Imperial College London
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ProfessorHelenWard

Faculty of Medicine, School of Public Health

Professor of Public Health
 
 
 
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Contact

 

+44 (0)20 7594 3303h.ward Website

 
 
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Location

 

311School of Public HealthWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Elliott:2021:10.1126/science.abl9551,
author = {Elliott, P and Haw, D and Wang, H and Eales, O and Walters, C and Ainslie, K and Atchison, C and Fronterre, C and Diggle, P and Page, A and Trotter, A and Prosolek, S and The, COVID-19 Genomics UK Consortium COG-UK and Ashby, D and Donnelly, C and Barclay, W and Taylor, G and Cooke, G and Ward, H and Darzi, A and Riley, S},
doi = {10.1126/science.abl9551},
journal = {Science},
pages = {1--11},
title = {Exponential growth, high prevalence of SARS-CoV-2 and vaccine effectiveness associated with Delta variant},
url = {http://dx.doi.org/10.1126/science.abl9551},
volume = {374},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - 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.
AU  - Elliott,P
AU  - Haw,D
AU  - Wang,H
AU  - Eales,O
AU  - Walters,C
AU  - Ainslie,K
AU  - Atchison,C
AU  - Fronterre,C
AU  - Diggle,P
AU  - Page,A
AU  - Trotter,A
AU  - Prosolek,S
AU  - The,COVID-19 Genomics UK Consortium COG-UK
AU  - Ashby,D
AU  - Donnelly,C
AU  - Barclay,W
AU  - Taylor,G
AU  - Cooke,G
AU  - Ward,H
AU  - Darzi,A
AU  - Riley,S
DO  - 10.1126/science.abl9551
EP  - 11
PY  - 2021///
SN  - 0036-8075
SP  - 1
TI  - Exponential growth, high prevalence of SARS-CoV-2 and vaccine effectiveness associated with Delta variant
T2  - Science
UR  - http://dx.doi.org/10.1126/science.abl9551
UR  - https://www.science.org/doi/10.1126/science.abl9551
UR  - http://hdl.handle.net/10044/1/92753
VL  - 374
ER  -
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