Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK
Open accessAbstract
The effectiveness of BNT162b2, ChAdOx1, and mRNA-1273 vaccines against new SARS-CoV-2 infections requires continuous re-evaluation, given the increasingly dominant Delta variant. We investigated the effectiveness of the vaccines in a large community-based survey of randomly selected households across the UK. We found that the effectiveness of BNT162b2 and ChAd0x1 against any infections (new PCR positives) and infections with symptoms or high viral burden is reduced with the Delta variant. A single dose of the mRNA-1273 vaccine had similar or greater effectiveness compared to a single dose of BNT162b2 or ChAdOx1. Effectiveness of two doses remains at least as great as protection afforded by prior natural infection. The dynamics of immunity following second doses differed significantly between BNT162b2 and ChAdOx1, with greater initial effectiveness against new PCR-positives but faster declines in protection against high viral burden and symptomatic infection with BNT162b2. There was no evidence that effectiveness varied by dosing interval, but protection was higher among those vaccinated following a prior infection and younger adults. With Delta, infections occurring following two vaccinations had similar peak viral burden to those in unvaccinated individuals. SARS-CoV-2 vaccination still reduces new infections, but effectiveness and attenuation of peak viral burden are reduced with Delta.
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A test-negative case-control design was used to estimate vaccine effectiveness against symptomatic Covid-19 caused by the omicron variant as compared with the delta variant in persons 18 years of age or older.
“We used a test-negative case–control design to estimate vaccine effectiveness against symptomatic Covid-19 caused by the omicron variant as compared with the delta variant in persons 18 years of age or older.”
From Effectiveness of COVID-19 vaccines against the Omicron (B.1.1.529) variant of concern (2021) · cites this paper as [17]
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Cites
Regression Modeling Strategies
Harrell, F. E. (2001) · Springer series in statistics · doi:10.1007/978-1-4757-3462-1 · Cited by 9,357 · see citing works
Harrell (2015) · Springer Series in Statistics · doi:10.1007/978-3-319-19425-7 · Cited by 6,878 · see citing works
Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant
Lopez Bernal, J., Andrews, N., Gower, C., Gallagher, E., Simmons, R., Thelwall, S., Stowe, J., Tessier, E., Groves, N., Dabrera, G., et al. (2021) · New England Journal of Medicine · doi:10.1056/nejmoa2108891 · Cited by 2,889 · see citing works
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
Waning Immunity after the BNT162b2 Vaccine in Israel
Goldberg, Y., Mandel, M., Bar-On, Y. M., Bodenheimer, O., Freedman, L., Haas, E. J., Milo, R., Alroy-Preis, S., Ash, N., & Huppert, A. (2021) · New England Journal of Medicine · doi:10.1056/nejmoa2114228 · Cited by 1,034 · see citing works
Immunological considerations for COVID-19 vaccine strategies
Jeyanathan, M., Afkhami, S., Smaill, F., Miller, M. S., Lichty, B. D., & Xing, Z. (2020) · Nature Reviews Immunology · doi:10.1038/s41577-020-00434-6 · Cited by 1,015 · 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
ChAdOx1 nCoV-19 vaccine prevents SARS-CoV-2 pneumonia in rhesus macaques
van Doremalen, N., Lambe, T., Spencer, A., Belij-Rammerstorfer, S., Purushotham, J. N., Port, J. R., Avanzato, V. A., Bushmaker, T., Flaxman, A., Ulaszewska, M., et al. (2020) · Nature · doi:10.1038/s41586-020-2608-y · Cited by 914 · see citing works
Mucosal vaccines — fortifying the frontiers
Lavelle, E. C., & Ward, R. W. (2021) · Nature reviews. Immunology · doi:10.1038/s41577-021-00583-2 · Cited by 763 · see citing works
Thompson, M. G., Burgess, J. L., Naleway, A. L., Tyner, H. L., Yoon, S. K., Meece, J., Olsho, L. E. W., Caban-Martinez, A. J., Fowlkes, A., Lutrick, K., et al. (2021) · MMWR. Morbidity and Mortality Weekly Report · doi:10.15585/mmwr.mm7013e3 · Cited by 707 · see citing works
A Single-Dose Intranasal ChAd Vaccine Protects Upper and Lower Respiratory Tracts against SARS-CoV-2
Hassan, A. O., Kafai, N. M., Dmitriev, I., Fox, J., Smith, B. K., Harvey, I. B., Chen, R. E., Winkler, E. S., Wessel, A. W., Case, J., et al. (2020) · Cell · doi:10.1016/j.cell.2020.08.026 · Cited by 568 · see citing works
BNT162b2 and mRNA-1273 COVID-19 vaccine effectiveness against the SARS-CoV-2 Delta variant in Qatar
Tang, P., Hasan, M. R., Chemaitelly, H., Yassine, H. M., Benslimane, F. M., Al Khatib, H. A., AlMukdad, S., Coyle, P., Ayoub, H. H., Al Kanaani, Z., et al. (2021) · Nature Medicine · doi:10.1038/s41591-021-01583-4 · Cited by 450 · see citing works
Chemaitelly, H., Yassine, H. M., Benslimane, F. M., Al Khatib, H. A., Tang, P., Hasan, M. R., Malek, J. A., Coyle, P., Ayoub, H. H., Al Kanaani, Z., et al. (2021) · Nature Medicine · doi:10.1038/s41591-021-01446-y · Cited by 386 · see citing works
Nasreen, S., Chung, H., He, S., Brown, K. A., Gubbay, J. B., Buchan, S. A., Fell, D. B., Austin, P. C., Schwartz, K. L., Sundaram, M. E., et al. (2022) · Nature Microbiology · doi:10.1038/s41564-021-01053-0 · Cited by 350 · see citing works
Performance characteristics of five immunoassays for SARS-CoV-2: a head-to-head benchmark comparison
Ainsworth, M. A., Andersson, M. I., Auckland, K., Baillie, J. K., Barnes, E. J., Beer, S., Beveridge, A., Bibi, S., Blackwell, L., Borak, M., et al. (2020) · The Lancet Infectious Diseases · doi:10.1016/s1473-3099(20)30634-4 · Cited by 337 · see citing works
Self-citationWei, J., Stoesser, N. E., Matthews, P. C., Ayoubkhani, D., Studley, R., Bell, I., Bell, J. I., Newton, J. N., Farrar, J., Diamond, I. D., et al. (2021) · Nature Microbiology · doi:10.1038/s41564-021-00947-3 · Cited by 331 · see citing works
Self-citationChia, 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 331 · see citing works
Impact of vaccination on new SARS-CoV-2 infections in the United Kingdom
Pritchard, E., Matthews, P. C., Stoesser, N. E., Eyre, D. W., Gethings, O., Vihta, K.-D., Jones, J. W., House, T., VanSteenhouse, H. C., Bell, I., et al. (2021) · Nature Medicine · doi:10.1038/s41591-021-01410-w · Cited by 315 · see citing works
Self-citationChung, H., He, S., Nasreen, S., Sundaram, M. E., Buchan, S. A., Wilson, S. E., Chen, B., Calzavara, A., Fell, D. B., Austin, P. C., et al. (2021) · BMJ · doi:10.1136/bmj.n1943 · Cited by 307 · see citing works
Immune correlates of protection by mRNA-1273 vaccine against SARS-CoV-2 in nonhuman primates
Corbett, K. S., Nason, M. C., Flach, B., Gagne, M., O’Connell, S., Johnston, T. S., Shah, S. N., Edara, V. V., Floyd, K., Lai, L., et al. (2021) · Science · doi:10.1126/science.abj0299 · Cited by 286 · see citing works
Correlation of SARS-CoV-2-breakthrough infections to time-from-vaccine
Mizrahi, B., Lotan, R., Kalkstein, N., Peretz, A., Perez, G., Ben-Tov, A., Chodick, G., Gazit, S., & Patalon, T. (2021) · Nature Communications · doi:10.1038/s41467-021-26672-3 · Cited by 261 · see citing works
Puranik, A., Lenehan, P. J., Silvert, E., Niesen, M. J. M., Corchado-García, J., O’Horo, J. C., Virk, A., Swift, M. D., Halamka, J. D., Badley, A. D., et al. (2021) · medRxiv · doi:10.1101/2021.08.06.21261707 · Cited by 255 · see citing works
Estimating epidemiologic dynamics from cross-sectional viral load distributions
Hay, J. A., Kennedy-Shaffer, L., Kanjilal, S., Lennon, N., Gabriel, S., Lipsitch, M., & Mina, M. (2020) · Science · doi:10.1126/science.abh0635 · Cited by 242 · see citing works
Self-citationReduced 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
Pilishvili, T., Fleming-Dutra, K. E., Farrar, J. L., Gierke, R., Mohr, N. M., Talan, D. A., Krishnadasan, A., Harland, K. K., Smithline, H. A., Hou, P. C., et al. (2021) · MMWR Morbidity and Mortality Weekly Report · doi:10.15585/mmwr.mm7020e2 · Cited by 185 · see citing works
Self-citationShrotri, M., Krutikov, M., Palmer, T., Giddings, R., Azmi, B., Subbarao, S., Fuller, C., Irwin-Singer, A., Davies, D., Tut, G., et al. (2021) · The Lancet Infectious Diseases · doi:10.1016/s1473-3099(21)00289-9 · Cited by 180 · see citing works
Pouwels, K. B., House, T., Pritchard, E., Robotham, J. V., Birrell, P., Gelman, A., Vihta, K.-D., Bowers, N., Boreham, I., Thomas, H., et al. (2020) · The Lancet Public Health · doi:10.1016/s2468-2667(20)30282-6 · Cited by 177 · see citing works
Self-citationElapsed time since BNT162b2 vaccine and risk of SARS-CoV-2 infection: test negative design study
Israel, A., Merzon, E., Schäffer, A. A., Shenhar, Y., Green, I., Golan-Cohen, A., Ruppin, E., Magen, E., & Vinker, S. (2021) · BMJ · doi:10.1136/bmj-2021-067873 · Cited by 170 · see citing works
Shedding of infectious SARS-CoV-2 despite vaccination
Riemersma, K. K., Haddock, L. A., Wilson, N. A., Minor, N. R., Eickhoff, J. C., Grogan, B., Kita-Yarbro, A., Halfmann, P., Segaloff, H. E., Kocharian, A., et al. (2022) · PLoS Pathogens · doi:10.1371/journal.ppat.1010876 · Cited by 161 · see citing works
Lee, L. Y. W., Rozmanowski, S., Pang, M., Charlett, A., Anderson, C. S., Hughes, G. J., Barnard, M., Peto, L., Vipond, R., Sienkiewicz, A., et al. (2021) · Clinical Infectious Diseases · doi:10.1093/cid/ciab421 · Cited by 141 · see citing works
Self-citationHarder, T., Koch, J., Vygen-Bonnet, S., Külper‐Schiek, W., Pilic, A., Reda, S. A., Scholz, S. M., & Wichmann, O. (2021) · Eurosurveillance · doi:10.2807/1560-7917.es.2021.26.28.2100563 · Cited by 120 · see citing works
Walker, A. S., Pritchard, E., House, T., Robotham, J. V., Birrell, P., Bell, I., Bell, J. I., Newton, J. N., Farrar, J., Diamond, I. D., et al. (2021) · eLife · doi:10.7554/elife.64683 · Cited by 116 · see citing works
Self-citationSARS-CoV-2 Vaccine Effectiveness in a High-Risk National Population in a Real-World Setting
Butt, A. A., Omer, S. B., Peng, Y., Shaikh, O. S., & Mayr, F. (2021) · Annals of Internal Medicine · doi:10.7326/m21-1577 · Cited by 108 · see citing works
Theoretical Framework for Retrospective Studies of the Effectiveness of SARS-CoV-2 Vaccines
Lewnard, J. A., Patel, M. M., Jewell, N. P., Verani, J. R., Kobayashi, M., Tenforde, M. W., Dean, N. E., Cowling, B. J., & Lopman, B. A. (2021) · Epidemiology · doi:10.1097/ede.0000000000001366 · Cited by 103 · see citing works
Charmet, T., Schaeffer, L., Grant, R., Galmiche, S., Chény, O., Von Platen, C., Maurizot, A., Rogoff, A., Omar, F., David, C., et al. (2021) · The Lancet Regional Health - Europe · doi:10.1016/j.lanepe.2021.100171 · Cited by 80 · see citing works
Vaccine effectiveness studies in the field
Evans, S. J. W., & Jewell, N. P. (2021) · New England Journal of Medicine · doi:10.1056/nejme2110605 · Cited by 65 · see citing works
Noori, M., Nejadghaderi, S. A., Arshi, S., Carson‐Chahhoud, K., Ansarin, K., Kolahi, A., & Safiri, S. (2021) · Reviews in Medical Virology · doi:10.1002/rmv.2277 · Cited by 64 · see citing works
Shrotri, M., Krutikov, M., Palmer, T., et al. (2021) · medRxiv · doi:10.1101/2021.03.26.21254391 · Cited by 52 · 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
Corbett, K. S., Nason, M. C., Flach, B., Gagne, M., O’ Connell, S., Johnston, T. S., Shah, S. N., Edara, V. V., Floyd, K., Lai, L., et al. (2021) · doi:10.1101/2021.04.20.440647 · Cited by 43 · see citing works
Imai, N., Hogan, A. B., Williams, L. R., Cori, A., Mangal, T. D., Winskill, P., Whittles, L. K., Watson, O. J., Knock, E., Baguelin, M., et al. (2021) · Wellcome Open Research · doi:10.12688/wellcomeopenres.16992.1 · Cited by 21 · see citing works
Flagged first, then by citations
Research works printed but not linked: 3
- [11]Israel, A. et al. Elapsed time since BNT162b2 vaccine and risk of SARSCoV-2 infection in a large cohort. Preprint at https://www.medrxiv.org/content/10.1101/2021.08.03.21261496v1 (2021). PMC9083235 34819275 · DOI
- [14]Nasreen, S. et al. Effectiveness of COVID-19 vaccines against variants of concern in Ontario, Canada. Preprint at https://www.medrxiv.org/content/10.1101/2021.06.28.21259420v2 (2021). · DOI
- [25]Mlcochova, P. et al. SARS-CoV-2 B.1.617.2 Delta variant replication, sensitivity to neutralising antibodies and vaccine breakthrough. Preprint at https://www.biorxiv.org/content/biorxiv/early/2021/06/28/2021.05.08.443253.full.pdf (2021).
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Andrews, N., Stowe, J., Kirsebom, F., Toffa, S., Rickeard, T., Gallagher, E., Gower, C., Kall, M., Groves, N., O’Connell, A.-M., et al. (2021) · doi:10.1101/2021.12.14.21267615 · Cited by 2,420 · see citing works
Barda, N., Dagan, N., Cohen, C., Hernán, M. A., Lipsitch, M., Kohane, I. S., Reis, B. Y., & Balicer, R. D. (2021) · The Lancet · doi:10.1016/s0140-6736(21)02249-2 · Cited by 860 · see citing works
Andrews, N., Stowe, J., Kirsebom, F., Toffa, S., Sachdeva, R., Gower, C., Ramsay, M., & Lopez Bernal, J. (2022) · Nature Medicine · doi:10.1038/s41591-022-01699-1 · Cited by 453 · see citing works
Bruxvoort, K. J., Sy, L. S., Qian, L., Ackerson, B. K., Luo, Y., Lee, G. S., Tian, Y., Florea, A., Aragones, M., Tubert, J. E., et al. (2021) · BMJ · doi:10.1136/bmj-2021-068848 · Cited by 230 · see citing works
Gram, M. A., Emborg, H.-D., Schelde, A. B., Friis, N. U., Nielsen, K. F., Moustsen-Helms, I. R., Legarth, R., Lam, J. U. H., Chaine, M., Malik, A. Z., et al. (2022) · PLOS Medicine · doi:10.1371/journal.pmed.1003992 · Cited by 146 · see citing works
Kent, S. J., Khoury, D. S., Reynaldi, A., Juno, J. A., Wheatley, A. K., Stadler, E., John Wherry, E., Triccas, J., Sasson, S. C., Cromer, D., et al. (2022) · Nature Reviews Immunology · doi:10.1038/s41577-022-00716-1 · Cited by 139 · see citing works
Skowronski, D. M., Febriani, Y., Ouakki, M., Setayeshgar, S., El Adam, S., Zou, M., Talbot, D., Prystajecky, N., Tyson, J. R., Gilca, R., et al. (2022) · Clinical Infectious Diseases · doi:10.1093/cid/ciac290 · Cited by 155 · see citing works
Katikireddi, S. V., Cerqueira-Silva, T., Vasileiou, E., Robertson, C., Amele, S., Pan, J., Taylor, B., Boaventura, V., Werneck, G. L., Flores-Ortiz, R., et al. (2022) · The Lancet · doi:10.1016/s0140-6736(21)02754-9 · Cited by 124 · see citing works
Bounding the levels of transmissibility & immune evasion of the Omicron variant in South Africa
Pearson, C. A. B., Silal, S. P., Li, M. W. Z., Dushoff, J., Bolker, B. M., Abbott, S., van Schalkwyk, C., Davies, N. G., Barnard, R. C., Edmunds, W. J., et al. (2021) · doi:10.1101/2021.12.19.21268038 · Cited by 44 · see citing works
- Authors
- Pouwels, K. B., Pritchard, E., Matthews, P. C., Stoesser, N., Eyre, D. W., Vihta, K.-D., House, T., Hay, J., Bell, J. I., Newton, J. N., Farrar, J., Crook, D., Cook, D., Rourke, E., Studley, R., Peto, T., Diamond, I., Walker, A. S., & the COVID-19 Infection Survey Team
- Affiliations
- National Institute for Health and Care Research (GB)
- John Radcliffe Hospital (GB)
- University of Manchester (GB)
- University of Glasgow (GB)
- University of Oxford (GB)
- Public Health England (GB)
- Wellcome Trust (GB)
- Office for National Statistics (GB)
- Corresponding author
- Pouwels, Koen B.
- ORCID
- Venue
- Nature Medicine
- Publisher
- openRxiv
- Published
- 2021-08-24
- Volume
- 27
- Issue
- 12
- Pages
- 2127-2135
- ISSN
- 1078-8956 (ISSN-L)
- PMC
- PMC8674129
- OpenAlex
- W3206181818
- Cited by
- 543
- References
- 44
- Citations by year
- 2026: 4 · 2025: 18 · 2024: 49 · 2023: 90 · 2022: 289 · 2021: 93
- FWCI
- 41.33
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- cc-by
- Locations
- Nature Medicine (publishedVersion, cc-by)
- medRxiv (acceptedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- ENLIGHTEN (Jurnal Bimbingan dan Konseling Islam) (acceptedVersion, cc-by-sa)
- UCL Discovery (University College London) (submittedVersion)
- Funders
- Wellcome Trust (110,110z/15/Z, /Z/15/Z, 110110, NIHR200915)
- Scottish Government
- Llywodraeth Cymru
- National Institute for Health Research Health Protection Research Unit (NIHR200915)
- National Institute for Health and Care Research (NF-SI-0508-10279, NIHR200239, COVID-19, NIHR200915)
- Department of Health and Social Care (COVID-19)
- University of Oxford (NIHR200915)
- Public Health England (NIHR200915)
- Oxford University Hospitals NHS Foundation Trust
- Huo Family Foundation
- Medical Research Council (MC_UU_12023/22, NIHR200915, 110110/Z/15/Z, MC_UU_12023, COVID-19)
- Engineering and Physical Sciences Research Council (EP/V027468/1)
- NIHR Oxford Biomedical Research Centre (NIHR200915)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Keywords
- SARS-CoV-2, Delta variant, BNT162b2, ChAdOx1 nCoV-19 vaccine, vaccine effectiveness, viral load, breakthrough infection, Alpha variant, waning immunity, dosing interval, household surveys, COVID-19 pandemic
- MeSH terms
- COVID-19, SARS-CoV-2, Vaccine Efficacy, BNT162 Vaccine, ChAdOx1 nCoV-19, Adolescent, Adult, Antibodies, Viral, United Kingdom, Humans, Middle Aged, Vaccination, Polymerase Chain Reaction, Viral Load, Young Adult, Antibodies, Neutralizing
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