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Tracing and analysis of 288 early SARS-CoV-2 infections outside China: A modeling study.
PLoS Med. 2020 07; 17(7):e1003193.PM

Abstract

BACKGROUND

In the early months of 2020, a novel coronavirus disease (COVID-19) spread rapidly from China across multiple countries worldwide. As of March 17, 2020, COVID-19 was officially declared a pandemic by the World Health Organization. We collected data on COVID-19 cases outside China during the early phase of the pandemic and used them to predict trends in importations and quantify the proportion of undetected imported cases.

METHODS AND FINDINGS

Two hundred and eighty-eight cases have been confirmed out of China from January 3 to February 13, 2020. We collected and synthesized all available information on these cases from official sources and media. We analyzed importations that were successfully isolated and those leading to onward transmission. We modeled their number over time, in relation to the origin of travel (Hubei province, other Chinese provinces, other countries) and interventions. We characterized the importation timeline to assess the rapidity of isolation and epidemiologically linked clusters to estimate the rate of detection. We found a rapid exponential growth of importations from Hubei, corresponding to a doubling time of 2.8 days, combined with a slower growth from the other areas. We predicted a rebound of importations from South East Asia in the successive weeks. Time from travel to detection has considerably decreased since first importation, from 14.5 ± 5.5 days on January 5, 2020, to 6 ± 3.5 days on February 1, 2020. However, we estimated 36% of detection of imported cases. This study is restricted to the early phase of the pandemic, when China was the only large epicenter and foreign countries had not discovered extensive local transmission yet. Missing information in case history was accounted for through modeling and imputation.

CONCLUSIONS

Our findings indicate that travel bans and containment strategies adopted in China were effective in reducing the exportation growth rate. However, the risk of importation was estimated to increase again from other sources in South East Asia. Surveillance and management of traveling cases represented a priority in the early phase of the epidemic. With the majority of imported cases going undetected (6 out of 10), countries experienced several undetected clusters of chains of local transmissions, fueling silent epidemics in the community. These findings become again critical to prevent second waves, now that countries have reduced their epidemic activity and progressively phase out lockdown.

Authors+Show Affiliations

INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France.Facultad de Física, Universidad de la Habana, Cuba.Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università degli Studi di Parma, Parco Area delle Scienze, Parma, Italy. INFN, Gruppo Collegato di Parma, Parco Area delle Scienze, Parma, Italy.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France. Sociology and Economics of Networks and Services lab at Orange Experience Design Lab (SENSE/XDLab) Chatillion, Paris, France.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France. Center for Biomedical Modeling, The Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, United States of America.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France.INSERM, Sorbonne Université, Pierre Louis Institute of Epidemiology and Public Health, Paris, France.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32678827

Citation

Pinotti, Francesco, et al. "Tracing and Analysis of 288 Early SARS-CoV-2 Infections Outside China: a Modeling Study." PLoS Medicine, vol. 17, no. 7, 2020, pp. e1003193.
Pinotti F, Di Domenico L, Ortega E, et al. Tracing and analysis of 288 early SARS-CoV-2 infections outside China: A modeling study. PLoS Med. 2020;17(7):e1003193.
Pinotti, F., Di Domenico, L., Ortega, E., Mancastroppa, M., Pullano, G., Valdano, E., Boëlle, P. Y., Poletto, C., & Colizza, V. (2020). Tracing and analysis of 288 early SARS-CoV-2 infections outside China: A modeling study. PLoS Medicine, 17(7), e1003193. https://doi.org/10.1371/journal.pmed.1003193
Pinotti F, et al. Tracing and Analysis of 288 Early SARS-CoV-2 Infections Outside China: a Modeling Study. PLoS Med. 2020;17(7):e1003193. PubMed PMID: 32678827.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Tracing and analysis of 288 early SARS-CoV-2 infections outside China: A modeling study. AU - Pinotti,Francesco, AU - Di Domenico,Laura, AU - Ortega,Ernesto, AU - Mancastroppa,Marco, AU - Pullano,Giulia, AU - Valdano,Eugenio, AU - Boëlle,Pierre-Yves, AU - Poletto,Chiara, AU - Colizza,Vittoria, Y1 - 2020/07/17/ PY - 2020/02/27/received PY - 2020/06/16/accepted PY - 2020/7/18/entrez PY - 2020/7/18/pubmed PY - 2020/7/28/medline SP - e1003193 EP - e1003193 JF - PLoS medicine JO - PLoS Med VL - 17 IS - 7 N2 - BACKGROUND: In the early months of 2020, a novel coronavirus disease (COVID-19) spread rapidly from China across multiple countries worldwide. As of March 17, 2020, COVID-19 was officially declared a pandemic by the World Health Organization. We collected data on COVID-19 cases outside China during the early phase of the pandemic and used them to predict trends in importations and quantify the proportion of undetected imported cases. METHODS AND FINDINGS: Two hundred and eighty-eight cases have been confirmed out of China from January 3 to February 13, 2020. We collected and synthesized all available information on these cases from official sources and media. We analyzed importations that were successfully isolated and those leading to onward transmission. We modeled their number over time, in relation to the origin of travel (Hubei province, other Chinese provinces, other countries) and interventions. We characterized the importation timeline to assess the rapidity of isolation and epidemiologically linked clusters to estimate the rate of detection. We found a rapid exponential growth of importations from Hubei, corresponding to a doubling time of 2.8 days, combined with a slower growth from the other areas. We predicted a rebound of importations from South East Asia in the successive weeks. Time from travel to detection has considerably decreased since first importation, from 14.5 ± 5.5 days on January 5, 2020, to 6 ± 3.5 days on February 1, 2020. However, we estimated 36% of detection of imported cases. This study is restricted to the early phase of the pandemic, when China was the only large epicenter and foreign countries had not discovered extensive local transmission yet. Missing information in case history was accounted for through modeling and imputation. CONCLUSIONS: Our findings indicate that travel bans and containment strategies adopted in China were effective in reducing the exportation growth rate. However, the risk of importation was estimated to increase again from other sources in South East Asia. Surveillance and management of traveling cases represented a priority in the early phase of the epidemic. With the majority of imported cases going undetected (6 out of 10), countries experienced several undetected clusters of chains of local transmissions, fueling silent epidemics in the community. These findings become again critical to prevent second waves, now that countries have reduced their epidemic activity and progressively phase out lockdown. SN - 1549-1676 UR - https://www.unboundmedicine.com/medline/citation/32678827/Tracing_and_analysis_of_288_early_SARS_CoV_2_infections_outside_China:_A_modeling_study_ L2 - https://dx.plos.org/10.1371/journal.pmed.1003193 DB - PRIME DP - Unbound Medicine ER -