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Ejima K, Ajelli M, Singh A, Chua HK, Ponce L, Wang Y, Jeong YD, Iwami S, Shibuya K, Taniguchi K, Ohmagari N, Chia PY, Ong SWX, Tan KB, Lye DC, Young BE. Age- and vaccination status-dependent isolation guidelines based on simulation of SARS-CoV-2 Delta cases in Singapore. COMMUNICATIONS MEDICINE 2025; 5:76. [PMID: 40082681 PMCID: PMC11906760 DOI: 10.1038/s43856-025-00797-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 03/05/2025] [Indexed: 03/16/2025] Open
Abstract
BACKGROUND In the absence of effective pharmaceutical interventions early in an infectious disease outbreak, non-pharmaceutical measures, especially isolating infected individuals, critically limit its impact. The ongoing COVID-19 pandemic has sparked debates on optimal isolation guidelines. This study proposes a variable isolation period approach (variable-period approach), tailoring isolation durations for distinct population groups with varied viral load dynamics. METHODS To compare our variable-period approach with a fixed-period strategy, we developed a simulation model generating synthetic longitudinal SARS-CoV-2 viral load data. The data was generated from the viral dynamics model parameterized using SARS-CoV-2 Delta patient data in Singapore, accounting for age and vaccination status. RESULTS Findings show that age and vaccination status significantly influence viral dynamics, with younger age and vaccination linked to shorter viral shedding durations. The variable-period framework suggests longer isolation lengths for older and unvaccinated individuals. By setting the leaking risk (risk of remaining infectious at the end of isolation) below 10%, the optimal fixed-period isolation is 14 days, with an average excess isolation burden of 7.4 unnecessary days. In contrast, the variable-period guideline reduces the excess isolation burden to 6.0 days, with the optimal isolation periods ranging from 9 to 16 days, depending on the population group. We confirmed similar results when we used the effective reproduction number as an alternative to the leaking risk. CONCLUSIONS In this case, study using the SARS-CoV-2 Delta variant, our analysis demonstrates that unnecessary time spent in isolation can be reduced by adopting variable-period guidelines based on patient characteristics.
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Affiliation(s)
- Keisuke Ejima
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
- The Tokyo Foundation for Policy Research, Tokyo, Japan.
| | - Marco Ajelli
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Ananya Singh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Hoong Kai Chua
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Luis Ponce
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Yuqian Wang
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Yong Dam Jeong
- Interdisciplinary Biology Laboratory (iBLab), Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Shingo Iwami
- Interdisciplinary Biology Laboratory (iBLab), Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- Institute of Mathematics for Industry, Kyushu University, Fukuoka, Japan
- Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Kyoto, Japan
- NEXT-Ganken Program, Japanese Foundation for Cancer Research (JFCR), Tokyo, Japan
- Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), RIKEN, Saitama, Japan
- Science Groove Inc, Fukuoka, Japan
| | - Kenji Shibuya
- The Tokyo Foundation for Policy Research, Tokyo, Japan
| | | | - Norio Ohmagari
- Disease Control and Prevention Center, National Center for Global Health and Medicine Hospital, Tokyo, Japan
| | - Po Ying Chia
- National Centre for Infectious Diseases, Singapore, Singapore
- Tan Tock Seng Hospital, Singapore, Singapore
| | - Sean W X Ong
- National Centre for Infectious Diseases, Singapore, Singapore
- Tan Tock Seng Hospital, Singapore, Singapore
| | - Kelvin Bryan Tan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Division of Communicable Disease, Ministry of Health, Singapore, Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - David Chien Lye
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- National Centre for Infectious Diseases, Singapore, Singapore
- Tan Tock Seng Hospital, Singapore, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Barnaby E Young
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
- National Centre for Infectious Diseases, Singapore, Singapore.
- Tan Tock Seng Hospital, Singapore, Singapore.
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Majeed A, Quint JK, Bhatt S, Davies F, Islam N. Non-pharmaceutical interventions: evaluating challenges and priorities for future health shocks. BMJ 2024; 387:e080528. [PMID: 39374974 PMCID: PMC11450877 DOI: 10.1136/bmj-2024-080528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Affiliation(s)
- Azeem Majeed
- Department of Primary Care and Public Health, Imperial College London, London, UK
| | - Jennifer K Quint
- Department of Primary Care and Public Health, Imperial College London, London, UK
| | - Samir Bhatt
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - Firoza Davies
- Patient and public involvement representative, Leicester, UK
| | - Nazrul Islam
- School of Primary Care, Population Sciences and Medical Education, University of Southampton, Southampton, UK
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Espenhain L, Ethelberg S, Mortensen LH, Christiansen LE. Automated local lockdowns for SARS-CoV-2 epidemic control-assessment of effect by controlled interrupted time series analysis. IJID REGIONS 2024; 12:100380. [PMID: 38911235 PMCID: PMC11186853 DOI: 10.1016/j.ijregi.2024.100380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 06/25/2024]
Abstract
Objectives During the COVID-19 pandemic, broad non-pharmaceutical interventions such as national lockdowns were effective but had significant drawbacks, prompting targeted approaches, such as Denmark's localized lockdowns, based on specific epidemiological criteria. This study evaluates the effect of Denmark's automated local lockdown strategy on epidemic control to inform future response. Methods This was a register-based controlled interrupted time series analysis, examining SARS-CoV-2 infection rates in Danish parishes from March to September 2021. The matching of control parishes was based on location, time, and pre-lockdown infection trends, with the lockdown's start defined as the day after a parish exceeded the lockdown criteria. Follow-up included 3-week pre-lockdown and 2-week post-lockdown. Results A total of 30 parishes were mandated to lockdown, approximately 3.5% of the population of Denmark. A total of 94 control parishes were used as 109 controls. The decrease in the incidence during the 2-week follow-up period after the initiation of the lockdown was 13% points higher in case parishes: in case parishes, the incidence was reduced by 78% compared with 65% in control parishes. Conclusions Our findings demonstrate that local lockdowns did have a positive effect in mitigating the spread of the SARS-CoV-2 virus, making them valuable in the fight against the COVID-19 pandemic and an important alternative to national lockdowns.
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Affiliation(s)
- Laura Espenhain
- Department of Infectious Disease epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Steen Ethelberg
- Department of Infectious Disease epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Laust Hvas Mortensen
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Statistics Denmark, Copenhagen, Denmark
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Le NH, Hillus D, Tober-Lau P, Sander LE. [Vaccinations as a key to pandemic management - Lessons learned from the COVID-19 pandemic]. Dtsch Med Wochenschr 2023; 148:1557-1563. [PMID: 38052219 PMCID: PMC10923633 DOI: 10.1055/a-2124-2366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Pandemics and epidemic outbreaks caused by emerging pathogens can usually only be curbed in the longterm through establishment of protective population-wide immunity. With the unprecedented rapid development and supply of highly effective vaccines against COVID-19, science and industry delivered the critical medical breakthrough for the successful management of the COVID-19 pandemic. By May 2023, WHO could end the public health emergency. Nevertheless, the pandemic and its consequences for medicine, science, and society continue to reverberate. This article reviews at the development and implementation of COVID-19 vaccines, focusing on the situation in Germany, and seeks to draw lessons from the past three years to improve our readiness to combat future outbreaks and pandemics more effectively.
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Affiliation(s)
| | | | | | - Leif Erik Sander
- Korrespondenzadresse Prof. Dr. med. Leif Erik Sander Klinik für Infektiologie und Intensivmedizin
Charité Universitätsmedizin BerlinCharitéplatz 110117 Berlin
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