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Houy N, Flaig J. Value of information dynamics in Disease X vaccine clinical trials. Vaccine 2024; 42:1521-1533. [PMID: 38311534 DOI: 10.1016/j.vaccine.2024.01.063] [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] [Received: 06/11/2023] [Revised: 12/29/2023] [Accepted: 01/19/2024] [Indexed: 02/06/2024]
Abstract
BACKGROUND Solutions have been proposed to accelerate the development and rollout of vaccines against a hypothetical disease with epidemic or pandemic potential called Disease X. This may involve resolving uncertainties regarding the disease and the new vaccine. However the value for public health of collecting this information will depend on the time needed to perform research, but also on the time needed to produce vaccine doses. We explore this interplay, and its effect on the decision on whether or not to perform research. METHOD We simulate numerically the emergence and transmission of a disease in a population using a susceptible-infected-recovered (SIR) compartmental model with vaccination. Uncertainties regarding the disease and the vaccine are represented by parameter prior distributions. We vary the date at which vaccine doses are available, and the date at which information about parameters becomes available. We use the expected value of perfect information (EVPI) and the expected value of partially perfect information (EVPPI) to measure the value of information. RESULTS As expected, information has less or no value if it comes too late, or (equivalently) if it can only be used too late. However we also find non trivial dynamics for shorter durations of vaccine development. In this parameter area, it can be optimal to implement vaccination without waiting for information depending on the respective durations of dose production and of clinical research. CONCLUSION We illustrate the value of information dynamics in a Disease X outbreak scenario, and present a general approach to properly take into account uncertainties and transmission dynamics when planning clinical research in this scenario. Our method is based on numerical simulation and allows us to highlight non trivial effects that cannot otherwise be investigated.
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Affiliation(s)
- Nicolas Houy
- University of Lyon, Lyon F-69007, France; CNRS, GATE Lyon Saint-Etienne, F-69007, France.
| | - Julien Flaig
- Epidemiology and Modelling of Infectious Diseases (EPIMOD), Lyon F-69002, France.
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Yokomichi H, Mochizuki M, Horiuchi S, Kushima M, Shinohara R, Kojima R, Ooka T, Akiyama Y, Miyake K, Otawa S, Yamagata Z. Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS). Prev Med 2023; 173:107599. [PMID: 37391036 DOI: 10.1016/j.ypmed.2023.107599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/13/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023]
Abstract
We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.
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Affiliation(s)
- Hiroshi Yokomichi
- Department of Epidemiology and Environmental Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Mie Mochizuki
- Department of Paediatrics, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Sayaka Horiuchi
- Department of Epidemiology and Environmental Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Megumi Kushima
- Centre for Birth Cohort Studies, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Ryoji Shinohara
- Centre for Birth Cohort Studies, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Reiji Kojima
- Department of Health Sciences, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Tadao Ooka
- Department of Health Sciences, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Yuka Akiyama
- Department of Health Sciences, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Kunio Miyake
- Department of Epidemiology and Environmental Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Sanae Otawa
- Centre for Birth Cohort Studies, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
| | - Zentaro Yamagata
- Centre for Birth Cohort Studies, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan; Department of Health Sciences, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.
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Butzin-Dozier Z, Athni TS, Benjamin-Chung J. A Review of the Ring Trial Design for Evaluating Ring Interventions for Infectious Diseases. Epidemiol Rev 2022; 44:29-54. [PMID: 35593400 PMCID: PMC10362935 DOI: 10.1093/epirev/mxac003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 03/25/2022] [Accepted: 05/12/2022] [Indexed: 12/29/2022] Open
Abstract
In trials of infectious disease interventions, rare outcomes and unpredictable spatiotemporal variation can introduce bias, reduce statistical power, and prevent conclusive inferences. Spillover effects can complicate inference if individual randomization is used to gain efficiency. Ring trials are a type of cluster-randomized trial that may increase efficiency and minimize bias, particularly in emergency and elimination settings with strong clustering of infection. They can be used to evaluate ring interventions, which are delivered to individuals in proximity to or contact with index cases. We conducted a systematic review of ring trials, compare them with other trial designs for evaluating ring interventions, and describe strengths and weaknesses of each design. Of 849 articles and 322 protocols screened, we identified 26 ring trials, 15 cluster-randomized trials, 5 trials that randomized households or individuals within rings, and 1 individually randomized trial. The most common interventions were postexposure prophylaxis (n = 23) and focal mass drug administration and screening and treatment (n = 7). Ring trials require robust surveillance systems and contact tracing for directly transmitted diseases. For rare diseases with strong spatiotemporal clustering, they may have higher efficiency and internal validity than cluster-randomized designs, in part because they ensure that no clusters are excluded from analysis due to zero cluster incidence. Though more research is needed to compare them with other types of trials, ring trials hold promise as a design that can increase trial speed and efficiency while reducing bias.
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Bo Y, Wang H. Materials‐based vaccines for infectious diseases. WIRES NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1824. [PMID: 35708013 PMCID: PMC9541041 DOI: 10.1002/wnan.1824] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/16/2022] [Indexed: 12/03/2022]
Abstract
Infectious diseases that result from pathogen infection are among the leading causes of human death, with pathogens such as human immunodeficiency virus, malaria, influenza, and ongoing SARS‐COV‐2 viruses constantly threatening the global population. While the mechanisms behind various infectious diseases are not entirely clear and thus retard the development of effective therapeutics, vaccines have served as a universal approach to containing infectious diseases. However, conventional vaccines that solely consist of antigens or simply mix antigens and adjuvants have failed to control various highly infective or deadly pathogens. Biomaterials‐based vaccines have provided a promising solution due to their ability to synergize the function of antigens and adjuvants, troubleshoot delivery issues, home and manipulate immune cells in situ. In this review, we will summarize different types of materials‐based vaccines for generating cellular and humoral responses against pathogens and discuss the design criteria for amplifying the efficacy of materials‐based vaccines against infectious diseases. This article is categorized under:Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease
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Affiliation(s)
- Yang Bo
- Department of Materials Science and Engineering University of Illinois at Urbana‐Champaign Urbana Illinois USA
| | - Hua Wang
- Department of Materials Science and Engineering University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Cancer Center at Illinois (CCIL) Urbana Illinois USA
- Department of Bioengineering University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Carle College of Medicine University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign Urbana Illinois USA
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Gerhard T, Strom BL, Eyal N. Pandemic vaccine testing: combining conventional and challenge studies. Pharmacoepidemiol Drug Saf 2022; 31:710-715. [PMID: 35297119 PMCID: PMC9313872 DOI: 10.1002/pds.5429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 11/16/2022]
Abstract
Early into COVID, human challenge trials were considered, but usually as alternatives to conventional randomized controlled trials. Instead, assessment of authorized COVID vaccines, of further COVID vaccines, and of vaccines against future pandemics should combine both designs, in five different ways, including a wholly novel one that we elaborate, Viz., combining data from both designs to answer a single question.
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Affiliation(s)
- Tobias Gerhard
- Center for Pharmacoepidemiology and Treatment Science, Rutgers University, New Brunswick, NJ, USA.,Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, USA
| | - Brian L Strom
- Center for Pharmacoepidemiology and Treatment Science, Rutgers University, New Brunswick, NJ, USA.,Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Nir Eyal
- Center for Population-Level Bioethics, Rutgers Biomedical and Health Sciences, New Brunswick, NJ, USA.,Department of Philosophy, Rutgers University, New Brunswick, NJ, USA.,Department of Health Behavior, Society and Policy, Rutgers School of Public Health, Piscataway, NJ, USA
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Grayling MJ, Wason JMS, Villar SS. Response adaptive intervention allocation in stepped-wedge cluster randomized trials. Stat Med 2022; 41:1081-1099. [PMID: 35064595 PMCID: PMC7612601 DOI: 10.1002/sim.9317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 11/30/2021] [Accepted: 12/22/2021] [Indexed: 11/09/2022]
Abstract
BACKGROUND Stepped-wedge cluster randomized trial (SW-CRT) designs are often used when there is a desire to provide an intervention to all enrolled clusters, because of a belief that it will be effective. However, given there should be equipoise at trial commencement, there has been discussion around whether a pre-trial decision to provide the intervention to all clusters is appropriate. In pharmaceutical drug development, a solution to a similar desire to provide more patients with an effective treatment is to use a response adaptive (RA) design. METHODS We introduce a way in which RA design could be incorporated in an SW-CRT, permitting modification of the intervention allocation during the trial. The proposed framework explicitly permits a balance to be sought between power and patient benefit considerations. A simulation study evaluates the methodology. RESULTS In one scenario, for one particular RA design, the proportion of cluster-periods spent in the intervention condition was observed to increase from 32.2% to 67.9% as the intervention effect was increased. A cost of this was a 6.2% power drop compared to a design that maximized power by fixing the proportion of time in the intervention condition at 45.0%, regardless of the intervention effect. CONCLUSIONS An RA approach may be most applicable to settings for which the intervention has substantial individual or societal benefit considerations, potentially in combination with notable safety concerns. In such a setting, the proposed methodology may routinely provide the desired adaptability of the roll-out speed, with only a small cost to the study's power.
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Affiliation(s)
- Michael J Grayling
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - James M S Wason
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Sofía S Villar
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
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Vilakati S, Mngadi N, Benjamin-Chung J, Dlamini N, Dufour MSK, Whittemore B, Bhangu K, Prach LM, Baltzell K, Nhlabathi N, Malambe C, Dlamini B, Helb D, Greenhouse B, Maphalala G, Pindolia D, Kalungero M, Tesfa G, Gosling R, Ntshalintshali N, Kunene S, Hsiang MS. Effectiveness and safety of reactive focal mass drug administration (rfMDA) using dihydroartemisinin-piperaquine to reduce malaria transmission in the very low-endemic setting of Eswatini: a pragmatic cluster randomised controlled trial. BMJ Glob Health 2021; 6:e005021. [PMID: 34193475 PMCID: PMC8246301 DOI: 10.1136/bmjgh-2021-005021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/30/2021] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION To reduce malaria transmission in very low-endemic settings, screening and treatment near index cases (reactive case detection (RACD)), is widely practised, but the rapid diagnostic tests (RDTs) used miss low-density infections. Reactive focal mass drug administration (rfMDA) may be safe and more effective. METHODS We conducted a pragmatic cluster randomised controlled trial in Eswatini, a very low-endemic setting. 77 clusters were randomised to rfMDA using dihydroartemisin-piperaquine (DP) or RACD involving RDTs and artemether-lumefantrine. Interventions were delivered by the local programme. An intention-to-treat analysis was used to compare cluster-level cumulative confirmed malaria incidence among clusters with cases. Secondary outcomes included safety and adherence. RESULTS From September 2015 to August 2017, 222 index cases from 47 clusters triggered 46 RACD events and 64 rfMDA events. RACD and rfMDA were delivered to 1455 and 1776 individuals, respectively. Index case coverage was 69.5% and 62.4% for RACD and rfMDA, respectively. Adherence to DP was 98.7%. No serious adverse events occurred. For rfMDA versus RACD, cumulative incidences (per 1000 person-years) of all malaria were 2.11 (95% CI 1.73 to 2.59) and 1.97 (95% CI 1.57 to 2.47), respectively; and of locally acquired malaria, they were 1.29 (95% CI 1.00 to 1.67) and 0.97 (95% CI 0.71 to 1.34), respectively. Adjusting for imbalance in baseline incidence, incidence rate ratio for rfMDA versus RACD was 0.95 (95% CI 0.55 to 1.65) for all malaria and 0.82 (95% CI 0.40 to 1.71) for locally acquired malaria. Similar results were obtained in a per-protocol analysis that excluded clusters with <80% index case coverage. CONCLUSION In a very low-endemic, real-world setting, rfMDA using DP was safe, but did not lower incidence compared with RACD, potentially due to insufficient coverage and/or power. To assess impact of interventions in very low-endemic settings, improved coverage, complementary interventions and adaptive ring trial designs may be needed. TRIAL REGISTRATION NUMBER NCT02315690.
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Affiliation(s)
| | | | - Jade Benjamin-Chung
- Epidemiology & Biostatistics, University of California, Berkeley, California, USA
- Malaria Elimination Initiative, University of California, San Francisco, California, USA
| | - Nomcebo Dlamini
- National Malaria Program, Ministry of Health, Manzini, Eswatini
| | - Mi-Suk Kang Dufour
- Epidemiology & Biostatistics, University of California, Berkeley, California, USA
- Medicine, University of California, San Francisco, California, USA
| | - Brooke Whittemore
- Pediatrics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Lisa M Prach
- Malaria Elimination Initiative, University of California, San Francisco, California, USA
| | - Kimberly Baltzell
- Family Health Care Nursing, University of California, San Francisco, California, USA
| | | | | | | | - Danica Helb
- Medicine, University of California, San Francisco, California, USA
| | - Bryan Greenhouse
- Medicine, University of California, San Francisco, California, USA
| | - Gugu Maphalala
- National Clinical Laboratory Services, Mbabane, Swaziland
| | | | | | - Getahun Tesfa
- Paediatrics, Raleigh Fitkin Memorial Hospital, Manzini, Swaziland
| | - Roly Gosling
- Malaria Elimination Initiative, University of California, San Francisco, California, USA
| | | | - Simon Kunene
- National Malaria Program, Ministry of Health, Manzini, Eswatini
| | - Michelle S Hsiang
- Malaria Elimination Initiative, University of California, San Francisco, California, USA
- Pediatrics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Pediatrics, University of California, San Francisco, San Francisco, California, USA
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Zhou J, Krishnan N, Jiang Y, Fang RH, Zhang L. Nanotechnology for virus treatment. NANO TODAY 2021; 36:101031. [PMID: 33519948 PMCID: PMC7836394 DOI: 10.1016/j.nantod.2020.101031] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 04/14/2023]
Abstract
The continued emergence of novel viruses poses a significant threat to global health. Uncontrolled outbreaks can result in pandemics that have the potential to overburden our healthcare and economic systems. While vaccination is a conventional modality that can be employed to promote herd immunity, antiviral vaccines can only be applied prophylactically and do little to help patients who have already contracted viral infections. During the early stages of a disease outbreak when vaccines are unavailable, therapeutic antiviral drugs can be used as a stopgap solution. However, these treatments do not always work against emerging viral strains and can be accompanied by adverse effects that sometimes outweigh the benefits. Nanotechnology has the potential to overcome many of the challenges facing current antiviral therapies. For example, nanodelivery vehicles can be employed to drastically improve the pharmacokinetic profile of antiviral drugs while reducing their systemic toxicity. Other unique nanomaterials can be leveraged for their virucidal or virus-neutralizing properties. In this review, we discuss recent developments in antiviral nanotherapeutics and provide a perspective on the application of nanotechnology to the SARS-CoV-2 outbreak and future virus pandemics.
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Affiliation(s)
- Jiarong Zhou
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nishta Krishnan
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Yao Jiang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ronnie H Fang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Liangfang Zhang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
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Eyal N, Lipsitch M. Testing SARS-CoV-2 vaccine efficacy through deliberate natural viral exposure. Clin Microbiol Infect 2021; 27:372-377. [PMID: 33421580 PMCID: PMC7787506 DOI: 10.1016/j.cmi.2020.12.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/19/2020] [Accepted: 12/24/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND A vaccine trial with a conventional challenge design can be very fast once it starts, but it requires a long prior process, in part to grow and standardize challenge virus in the laboratory. This detracts somewhat from its overall promise for accelerated efficacy testing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidates, and from the ability of developing countries and small companies to conduct it. AIMS We set out to identify a challenge design that avoids this part of the long prior process. SOURCES Literature in trial design (including a proof of concept flu challenge trial by B. Killingley et al.), vaccinology, medical ethics, and various aspects of COVID response. CONTENT A challenge design with deliberate natural viral exposure avoids the need to grow culture. This new design is described and compared both to a conventional challenge design and to a conventional phase III field trial. In comparison, the proposed design has ethical, scientific, and feasibility strengths. IMPLICATIONS The proposed new design should be considered for future vaccine trials.
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Affiliation(s)
- Nir Eyal
- Center for Population-Level Bioethics, Rutgers University, New Brunswick, NJ, USA; Department of Health Behavior, Society and Policy, Rutgers School of Public Health, Piscataway, NJ, USA; Department of Philosophy, Rutgers University, New Brunswick, NJ, USA.
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
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Kennedy-Shaffer L, Lipsitch M. Statistical Properties of Stepped Wedge Cluster-Randomized Trials in Infectious Disease Outbreaks. Am J Epidemiol 2020; 189:1324-1332. [PMID: 32648891 PMCID: PMC7604531 DOI: 10.1093/aje/kwaa141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/11/2022] Open
Abstract
Randomized controlled trials are crucial for the evaluation of interventions such as vaccinations, but the design and analysis of these studies during infectious disease outbreaks is complicated by statistical, ethical, and logistical factors. Attempts to resolve these complexities have led to the proposal of a variety of trial designs, including individual randomization and several types of cluster randomization designs: parallel-arm, ring vaccination, and stepped wedge designs. Because of the strong time trends present in infectious disease incidence, however, methods generally used to analyze stepped wedge trials might not perform well in these settings. Using simulated outbreaks, we evaluated various designs and analysis methods, including recently proposed methods for analyzing stepped wedge trials, to determine the statistical properties of these methods. While new methods for analyzing stepped wedge trials can provide some improvement over previous methods, we find that they still lag behind parallel-arm cluster-randomized trials and individually randomized trials in achieving adequate power to detect intervention effects. We also find that these methods are highly sensitive to the weighting of effect estimates across time periods. Despite the value of new methods, stepped wedge trials still have statistical disadvantages compared with other trial designs in epidemic settings.
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Affiliation(s)
- Lee Kennedy-Shaffer
- Correspondence to Dr. Lee Kennedy-Shaffer, Department of Mathematics and Statistics, Vassar College, 124 Raymond Avenue, Box 226, Poughkeepsie, NY 12604 (e-mail: )
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Sigfrid L, Maskell K, Bannister PG, Ismail SA, Collinson S, Regmi S, Blackmore C, Harriss E, Longuere KS, Gobat N, Horby P, Clarke M, Carson G. Addressing challenges for clinical research responses to emerging epidemics and pandemics: a scoping review. BMC Med 2020; 18:190. [PMID: 32586391 PMCID: PMC7315698 DOI: 10.1186/s12916-020-01624-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/07/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Major infectious disease outbreaks are a constant threat to human health. Clinical research responses to outbreaks generate evidence to improve outcomes and outbreak control. Experiences from previous epidemics have identified multiple challenges to undertaking timely clinical research responses. This scoping review is a systematic appraisal of political, economic, administrative, regulatory, logistical, ethical and social (PEARLES) challenges to clinical research responses to emergency epidemics and solutions identified to address these. METHODS A scoping review. We searched six databases (MEDLINE, Embase, Global Health, PsycINFO, Scopus and Epistemonikos) for articles published from 2008 to July 2018. We included publications reporting PEARLES challenges to clinical research responses to emerging epidemics and pandemics and solutions identified to address these. Two reviewers screened articles for inclusion, extracted and analysed the data. RESULTS Of 2678 articles screened, 76 were included. Most presented data relating to the 2014-2016 Ebola virus outbreak or the H1N1 outbreak in 2009. The articles related to clinical research responses in Africa (n = 37), Europe (n = 8), North America (n = 5), Latin America and the Caribbean (n = 3) and Asia (n = 1) and/or globally (n = 22). A wide range of solutions to PEARLES challenges was presented, including a need to strengthen global collaborations and coordination at all levels and develop pre-approved protocols and equitable frameworks, protocols and standards for emergencies. Clinical trial networks and expedited funding and approvals were some solutions implemented. National ownership and community engagement from the outset were a key enabler for delivery. Despite the wide range of recommended solutions, none had been formally evaluated. CONCLUSIONS To strengthen global preparedness and response to the COVID-19 pandemic and future epidemics, identified solutions for rapid clinical research deployment, delivery, and dissemination must be implemented. Improvements are urgently needed to strengthen collaborations, funding mechanisms, global and national research capacity and capability, targeting regions vulnerable to epidemics and pandemics. Solutions need to be flexible to allow timely adaptations to context, and research led by governments of affected regions. Research communities globally need to evaluate their activities and incorporate lessons learnt to refine and rehearse collaborative outbreak response plans in between epidemics.
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Affiliation(s)
- Louise Sigfrid
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Oxford, OX3 7LG, UK.
| | - Katherine Maskell
- Deparment for Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, UK
| | - Peter G Bannister
- Deparment for Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, UK
| | - Sharif A Ismail
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Shelui Collinson
- School of Population Health and Environmental Sciences, King's College London, London, UK
| | - Sadie Regmi
- Department of Primary Care and Public Health, Imperial College London, London, UK
| | - Claire Blackmore
- University Hospitals of Derby and Burton NHS Foundation Trust, Derby, UK
| | - Eli Harriss
- Bodleian Health Care Libraries, University of Oxford, Oxford, UK
| | - Kajsa-Stina Longuere
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Oxford, OX3 7LG, UK
| | - Nina Gobat
- Nuffield Dep of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Peter Horby
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Oxford, OX3 7LG, UK
| | - Mike Clarke
- Evidence Aid, Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Gail Carson
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus, Oxford, OX3 7LG, UK
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Kennedy-Shaffer L, Lipsitch M. Statistical Properties of Stepped Wedge Cluster-Randomized Trials in Infectious Disease Outbreaks. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2020. [PMID: 32511544 DOI: 10.1101/2020.05.01.20087429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Randomized controlled trials are crucial for the evaluation of interventions such as vaccinations, but the design and analysis of these studies during infectious disease outbreaks is complicated by statistical, ethical, and logistical factors. Attempts to resolve these complexities have led to the proposal of a variety of trial designs, including individual randomization and several types of cluster randomization designs: parallel-arm, ring vaccination, and stepped wedge designs. Because of the strong time trends present in infectious disease incidence, however, methods generally used to analyze stepped wedge trials may not perform well in these settings. Using simulated outbreaks, we evaluate various designs and analysis methods, including recently proposed methods for analyzing stepped wedge trials, to determine the statistical properties of these methods. While new methods for analyzing stepped wedge trials can provide some improvement over previous methods, we find that they still lag behind parallel-arm cluster-randomized trials and individually-randomized trials in achieving adequate power to detect intervention effects. We also find that these methods are highly sensitive to the weighting of effect estimates across time periods. Despite the value of new methods, stepped wedge trials still have statistical disadvantages compared to other trial designs in epidemic settings.
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Billington J, Deschamps I, Erck SC, Gerberding JL, Hanon E, Ivol S, Shiver JW, Spencer JA, Van Hoof J. Developing Vaccines for SARS-CoV-2 and Future Epidemics and Pandemics: Applying Lessons from Past Outbreaks. Health Secur 2020; 18:241-249. [PMID: 32348165 PMCID: PMC7310201 DOI: 10.1089/hs.2020.0043] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The COVID-19 pandemic is a stark reminder of the heavy toll that emerging infectious diseases (EIDs) with epidemic and pandemic potential can inflict. Vaccine development, scale-up, and commercialization is a long, expensive, and risky enterprise that requires substantial upfront planning and offers no guarantee of success. EIDs are a particularly challenging target for global health preparedness, including for vaccine development. Insufficient attention has been given to challenges, lessons learned, and potential solutions to support and sustain vaccine industry engagement in vaccine development for EIDs. Drawing from lessons from the most recent Ebola epidemic in the Democratic Republic of the Congo, as well as the 2009 H1N1 influenza, 2014-2016 Ebola, and 2015-16 Zika outbreaks preceding it, we offer our perspective on challenges facing EID vaccine development and recommend additional solutions to prioritize in the near term. The 6 recommendations focus on reducing vaccine development timelines and increasing business certainty to reduce risks for companies. The global health security community has an opportunity to build on the current momentum to design a sustainable model for EID vaccines.
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Affiliation(s)
- John Billington
- John Billington, JD, MPH, is Director, Science Policy, and Emmanuel Hanon, PhD, DVM, is Senior Vice President, Head of R&D; both at GSK Vaccines, Wavre, Belgium
| | - Isabelle Deschamps
- Isabelle Deschamps, PhD, is Head of Global Vaccine Public Affairs; and John W. Shiver, PhD, is Senior Vice President R&D; both with Sanofi Pasteur, Lyon, France
| | - Stanley C. Erck
- Stanley C. Erck, MBA, is President and Chief Executive Officer, Novavax, Gaithersburg, MD
| | - Julie L. Gerberding
- Julie L. Gerberding, MD, MPH, is Executive Vice President and Chief Patient Officer, Strategic Communications, Global Public Policy, and Population Health; and Julia A. Spencer, PhD, is Associate Vice President, Global Public Policy; both with Merck & Co., Inc., Kenilworth, NJ
| | - Emmanuel Hanon
- John Billington, JD, MPH, is Director, Science Policy, and Emmanuel Hanon, PhD, DVM, is Senior Vice President, Head of R&D; both at GSK Vaccines, Wavre, Belgium
| | - Sabrina Ivol
- Sabrina Ivol is Senior Specialist, Policy; and Johan Van Hoof, MD, is Managing Director; both with Janssen Vaccines & Prevention BV, Janssen Pharmaceuticals R&D, Leiden, Netherlands
| | - John W. Shiver
- Isabelle Deschamps, PhD, is Head of Global Vaccine Public Affairs; and John W. Shiver, PhD, is Senior Vice President R&D; both with Sanofi Pasteur, Lyon, France
| | - Julia A. Spencer
- Julie L. Gerberding, MD, MPH, is Executive Vice President and Chief Patient Officer, Strategic Communications, Global Public Policy, and Population Health; and Julia A. Spencer, PhD, is Associate Vice President, Global Public Policy; both with Merck & Co., Inc., Kenilworth, NJ
| | - Johan Van Hoof
- Sabrina Ivol is Senior Specialist, Policy; and Johan Van Hoof, MD, is Managing Director; both with Janssen Vaccines & Prevention BV, Janssen Pharmaceuticals R&D, Leiden, Netherlands
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弓 孟, 刘 莉, 吴 琛, 杨 越, 沈 杨, 李 杰, 林 凯, 郭 怡, 魏 红, 徐 泽, 朱 宏. [Conducting clinical studies during the epidemics of communicable diseases: perspectives of methodology and health economics]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2020; 40:353-357. [PMID: 32376587 PMCID: PMC7167318 DOI: 10.12122/j.issn.1673-4254.2020.03.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Indexed: 12/21/2022]
Abstract
In the setting of epidemics of communicable diseases, early initiation of epidemiological and clinical data collection and analysis and conducting relevant researches are essential to the success of epidemic containment. The coronavirus disease 2019 (COVID-19), starting initially as an epidemic in China in late 2019 and now becoming a pandemic globally, poses grave challenges to the global health care systems while also provides an opportunity for studying infectious diseases in the perspective of methodology. The authors propose the evaluation methods for case reports, randomized controlled trials (RCTs), real-world evidence studies and health economics researches during an epidemic. Case reports, which are of important value for health care workers during outbreaks of infectious diseases, should be written in standard format and style and published following a strict peer review process. RCTs provides the gold standard for evaluating the effectiveness of a given treatment for the patients from the outbreaks. We review the potential challenges faced in conducting RCTs during the outbreaks. The real-world data collected from the cases in designated hospitals allow the verification of the safety and effectiveness of the intervention measures. The data from health economics research also provide important support for optimizing communicable disease prevention and control strategies. Herein we summarize the health economics research methods, study design, and technical points during the outbreaks. We recommend that clinical research and health economics research be incorporated into the prevention and control plan and measures be taken to ensure both the standards and feasibility of these studies to improve the response capacity against outbreaks of communicable diseases.
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Affiliation(s)
- 孟春 弓
- 南方医科大学 卫生与健康管理研究院,广东 广州 510515Institute of Health Management, Southern Medical University, Guangzhou 510515, China
| | - 莉 刘
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 琛 吴
- 神州数码医疗科技股份有限公司,北京 100085Digital China Health Technologies Co. Ltd, Beijing 100085, China
| | - 越 杨
- 神州数码医疗科技股份有限公司,北京 100085Digital China Health Technologies Co. Ltd, Beijing 100085, China
| | - 杨 沈
- 神州数码医疗科技股份有限公司,北京 100085Digital China Health Technologies Co. Ltd, Beijing 100085, China
| | - 杰 李
- 神州数码医疗科技股份有限公司,北京 100085Digital China Health Technologies Co. Ltd, Beijing 100085, China
| | - 凯程 林
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 怡 郭
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 红云 魏
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 泽宇 徐
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 宏 朱
- 南方医科大学 卫生与健康管理研究院,广东 广州 510515Institute of Health Management, Southern Medical University, Guangzhou 510515, China
- 南方医科大学 南方医院,广东 广州 510515Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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Bedford J, Farrar J, Ihekweazu C, Kang G, Koopmans M, Nkengasong J. A new twenty-first century science for effective epidemic response. Nature 2019; 575:130-136. [PMID: 31695207 PMCID: PMC7095334 DOI: 10.1038/s41586-019-1717-y] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 09/24/2019] [Indexed: 12/20/2022]
Abstract
With rapidly changing ecology, urbanization, climate change, increased travel and fragile public health systems, epidemics will become more frequent, more complex and harder to prevent and contain. Here we argue that our concept of epidemics must evolve from crisis response during discrete outbreaks to an integrated cycle of preparation, response and recovery. This is an opportunity to combine knowledge and skills from all over the world-especially at-risk and affected communities. Many disciplines need to be integrated, including not only epidemiology but also social sciences, research and development, diplomacy, logistics and crisis management. This requires a new approach to training tomorrow's leaders in epidemic prevention and response.
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Affiliation(s)
| | | | | | - Gagandeep Kang
- Translational Health Science and Technology Institute, Faridabad, India
| | - Marion Koopmans
- Department of Viroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - John Nkengasong
- Africa Centres for Disease Control and Prevention, African Union, Addis Ababa, Ethiopia
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Ellenberg SS, Keusch GT, Babiker AG, Edwards KM, Lewis RJ, Lundgren JD, Wells CD, Wabwire-Mangen F, McAdam KPWJ. Rigorous Clinical Trial Design in Public Health Emergencies Is Essential. Clin Infect Dis 2019; 66:1467-1469. [PMID: 29177461 DOI: 10.1093/cid/cix1032] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/18/2017] [Indexed: 12/18/2022] Open
Abstract
Randomized clinical trials are the most reliable approaches to evaluating the effects of new treatments and vaccines. During the 2014-2015 West African Ebola epidemic, many argued that such trials were neither ethical nor feasible in an environment of limited health infrastructure and severe disease with a high fatality rate. Consensus among the numerous organizations providing help to the affected areas was never achieved, resulting in fragmented collaboration, delayed study initiation, and ultimately failure to provide definitive evidence on the efficacy of treatments and vaccines. Randomized trials were in fact approved by local ethics boards and initiated, demonstrating that randomized trials, even in such difficult circumstances, are feasible. Improved planning and collaboration among research and humanitarian organizations, and affected communities, in the interepidemic periods are needed to ensure that questions regarding the efficacy of vaccines and treatments can be definitively answered during future public health emergencies.
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Affiliation(s)
- Susan S Ellenberg
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Gerald T Keusch
- Departments of Medicine and Global Health, Boston University Schools of Medicine and Public Health, Massachusetts
| | - Abdel G Babiker
- Medical Research Council Clinical Trials Unit, University College London, United Kingdom
| | - Kathryn M Edwards
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Roger J Lewis
- Department of Emergency Medicine, Harbor-UCLA Medical Center, University of California, Los Angeles, California
| | - Jens D Lundgren
- Department of Infectious Diseases, University of Copenhagen, Denmark
| | - Charles D Wells
- Infectious Diseases Unit, Sanofi-US, Bridgewater, New Jersey
| | - Fred Wabwire-Mangen
- Department of Epidemiology, Makerere University School of Public Health, Kampala, Uganda
| | - Keith P W J McAdam
- Department of Clinical and Tropical Medicine, London School of Hygiene and Tropical Medicine, United Kingdom
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Binik A. Delaying and withholding interventions: ethics and the stepped wedge trial. JOURNAL OF MEDICAL ETHICS 2019; 45:662-667. [PMID: 31341013 DOI: 10.1136/medethics-2018-105138] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 06/12/2019] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Ethics has been identified as a central reason for choosing the stepped wedge trial over other kinds of trial designs. The potential advantage of the stepped wedge design is that it provides all arms of the trial with the active intervention over the course of the study. Some groups receive it later than others, but the study intervention is not withheld from any group. This feature of the stepped wedge design seems particularly ethically advantageous in two instances: (1) when the study intervention appears especially likely to be effective and (2) when the consequences of not receiving the intervention may be dire. But despite an increase in the use of the stepped wedge design and appeals to its ethical superiority as the motivation for its selection, there has been limited attention to the stepped wedge trial in the ethics literature. In the following, I examine whether there are persuasive ethical reasons to prefer or to require a stepped wedge trial. I argue that while the stepped wedge design is ethically permissible, it is not morally superior to other kinds of trials. To this end, I examine the ethical justification for providing, withholding, and delaying interventions in research.
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Affiliation(s)
- Ariella Binik
- Department of Philosophy, McMaster University, Hamilton, Ontario, Canada
- Institute on Ethics & Policy for Innovation, McMaster University, Hamilton, Ontario, Canada
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Cauchemez S, Hoze N, Cousien A, Nikolay B, Ten Bosch Q. How Modelling Can Enhance the Analysis of Imperfect Epidemic Data. Trends Parasitol 2019; 35:369-379. [PMID: 30738632 PMCID: PMC7106457 DOI: 10.1016/j.pt.2019.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 01/02/2023]
Abstract
Mathematical models play an increasingly important role in our understanding of the transmission and control of infectious diseases. Here, we present concrete examples illustrating how mathematical models, paired with rigorous statistical methods, are used to parse data of different levels of detail and breadth and estimate key epidemiological parameters (e.g., transmission and its determinants, severity, impact of interventions, drivers of epidemic dynamics) even when these parameters are not directly measurable, when data are limited, and when the epidemic process is only partially observed. Finally, we assess the hurdles to be taken to increase availability and applicability of these approaches in an effort to ultimately enhance their public health impact. Many data can be used to estimate the transmission potential of a pathogen, including descriptions of the transmission chains, human cluster sizes, sources of infection, and epidemic curves. An important agenda in public health is understanding the impact of control methods. However, the dynamic nature of epidemics makes this task challenging. Models can disentangle the natural course of outbreaks from the effect of external factors. In the absence of reliable surveillance data, models can reconstruct epidemic history by combining age-specific seroprevalence data with an understanding of the natural history of infection. Mechanisms of immunity are hard to observe at an individual level, yet they affect population-level dynamics. Models can tease out such signatures. Morbidity and mortality can be difficult to estimate when many infections are unobserved and severe infections are reported more often. Models can be used to correct for under-reporting and selection bias.
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Affiliation(s)
- Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France; All the authors made equal contributions.
| | - Nathanaël Hoze
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France; All the authors made equal contributions
| | - Anthony Cousien
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France; All the authors made equal contributions
| | - Birgit Nikolay
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France; All the authors made equal contributions
| | - Quirine Ten Bosch
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France; All the authors made equal contributions
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Lipsitch M, Santillana M. Enhancing Situational Awareness to Prevent Infectious Disease Outbreaks from Becoming Catastrophic. Curr Top Microbiol Immunol 2019; 424:59-74. [DOI: 10.1007/82_2019_172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Abstract
In a Policy Forum, Marc Lipsitch and colleagues discuss trial design issues in infectious disease outbreaks.
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Affiliation(s)
- Rebecca Kahn
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Annette Rid
- Department of Global Health & Social Medicine, King’s College London, London, United Kingdom
| | - Peter G. Smith
- MRC Tropical Epidemiology Group, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Nir Eyal
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
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Hitchings MDT, Lipsitch M, Wang R, Bellan SE. Competing Effects of Indirect Protection and Clustering on the Power of Cluster-Randomized Controlled Vaccine Trials. Am J Epidemiol 2018. [PMID: 29522080 DOI: 10.1093/aje/kwy047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Power considerations for trials evaluating vaccines against infectious diseases are complicated by indirect protective effects of vaccination. While cluster-randomized controlled trials (cRCTs) are less statistically efficient than individually randomized controlled trials (iRCTs), a cRCT's ability to measure direct and indirect vaccine effects may mitigate the loss of efficiency due to clustering. Within cRCTs, the number and size of clusters affects 3 determinants of power: the effect size being measured, disease incidence, and intracluster correlation. We simulated trials conducted in a collection of small communities to assess how indirect protection and clustering affected the power of cRCTs and iRCTs during an emerging epidemic. Across diverse parameters, we found that within the same trial population, cRCTs were never more powerful than iRCTs, although the difference can be small. We also identified 2 effects that attenuated the loss of cRCT power traditionally associated with increased cluster size. First, if enrollment of fewer, larger clusters was performed to achieve higher vaccine coverage within vaccinated communities, this increased the effect to be measured and, consequently, power. Second, the greater rate of imported transmission in larger communities may increase the attack rate and similarly mitigate loss of power relative to a trial in many, smaller communities.
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Affiliation(s)
- Matt D T Hitchings
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Rui Wang
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Steven E Bellan
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, Georgia
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