Imperial College London
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ProfessorSamirBhatt

Faculty of Medicine, School of Public Health

Professor of Statistics and Public Health
 
 
 
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Contact

 

+44 (0)20 7594 5029s.bhatt

 
 
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Location

 

G32ASt Mary's Research BuildingSt Mary's Campus

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Summary

 

Publications

Citation

BibTex format

@article{Laydon:2021:10.1136/bmjopen-2021-050346,
author = {Laydon, D and Mishra, S and Hinsley, W and Samartsidis, P and Flaxman, S and Gandy, A and Ferguson, N and Bhatt, S},
doi = {10.1136/bmjopen-2021-050346},
journal = {BMJ Open},
title = {Modelling the impact of the Tier system on SARS-CoV-2 transmission in the UK between the first and second national lockdowns},
url = {http://dx.doi.org/10.1136/bmjopen-2021-050346},
volume = {11},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Objective To measure the effects of the tier system on the COVID-19 pandemic in the UK between the first and second national lockdowns, before the emergence of the B.1.1.7 variant of concern.Design This is a modelling study combining estimates of real-time reproduction number Rt (derived from UK case, death and serological survey data) with publicly available data on regional non-pharmaceutical interventions. We fit a Bayesian hierarchical model with latent factors using these quantities to account for broader national trends in addition to subnational effects from tiers.Setting The UK at lower tier local authority (LTLA) level. 310 LTLAs were included in the analysis.Primary and secondary outcome measures Reduction in real-time reproduction number Rt.Results Nationally, transmission increased between July and late September, regional differences notwithstanding. Immediately prior to the introduction of the tier system, Rt averaged 1.3 (0.9–1.6) across LTLAs, but declined to an average of 1.1 (0.86–1.42) 2 weeks later. Decline in transmission was not solely attributable to tiers. Tier 1 had negligible effects. Tiers 2 and 3, respectively, reduced transmission by 6% (5%–7%) and 23% (21%–25%). 288 LTLAs (93%) would have begun to suppress their epidemics if every LTLA had gone into tier 3 by the second national lockdown, whereas only 90 (29%) did so in reality.Conclusions The relatively small effect sizes found in this analysis demonstrate that interventions at least as stringent as tier 3 are required to suppress transmission, especially considering more transmissible variants, at least until effective vaccination is widespread or much greater population immunity has amassed.
AU  - Laydon,D
AU  - Mishra,S
AU  - Hinsley,W
AU  - Samartsidis,P
AU  - Flaxman,S
AU  - Gandy,A
AU  - Ferguson,N
AU  - Bhatt,S
DO  - 10.1136/bmjopen-2021-050346
PY  - 2021///
SN  - 2044-6055
TI  - Modelling the impact of the Tier system on SARS-CoV-2 transmission in the UK between the first and second national lockdowns
T2  - BMJ Open
UR  - http://dx.doi.org/10.1136/bmjopen-2021-050346
UR  - http://hdl.handle.net/10044/1/87460
VL  - 11
ER  -
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