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Ruoran Li

Bio: Ruoran Li is an academic researcher from Harvard University. The author has contributed to research in topics: Population & Survival analysis. The author has an hindex of 15, co-authored 20 publications receiving 2300 citations. Previous affiliations of Ruoran Li include University of Cambridge & University of London.

Papers
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Journal ArticleDOI
01 May 2020-Science
TL;DR: Real-time mobility data from Wuhan and detailed case data including travel history are used to elucidate the role of case importation in transmission in cities across China and to ascertain the impact of control measures.
Abstract: The ongoing coronavirus disease 2019 (COVID-19) outbreak expanded rapidly throughout China. Major behavioral, clinical, and state interventions were undertaken to mitigate the epidemic and prevent the persistence of the virus in human populations in China and worldwide. It remains unclear how these unprecedented interventions, including travel restrictions, affected COVID-19 spread in China. We used real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation in transmission in cities across China and to ascertain the impact of control measures. Early on, the spatial distribution of COVID-19 cases in China was explained well by human mobility data. After the implementation of control measures, this correlation dropped and growth rates became negative in most locations, although shifts in the demographics of reported cases were still indicative of local chains of transmission outside of Wuhan. This study shows that the drastic control measures implemented in China substantially mitigated the spread of COVID-19.

2,362 citations

Journal ArticleDOI
TL;DR: A stochastic branching model fits to reported parameters for the dynamics of SARS-CoV-2 highlights the urgent need for more data on the serial interval and the extent of presymptomatic transmission to make data-driven policy decisions regarding the cost–benefit comparisons of individual quarantine versus active monitoring.
Abstract: Summary Background Voluntary individual quarantine and voluntary active monitoring of contacts are core disease control strategies for emerging infectious diseases such as COVID-19. Given the impact of quarantine on resources and individual liberty, it is vital to assess under what conditions individual quarantine can more effectively control COVID-19 than active monitoring. As an epidemic grows, it is also important to consider when these interventions are no longer feasible and broader mitigation measures must be implemented. Methods To estimate the comparative efficacy of individual quarantine and active monitoring of contacts to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we fit a stochastic branching model to reported parameters for the dynamics of the disease. Specifically, we fit a model to the incubation period distribution (mean 5·2 days) and to two estimates of the serial interval distribution: a shorter one with a mean serial interval of 4·8 days and a longer one with a mean of 7·5 days. To assess variable resource settings, we considered two feasibility settings: a high-feasibility setting with 90% of contacts traced, a half-day average delay in tracing and symptom recognition, and 90% effective isolation; and a low-feasibility setting with 50% of contacts traced, a 2-day average delay, and 50% effective isolation. Findings Model fitting by sequential Monte Carlo resulted in a mean time of infectiousness onset before symptom onset of 0·77 days (95% CI −1·98 to 0·29) for the shorter serial interval, and for the longer serial interval it resulted in a mean time of infectiousness onset after symptom onset of 0·51 days (95% CI −0·77 to 1·50). Individual quarantine in high-feasibility settings, where at least 75% of infected contacts are individually quarantined, contains an outbreak of SARS-CoV-2 with a short serial interval (4·8 days) 84% of the time. However, in settings where the outbreak continues to grow (eg, low-feasibility settings), so too will the burden of the number of contacts traced for active monitoring or quarantine, particularly uninfected contacts (who never develop symptoms). When resources are prioritised for scalable interventions such as physical distancing, we show active monitoring or individual quarantine of high-risk contacts can contribute synergistically to mitigation efforts. Even under the shorter serial interval, if physical distancing reduces the reproductive number to 1·25, active monitoring of 50% of contacts can result in overall outbreak control (ie, effective reproductive number Interpretation Our model highlights the urgent need for more data on the serial interval and the extent of presymptomatic transmission to make data-driven policy decisions regarding the cost–benefit comparisons of individual quarantine versus active monitoring of contacts. To the extent that these interventions can be implemented, they can help mitigate the spread of SARS-CoV-2. Funding National Institute of General Medical Sciences, National Institutes of Health.

178 citations

Posted ContentDOI
06 Mar 2020-medRxiv
TL;DR: This study uses real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation on transmission in cities across China and ascertain the impact of control measures.
Abstract: The ongoing COVID-19 outbreak has expanded rapidly throughout China. Major behavioral, clinical, and state interventions are underway currently to mitigate the epidemic and prevent the persistence of the virus in human populations in China and worldwide. It remains unclear how these unprecedented interventions, including travel restrictions, have affected COVID-19 spread in China. We use real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation on transmission in cities across China and ascertain the impact of control measures. Early on, the spatial distribution of COVID-19 cases in China was well explained by human mobility data. Following the implementation of control measures, this correlation dropped and growth rates became negative in most locations, although shifts in the demographics of reported cases are still indicative of local chains of transmission outside Wuhan. This study shows that the drastic control measures implemented in China have substantially mitigated the spread of COVID-19.

152 citations

Journal ArticleDOI
TL;DR: The 21 % increase in penile cancer incidence in England since the 1970s may be explained by changes in sexual practice, greater exposure to sexually transmitted oncogenic human papilloma viruses, and decreasing rates of childhood circumcision.
Abstract: Few population-based studies exist of long-term trends in penile cancer. We report incidence and mortality trends in England over the 31 years 1979–2009 and survival trends over the 40 years 1971–2010. We calculated annual incidence and mortality rates per 100,000 by age and calendar period. We estimated incidence and mortality rate ratios for cohorts born since 1890, and one- and five-year relative survival (%) by age and deprivation category. A total of 9,690 men were diagnosed with penile cancer during 1979–2009. Age-standardized incidence rates increased by 21 %, from 1.10 to 1.33 per 100,000. Mortality rates fell by 20 % after 1994, from 0.39 to 0.31 per 100,000. Survival analyses included 11,478 men diagnosed during 1971–2010. Five-year relative survival increased from 61.4 to 70.2 %. Five-year survival for men diagnosed 2006–2010 was 77 % for men aged under 60 years and 53 % for men aged 80–99 years. The 8 % difference in five-year survival (66–74 %) between men in the most affluent and most deprived groups was not statistically significant. The 21 % increase in penile cancer incidence in England since the 1970s may be explained by changes in sexual practice, greater exposure to sexually transmitted oncogenic human papilloma viruses, and decreasing rates of childhood circumcision. Improvement in survival is likely due to advances in diagnostic, staging and surgical techniques. There is a need for public health education and potential preventative strategies to address the increasing incidence.

93 citations

Journal ArticleDOI
01 May 2020
TL;DR: It is suggested that strict disease control strategies should be implemented early to mitigate the demand for inpatient and intensive care unit beds during a coronavirus disease 2019 outbreak.
Abstract: Importance Sustained spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has happened in major US cities. Capacity needs in cities in China could inform the planning of local health care resources. Objectives To describe and compare the intensive care unit (ICU) and inpatient bed needs for patients with coronavirus disease 2019 (COVID-19) in 2 cities in China to estimate the peak ICU bed needs in US cities if an outbreak equivalent to that in Wuhan occurs. Design, Setting, and Participants This comparative effectiveness study analyzed the confirmed cases of COVID-19 in Wuhan and Guangzhou, China, from January 10 to February 29, 2020. Exposures Timing of disease control measures relative to timing of SARS-CoV-2 community spread. Main Outcomes and Measures Number of critical and severe patient–days and peak number of patients with critical and severe illness during the study period. Results In Wuhan, strict disease control measures were implemented 6 weeks after sustained local transmission of SARS-CoV-2. Between January 10 and February 29, 2020, patients with COVID-19 accounted for a median (interquartile range) of 429 (25-1143) patients in the ICU and 1521 (111-7202) inpatients with serious illness each day. During the epidemic peak, 19 425 patients (24.5 per 10 000 adults) were hospitalized, 9689 (12.2 per 10 000 adults) were considered in serious condition, and 2087 (2.6 per 10 000 adults) needed critical care per day. In Guangzhou, strict disease control measures were implemented within 1 week of case importation. Between January 24 and February 29, COVID-19 accounted for a median (interquartile range) of 9 (7-12) patients in the ICU and 17 (15-26) inpatients with serious illness each day. During the epidemic peak, 15 patients were in critical condition and 38 were classified as having serious illness. The projected number of prevalent critically ill patients at the peak of a Wuhan-like outbreak in US cities was estimated to range from 2.2 to 4.4 per 10 000 adults, depending on differences in age distribution and comorbidity (ie, hypertension) prevalence. Conclusions and Relevance Even after the lockdown of Wuhan on January 23, the number of patients with serious COVID-19 illness continued to rise, exceeding local hospitalization and ICU capacities for at least a month. Plans are urgently needed to mitigate the consequences of COVID-19 outbreaks on the local health care systems in US cities.

86 citations


Cited by
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Journal ArticleDOI
01 May 2020-Science
TL;DR: Real-time mobility data from Wuhan and detailed case data including travel history are used to elucidate the role of case importation in transmission in cities across China and to ascertain the impact of control measures.
Abstract: The ongoing coronavirus disease 2019 (COVID-19) outbreak expanded rapidly throughout China. Major behavioral, clinical, and state interventions were undertaken to mitigate the epidemic and prevent the persistence of the virus in human populations in China and worldwide. It remains unclear how these unprecedented interventions, including travel restrictions, affected COVID-19 spread in China. We used real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation in transmission in cities across China and to ascertain the impact of control measures. Early on, the spatial distribution of COVID-19 cases in China was explained well by human mobility data. After the implementation of control measures, this correlation dropped and growth rates became negative in most locations, although shifts in the demographics of reported cases were still indicative of local chains of transmission outside of Wuhan. This study shows that the drastic control measures implemented in China substantially mitigated the spread of COVID-19.

2,362 citations

Journal ArticleDOI
14 Apr 2020-Science
TL;DR: Using existing data to build a deterministic model of multiyear interactions between existing coronaviruses, with a focus on the United States, is used to project the potential epidemic dynamics and pressures on critical care capacity over the next 5 years and projected that recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave.
Abstract: It is urgent to understand the future of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) transmission. We used estimates of seasonality, immunity, and cross-immunity for human coronavirus OC43 (HCoV-OC43) and HCoV-HKU1 using time-series data from the United States to inform a model of SARS-CoV-2 transmission. We projected that recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave. Absent other interventions, a key metric for the success of social distancing is whether critical care capacities are exceeded. To avoid this, prolonged or intermittent social distancing may be necessary into 2022. Additional interventions, including expanded critical care capacity and an effective therapeutic, would improve the success of intermittent distancing and hasten the acquisition of herd immunity. Longitudinal serological studies are urgently needed to determine the extent and duration of immunity to SARS-CoV-2. Even in the event of apparent elimination, SARS-CoV-2 surveillance should be maintained because a resurgence in contagion could be possible as late as 2024.

2,203 citations

Journal ArticleDOI
31 Mar 2020-Science
TL;DR: The national emergency response appears to have delayed the growth and limited the size of the COVID-19 epidemic in China, averting hundreds of thousands of cases by 19 February (day 50), and suspending intracity public transport, closing entertainment venues, and banning public gatherings were associated with reductions in case incidence.
Abstract: Responding to an outbreak of a novel coronavirus [agent of coronavirus disease 2019 (COVID-19)] in December 2019, China banned travel to and from Wuhan city on 23 January 2020 and implemented a national emergency response. We investigated the spread and control of COVID-19 using a data set that included case reports, human movement, and public health interventions. The Wuhan shutdown was associated with the delayed arrival of COVID-19 in other cities by 2.91 days. Cities that implemented control measures preemptively reported fewer cases on average (13.0) in the first week of their outbreaks compared with cities that started control later (20.6). Suspending intracity public transport, closing entertainment venues, and banning public gatherings were associated with reductions in case incidence. The national emergency response appears to have delayed the growth and limited the size of the COVID-19 epidemic in China, averting hundreds of thousands of cases by 19 February (day 50).

1,582 citations

Journal ArticleDOI
Marina Pollán1, Beatriz Pérez-Gómez1, Roberto Pastor-Barriuso1, Jesús Oteo1, Miguel A. Hernán2, Miguel A. Hernán3, Mayte Pérez-Olmeda1, Jose L Sanmartín, Aurora Fernández-García4, Aurora Fernández-García1, Israel Cruz1, Nerea Fernández de Larrea1, Marta Molina, Francisco Rodríguez-Cabrera1, Mariano Martín, Paloma Merino-Amador4, Jose León Paniagua1, Juan F Muñoz-Montalvo, Faustino Blanco, Raquel Yotti1, Rodrigo Gutiérrez Fernández, Saturnino Mezcua Navarro, Matías Salinero Hernández, Manuel Cuenca-Estrella, Pablo Fernández-Navarro, Ana Avellón, Giovanni Fedele, Jesús Oteo Iglesias, María Teresa Pérez Olmeda, Maria Elena Martinez, Francisco D. Rodríguez-Cabrera1, Susana Padrones Fernández, José Manuel Rumbao Aguirre, José M. Navarro Marí, Begoña Palop Borrás, Ana Belén Pérez Jiménez, Manuel Rodríguez-Iglesias, Ana María Calvo Gascón, María Luz Lou Alcaine, Ignacio Donate Suárez, Oscar Suárez Álvarez, Mercedes Rodríguez Pérez, Margarita Cases Sanchís, Carlos Javier Villafáfila Gomila, Lluis Carbo Saladrigas, Adoración Hurtado Fernández, Antonio Oliver, Elías Castro Feliciano, María Noemí González Quintana, José María Barrasa Fernández, María Araceli Hernández Betancor, Melisa Hernández Febles, Leopoldo Martín Martín, Luis-Mariano López López, Teresa Ugarte Miota, Inés De Benito Población, María Sagrario Celada Pérez, María Natalia Vallés Fernández, Tomás Maté Enríquez, Miguel Villa Arranz, Marta Domínguez-Gil González, Isabel Fernández-Natal, Gregoria Megías Lobón, Juan Luis Muñoz Bellido, Pilar Ciruela, Ariadna Mas i Casals, Maria Doladé Botías, M. Angeles Marcos Maeso, Dúnia Pérez del Campo, Antonio Félix de Castro, Ramón Limón Ramírez, Maria Francisca Elías Retamosa, Manuela Rubio González, María Sinda Blanco Lobeiras, Alberto Fuentes Losada, Antonio Aguilera, Germán Bou, Yolanda Caro, Noemí Marauri, Luis Miguel Soria Blanco, Isabel González, Montserrat Hernández Pascual, Roberto Alonso Fernández, Natalia Cabrera Castro, Aurora Tomás Lizcano, Cristóbal Ramírez Almagro, M. Hernández, Nieves Ascunce Elizaga, María Ederra Sanz, Carmen Ezpeleta Baquedano, Ana Bustinduy Bascaran, Susana Iglesias Tamayo, Luis Elorduy Otazua, Rebeca Benarroch Benarroch, Jesús Lopera Flores, Antonia Vázquez de la Villa 
TL;DR: In this paper, a nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection in Spain at national and regional level.

1,435 citations