@article{444fedd1906749b58654d0d999f41f9e,
title = "Exponential growth, high prevalence of SARS-CoV-2, and vaccine effectiveness associated with the Delta variant",
abstract = "SARS-CoV-2 infections were rising during early summer 2021 in many countries associated with the Delta variant. We assessed RT-PCR swab-positivity in the REal-time Assessment of Community Transmission-1 (REACT-1) study in England. We observed sustained exponential growth with average doubling time (June-July 2021) of 25 days driven by complete replacement of Alpha variant by Delta, and by high prevalence at younger less-vaccinated ages. Unvaccinated people were three times more likely than double-vaccinated people to test positive. However, after adjusting for age and other variables, vaccine effectiveness for double-vaccinated people was estimated at between ~50% and ~60% during this period in England. Increased social mixing in the presence of Delta had the potential to generate sustained growth in infections, even at high levels of vaccination.",
keywords = "Adolescent, Adult, Age Factors, Aged, COVID-19 Nucleic Acid Testing, COVID-19 Vaccines/administration & dosage, COVID-19/diagnosis, Child, Child, Preschool, England/epidemiology, Ethnicity, Family Characteristics, Female, Hospitalization, Humans, Male, Middle Aged, Prevalence, SARS-CoV-2, Self Report, Socioeconomic Factors, Vaccination Coverage, Vaccine Efficacy, Young Adult",
author = "Paul Elliott and David Haw and Haowei Wang and Oliver Eales and Walters, {Caroline E.} and Ainslie, {Kylie E. C.} and Christina Atchison and Claudio Fronterre and Diggle, {Peter J.} and Page, {Andrew J} and Trotter, {Alexander J.} and Prosolek, {Sophie J.} and {The COVID-19 Genomics UK (COG-UK) Consortium} and Deborah Ashby and Donnelly, {Christl A.} and Wendy Barclay and Graham Taylor and Graham Cooke and Helen Ward and Ara Darzi and Steven Riley and Robson, {Samuel C} and Loman, {Nicholas J.} and Connor, {Thomas R.} and Tanya Golubchik and {Martinez Nunez}, {Rocio T} and Catherine Ludden and Sally Corden and Ian Johnston and David Bonsall and Smith, {Colin P.} and Giselda Bucca and Torok, {M Estee} and Kordo Saeed and Prieto, {Jacqui A} and Jackson, {David K} and Hamilton, {William L} and Snell, {Luke B} and Catherine Moore and Harrison, {Ewan M.} and Williams, {Rachel J} and Hannah Jones and Hartley, {John A} and Chris Williams and Smith, {Darren L} and Matthew Bashton and Andrew Nelson and Young, {Gregory R} and McCann, {Clare M} and Yew, {Wen C}",
note = "Matthew Bashton, Darren L. Smith, Gregory R. Young, Clare McCann, Andrew Nelson and Wen Chyin Yew are members of the COVID-19 Genomics UK (COG-UK) Consortium. Funding information: The study was funded by the Department of Health and Social Care in England. Sequencing was provided through funding from the COVID-19 Genomics UK (COG-UK) Consortium. P.E. is Director of the Medical Research Council (MRC) Centre for Environment and Health (MR/L01341X/1, MR/S019669/1). P.E. acknowledges support from Health Data Research UK (HDR UK); the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre; NIHR Health Protection Research Units (HPRUs) in Chemical and Radiation Threats and Hazards, and Environmental Exposures and Health; the British Heart Foundation Centre for Research Excellence at Imperial College London (RE/18/4/34215); and the UK Dementia Research Institute at Imperial (MC_PC_17114). S.R., C.A.D. acknowledge support: MRC Centre for Global Infectious Disease Analysis, NIHR HPRU in Modelling and Health Economics, Wellcome Trust (200861/Z/16/Z, 200187/Z/15/Z), and Centres for Disease Control and Prevention (US, U01CK0005-01-02). G.C. is supported by an NIHR Professorship. H.War. acknowledges support from an NIHR Senior Investigator Award and the Wellcome Trust (205456/Z/16/Z). We thank The Huo Family Foundation for their support of our work on COVID-19. Quadram authors gratefully acknowledge the support of the Biotechnology and Biological Sciences Research Council (BBSRC); their research was funded by the BBSRC Institute Strategic Programme Microbes in the Food Chain BB/R012504/1 and its constituent project BBS/E/F/000PR10352. We thank members of the COVID-19 Genomics Consortium UK (COG-UK) for their contributions to generating the genomic data used in this study. COG-UK is supported by funding from the MRC, part of UK Research & Innovation (UKRI), NIHR and Genome Research Limited, operating as the Wellcome Sanger Institute.",
year = "2021",
month = dec,
day = "17",
doi = "10.1126/science.abl9551",
language = "English",
volume = "374",
journal = "Science",
issn = "0036-8075",
publisher = "American Association for the Advancement of Science",
number = "6574",
}