Imperial College London
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ProfessorGrahamCooke

Faculty of Medicine, Department of Infectious Disease

Vice Dean (Research); Professor of Infectious Diseases
 
 
 
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Contact

 

g.cooke

 
 
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Location

 

Infectious Diseases SectionMedical SchoolSt Mary's Campus

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Summary

 

Publications

Citation

BibTex format

@unpublished{Elliott:2021,
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 COG-UK, TCGUKC and Ashby, D and Donnelly, C and Barclay, W and Cooke, G and Ward, H and Darzi, A and Riley, S},
title = {REACT-1 round 13 final report: exponential growth, high prevalence of SARS-CoV-2 and vaccine effectiveness associated with Delta variant in England during May to July 2021},
url = {http://hdl.handle.net/10044/1/90800},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - UNPB
AB  - BackgroundThe prevalence of SARS-CoV-2 infection continues to drive rates of illness andhospitalisations despite high levels of vaccination, with the proportion of cases caused by theDelta lineage increasing in many populations. As vaccination programs roll out globally andsocial distancing is relaxed, future SARS-CoV-2 trends are uncertain.MethodsWe analysed prevalence trends and their drivers using reverse transcription-polymerasechain reaction (RT-PCR) swab-positivity data from round 12 (between 20 May and 7 June2021) and round 13 (between 24 June and 12 July 2021) of the REal-time Assessment ofCommunity Transmission-1 (REACT-1) study, with swabs sent to non-overlapping randomsamples of the population ages 5 years and over in England.ResultsWe observed sustained exponential growth with an average doubling time in round 13 of 25days (lower Credible Interval of 15 days) and an increase in average prevalence from 0.15%(0.12%, 0.18%) in round 12 to 0.63% (0.57%, 0.18%) in round 13. The rapid growth acrossand within rounds appears to have been driven by complete replacement of Alpha variant byDelta, and by the high prevalence in younger less-vaccinated age groups, with a nine-foldincrease between rounds 12 and 13 among those aged 13 to 17 years. Prevalence amongthose who reported being unvaccinated was three-fold higher than those who reported beingfully vaccinated. However, in round 13, 44% of infections occurred in fully vaccinatedindividuals, reflecting imperfect vaccine effectiveness against infection despite high overalllevels of vaccination. Using self-reported vaccination status, we estimated adjusted vaccineeffectiveness against infection in round 13 of 49% (22%, 67%) among participants aged 18to 64 years, which rose to 58% (33%, 73%) when considering only strong positives (Cyclethreshold [Ct] values < 27); also, we estimated adjusted vaccine effectiveness againstsymptomatic infection of 59% (23%, 78%), with any one of three common COVID-19symptoms reported
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  - COG-UK,TCGUKC
AU  - Ashby,D
AU  - Donnelly,C
AU  - Barclay,W
AU  - Cooke,G
AU  - Ward,H
AU  - Darzi,A
AU  - Riley,S
PY  - 2021///
TI  - REACT-1 round 13 final report: exponential growth, high prevalence of SARS-CoV-2 and vaccine effectiveness associated with Delta variant in England during May to July 2021
UR  - http://hdl.handle.net/10044/1/90800
ER  -
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