to live-virus neutraliza- tion in sera from CoronaVac vaccinees and naturally infected SARS-COV-2 patients. medRxiv. 2021. doi:10.1101/ 2021.07.10.21260232. · DOI
Cited by
Sorted by citations
The Lancet Commission on lessons for the future from the COVID-19 pandemic
Sachs, J. D., Karim, S. S. A., Aknin, L., Allen, J., Brosbøl, K., Colombo, F., Barron, G. C., Espinosa, M. F., Gaspar, V., Gaviria, A., et al. (2022) · The Lancet · doi:10.1016/s0140-6736(22)01585-9 · Cited by 842 · see citing works
- Authors
- Bian, L., Gao, Q., Gao, F., Wang, Q., He, Q., Wu, X., Mao, Q., Xu, M., & Liang, Z.
- Affiliations
- National Institutes for Food and Drug Control (CN)
- Corresponding author
- Liang, Zhenglun
- Venue
- Expert Review of Vaccines
- Publisher
- Informa UK Limited
- Published
- 2021-09-09
- Volume
- 20
- Issue
- 10
- Pages
- 1201-1209
- ISSN
- 1476-0584 (ISSN-L)
- 1744-8395
- PMC
- PMC8442750
- OpenAlex
- W3197480610
- Cited by
- 219
- References
- 60
- Citations by year
- 2026: 1 · 2025: 11 · 2024: 24 · 2023: 63 · 2022: 99 · 2021: 21
- FWCI
- 6.06
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Expert Review of Vaccines (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Key R&D Program of China
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Keywords
- Delta variant, vaccine efficacy, neutralizing antibodies, immune evasion, breakthrough infection, vaccination coverage, masking
- MeSH terms
- COVID-19, SARS-CoV-2, COVID-19 Vaccines, Antibodies, Viral, Hospitalization, Humans, Severity of Illness Index, Vaccination, Immune Evasion, Antibodies, Neutralizing
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
