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Quantifying the impact of physical distance measures on the transmission of COVID-19 in the UK.
BMC Med. 2020 05 07; 18(1):124.BM

Abstract

BACKGROUND

To mitigate and slow the spread of COVID-19, many countries have adopted unprecedented physical distancing policies, including the UK. We evaluate whether these measures might be sufficient to control the epidemic by estimating their impact on the reproduction number (R0, the average number of secondary cases generated per case).

METHODS

We asked a representative sample of UK adults about their contact patterns on the previous day. The questionnaire was conducted online via email recruitment and documents the age and location of contacts and a measure of their intimacy (whether physical contact was made or not). In addition, we asked about adherence to different physical distancing measures. The first surveys were sent on Tuesday, 24 March, 1 day after a "lockdown" was implemented across the UK. We compared measured contact patterns during the "lockdown" to patterns of social contact made during a non-epidemic period. By comparing these, we estimated the change in reproduction number as a consequence of the physical distancing measures imposed. We used a meta-analysis of published estimates to inform our estimates of the reproduction number before interventions were put in place.

RESULTS

We found a 74% reduction in the average daily number of contacts observed per participant (from 10.8 to 2.8). This would be sufficient to reduce R0 from 2.6 prior to lockdown to 0.62 (95% confidence interval [CI] 0.37-0.89) after the lockdown, based on all types of contact and 0.37 (95% CI = 0.22-0.53) for physical (skin to skin) contacts only.

CONCLUSIONS

The physical distancing measures adopted by the UK public have substantially reduced contact levels and will likely lead to a substantial impact and a decline in cases in the coming weeks. However, this projected decline in incidence will not occur immediately as there are significant delays between infection, the onset of symptomatic disease, and hospitalisation, as well as further delays to these events being reported. Tracking behavioural change can give a more rapid assessment of the impact of physical distancing measures than routine epidemiological surveillance.

Authors+Show Affiliations

Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. Christopher.Jarvis@lshtm.ac.uk.Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.No affiliation info availableCentre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.Department of Psychological Medicine, King's College London, Denmark Hill, London, UK.Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32375776

Citation

Jarvis, Christopher I., et al. "Quantifying the Impact of Physical Distance Measures On the Transmission of COVID-19 in the UK." BMC Medicine, vol. 18, no. 1, 2020, p. 124.
Jarvis CI, Van Zandvoort K, Gimma A, et al. Quantifying the impact of physical distance measures on the transmission of COVID-19 in the UK. BMC Med. 2020;18(1):124.
Jarvis, C. I., Van Zandvoort, K., Gimma, A., Prem, K., Klepac, P., Rubin, G. J., & Edmunds, W. J. (2020). Quantifying the impact of physical distance measures on the transmission of COVID-19 in the UK. BMC Medicine, 18(1), 124. https://doi.org/10.1186/s12916-020-01597-8
Jarvis CI, et al. Quantifying the Impact of Physical Distance Measures On the Transmission of COVID-19 in the UK. BMC Med. 2020 05 7;18(1):124. PubMed PMID: 32375776.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Quantifying the impact of physical distance measures on the transmission of COVID-19 in the UK. AU - Jarvis,Christopher I, AU - Van Zandvoort,Kevin, AU - Gimma,Amy, AU - Prem,Kiesha, AU - ,, AU - Klepac,Petra, AU - Rubin,G James, AU - Edmunds,W John, Y1 - 2020/05/07/ PY - 2020/04/03/received PY - 2020/04/17/accepted PY - 2020/5/8/entrez PY - 2020/5/8/pubmed PY - 2020/5/12/medline KW - COVID-19 KW - Contact survey KW - Disease outbreak KW - Pandemic KW - Reproduction number KW - nCov SP - 124 EP - 124 JF - BMC medicine JO - BMC Med VL - 18 IS - 1 N2 - BACKGROUND: To mitigate and slow the spread of COVID-19, many countries have adopted unprecedented physical distancing policies, including the UK. We evaluate whether these measures might be sufficient to control the epidemic by estimating their impact on the reproduction number (R0, the average number of secondary cases generated per case). METHODS: We asked a representative sample of UK adults about their contact patterns on the previous day. The questionnaire was conducted online via email recruitment and documents the age and location of contacts and a measure of their intimacy (whether physical contact was made or not). In addition, we asked about adherence to different physical distancing measures. The first surveys were sent on Tuesday, 24 March, 1 day after a "lockdown" was implemented across the UK. We compared measured contact patterns during the "lockdown" to patterns of social contact made during a non-epidemic period. By comparing these, we estimated the change in reproduction number as a consequence of the physical distancing measures imposed. We used a meta-analysis of published estimates to inform our estimates of the reproduction number before interventions were put in place. RESULTS: We found a 74% reduction in the average daily number of contacts observed per participant (from 10.8 to 2.8). This would be sufficient to reduce R0 from 2.6 prior to lockdown to 0.62 (95% confidence interval [CI] 0.37-0.89) after the lockdown, based on all types of contact and 0.37 (95% CI = 0.22-0.53) for physical (skin to skin) contacts only. CONCLUSIONS: The physical distancing measures adopted by the UK public have substantially reduced contact levels and will likely lead to a substantial impact and a decline in cases in the coming weeks. However, this projected decline in incidence will not occur immediately as there are significant delays between infection, the onset of symptomatic disease, and hospitalisation, as well as further delays to these events being reported. Tracking behavioural change can give a more rapid assessment of the impact of physical distancing measures than routine epidemiological surveillance. SN - 1741-7015 UR - https://www.unboundmedicine.com/medline/citation/32375776/Quantifying_the_impact_of_physical_distance_measures_on_the_transmission_of_COVID_19_in_the_UK_ DB - PRIME DP - Unbound Medicine ER -