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Domenech de Cellès M, Rohani P. Pertussis vaccines, epidemiology and evolution. Nat Rev Microbiol 2024:10.1038/s41579-024-01064-8. [PMID: 38907021 DOI: 10.1038/s41579-024-01064-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2024] [Indexed: 06/23/2024]
Abstract
Pertussis, which is caused by Bordetella pertussis, has plagued humans for at least 800 years, is highly infectious and can be fatal in the unvaccinated, especially very young infants. Although the rollout of whole-cell pertussis (wP) vaccines in the 1940s and 1950s was associated with a drastic drop in incidence, concerns regarding the reactogenicity of wP vaccines led to the development of a new generation of safer, acellular (aP) vaccines that have been adopted mainly in high-income countries. Over the past 20 years, some countries that boast high aP coverage have experienced a resurgence in pertussis, which has led to substantial debate over the basic immunology, epidemiology and evolutionary biology of the bacterium. Controversy surrounds the duration of natural immunity and vaccine-derived immunity, the ability of vaccines to prevent transmission and severe disease, and the impact of evolution on evading vaccine immunity. Resolving these issues is made challenging by incomplete detection of pertussis cases, the absence of a serological marker of immunity, modest sequencing of the bacterial genome and heterogeneity in diagnostic methods of surveillance. In this Review, we lay out the complexities of contemporary pertussis and, where possible, propose a parsimonious explanation for apparently incongruous observations.
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Affiliation(s)
| | - Pejman Rohani
- Odum School of Ecology, University of Georgia, Athens, GA, USA.
- Center of Ecology of Infectious Diseases, Athens, GA, USA.
- Department of Infectious Diseases, College for Veterinary Medicine, University of Georgia, Athens, GA, USA.
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Domenech de Cellès M, Wong A, Andrea Barrero Guevara L, Rohani P. Immunological heterogeneity informs estimation of the durability of vaccine protection. J R Soc Interface 2022; 19:20220070. [PMID: 35611620 PMCID: PMC9131131 DOI: 10.1098/rsif.2022.0070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022] Open
Abstract
Deciphering the properties of vaccines against an emerging pathogen is essential for optimizing immunization strategies. Early after vaccine roll-out, however, uncertainties about vaccine immunity raise the question of how much time is needed to estimate these properties, particularly the durability of vaccine protection. Here we designed a simulation study, based on a generic transmission model of vaccination, to simulate the impact of a breadth of vaccines with different mean (range: 10 months-2 years) and variability (coefficient of variation range: 50-100%) of the duration of protection. Focusing on the dynamics of SARS-CoV-2 in the year after start of mass immunization in Germany as a case study, we then assessed how confidently the duration of protection could be estimated under a range of epidemiological scenarios. We found that lower mean and higher heterogeneity facilitated estimation of the duration of vaccine protection. Across the vaccines tested, rapid waning and high heterogeneity permitted complete identification of the duration of protection; by contrast, slow waning and low heterogeneity allowed only estimation of the fraction of vaccinees with rapid loss of immunity. These findings suggest that limited epidemiological data can inform the duration of vaccine immunity. More generally, they highlight the need to carefully consider immunological heterogeneity when designing transmission models to evaluate vaccines.
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Affiliation(s)
| | - Anabelle Wong
- Infectious Disease Epidemiology group, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
- Institute of Public Health, Charité—Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Laura Andrea Barrero Guevara
- Infectious Disease Epidemiology group, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
- Institute of Public Health, Charité—Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Pejman Rohani
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
- Center for Influenza Disease & Emergence Research (CIDER), University of Georgia, Athens, GA 30602, USA
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Saeidpour A, Bansal S, Rohani P. Dissecting recurrent waves of pertussis across the boroughs of London. PLoS Comput Biol 2022; 18:e1009898. [PMID: 35421101 PMCID: PMC9041754 DOI: 10.1371/journal.pcbi.1009898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/26/2022] [Accepted: 02/04/2022] [Indexed: 11/19/2022] Open
Abstract
Pertussis has resurfaced in the UK, with incidence levels not seen since the 1980s. While the fundamental causes of this resurgence remain the subject of much conjecture, the study of historical patterns of pathogen diffusion can be illuminating. Here, we examined time series of pertussis incidence in the boroughs of Greater London from 1982 to 2013 to document the spatial epidemiology of this bacterial infection and to identify the potential drivers of its percolation. The incidence of pertussis over this period is characterized by 3 distinct stages: a period exhibiting declining trends with 4-year inter-epidemic cycles from 1982 to 1994, followed by a deep trough until 2006 and the subsequent resurgence. We observed systematic temporal trends in the age distribution of cases and the fade-out profile of pertussis coincident with increasing national vaccine coverage from 1982 to 1990. To quantify the hierarchy of epidemic phases across the boroughs of London, we used the Hilbert transform. We report a consistent pattern of spatial organization from 1982 to the early 1990s, with some boroughs consistently leading epidemic waves and others routinely lagging. To determine the potential drivers of these geographic patterns, a comprehensive parallel database of borough-specific features was compiled, comprising of demographic, movement and socio-economic factors that were used in statistical analyses to predict epidemic phase relationships among boroughs. Specifically, we used a combination of a feed-forward neural network (FFNN), and SHapley Additive exPlanations (SHAP) values to quantify the contribution of each covariate to model predictions. Our analyses identified a number of predictors of a borough's historical epidemic phase, specifically the age composition of households, the number of agricultural and skilled manual workers, latitude, the population of public transport commuters and high-occupancy households. Univariate regression analysis of the 2012 epidemic identified the ratio of cumulative unvaccinated children to the total population and population of Pakistan-born population to have moderate positive and negative association, respectively, with the timing of epidemic. In addition to providing a comprehensive overview of contemporary pertussis transmission in a large metropolitan population, this study has identified the characteristics that determine the spatial spread of this bacterium across the boroughs of London.
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Affiliation(s)
- Arash Saeidpour
- Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
| | - Shweta Bansal
- Department of Biology, Georgetown University, Washington, D.C., United States of America
| | - Pejman Rohani
- Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- Center for Influenza Disease & Emergence Research (CIDER), Athens, Georgia, United States of America
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Rane MS, Rohani P, Halloran ME. Durability of protection after 5 doses of acellular pertussis vaccine among 5-9 year old children in King County, Washington. Vaccine 2021; 39:6144-6150. [PMID: 34493409 PMCID: PMC9665886 DOI: 10.1016/j.vaccine.2021.08.070] [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: 06/04/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE Waning of immunity after vaccination with the acellular Pertussis (aP) vaccine has been proposed as one of the main reasons for pertussis resurgence in the US. In this study, we estimated time-varying vaccine effectiveness after 5 doses of aP vaccine. METHODS We conducted a retrospective cohort study among children 5-9 years old (born between 2008 and 2012) living in King County, Washington, USA, who participated in the Washington State Immunization Information System. We estimated time-varying vaccine effectiveness after 5 doses of aP using smoothed scaled Schoenfeld residuals obtained from fitting Cox proportional hazards models to the data as well as piecewise constant Poisson regression. RESULTS There were 55 pertussis cases in this cohort, of whom 22 (40%) were fully-vaccinated and 33 (60%) were under-vaccinated. Vaccine effectiveness (VE) remained high for up to 42 months after the fifth dose (VE(t) = 89%; 95% CI: 64%, 97%) as estimated using survival analysis methods and up to 4 years (VE(t) = 93%; 95% CI: 67%, 98%) as estimated using Poisson regression. CONCLUSION We did not find evidence for waning of vaccine effectiveness for up to four years after 5 doses of aP among 5 -9 years old children in King County, WA.
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Affiliation(s)
- Madhura S Rane
- Department of Epidemiology, University of Washington, Seattle, WA 98195, USA.
| | - Pejman Rohani
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - M Elizabeth Halloran
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
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Wehlin L, Ljungman M, Kühlmann-Berenzon S, Galanis I, Huygen K, Pierard D, Dalby T, Petridou E, Molnár Z, Carollo M, Ausiello CM, Lipnickiene V, Haider J, Aase A, Herstad TK, Rastawicki W, Rio C, Popovici O, De Ory Manchon F, Bacci S, Barkoff AM, Hänninen A, He Q, Hallander H. Pertussis seroprevalence among adults of reproductive age (20-39 years) in fourteen European countries. APMIS 2021; 129:556-565. [PMID: 34120372 DOI: 10.1111/apm.13165] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 12/01/2022]
Abstract
The reported incidence of pertussis in European countries varies considerably. We aimed to study specific Bordetella pertussis seroprevalence in Europe by measuring serum IgG antibody levels to pertussis toxin (anti-PT IgG). Fourteen national laboratories participated in this study including Belgium, Denmark, Finland, Greece, Hungary, Italy, Lithuania, Malta, Norway, Poland, Portugal, Romania, Spain, and Sweden. Each country collected approximately 250 samples (N = 7903) from the age groups 20-29 years (N = 3976) and 30-39 years (N = 3927) during 2010-2013. Samples were anonymous residual sera from diagnostic laboratories and were analyzed at the national laboratories by a Swedish reference method, a commercial ELISA kit, or were sent to Sweden for analysis. The median anti-PT IgG concentrations ranged from 4 to 13.6 IU/mL. The proportion of samples with anti-PT IgG ≥100 IU/mL, indicating a recent infection ranged from 0.2% (Hungary) to 5.7% (Portugal). The highest proportion of sera with anti-PT IgG levels between 50 and <100 IU/mL, indicating an infection within the last few years, was found in Portugal (12.3%) and Italy (13.9%). This study shows that the circulation of B. pertussis is quite extensive in adults, aged 20-39 years, despite well-established vaccination programs in Europe.
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Affiliation(s)
- Lena Wehlin
- The Public Health Agency of Sweden, Solna, Sweden
| | | | | | | | - Kris Huygen
- Scientific Institute of Public Health (Sciensano, WIV-ISP), Brussels, Belgium
| | | | - Tine Dalby
- Statens Serum Institut, Copenhagen, Denmark
| | - Evi Petridou
- Serology - Microbiology Department, "Aghia Sophia", Athens Children's Hospital, Athens, Greece
| | | | - Maria Carollo
- Core Facilities Technical Scientific Service, Istituto Superiore di Sanità, Rome, Italy
| | - Clara M Ausiello
- Core Facilities Technical Scientific Service, Istituto Superiore di Sanità, Rome, Italy
| | | | - Julie Haider
- Pathology Laboratorie, Pathology Department, Mater Dei Hospital, Valetta, Malta
| | - Audun Aase
- The Norwegian Institute of Public Health, Oslo, Norway
| | | | - Waldemar Rastawicki
- National Institute of Public Health-National Institute of Hygiene, Warsaw, Poland
| | - Carla Rio
- National Institute of Health, Dr. Ricardo Jorge, Lisbon, Portugal
| | | | | | - Sabrina Bacci
- European Centre for Disease Prevention and Control, Solna, Sweden
| | | | - Arno Hänninen
- University of Turku, Turku, Finland.,Turku University Hospital, Turku, Finland
| | - Qiushui He
- University of Turku, Turku, Finland.,Capital Medical University, Beijing, China
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Munro AD, Smallman-Raynor M, Algar AC. Long-term changes in endemic threshold populations for pertussis in England and Wales: A spatiotemporal analysis of Lancashire and South Wales, 1940-69. Soc Sci Med 2020; 288:113295. [PMID: 32921522 DOI: 10.1016/j.socscimed.2020.113295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/23/2020] [Accepted: 08/12/2020] [Indexed: 11/19/2022]
Abstract
Metapopulation dynamics play a critical role in driving endemic persistence and transmission of childhood infections. The endemic threshold concept, also referred to as critical community size (CCS), is a key example and is defined as the minimum population size required to sustain a continuous chain of infection transmission. The concept is fundamental to the implementation of effective vaccine-based disease control programmes. Vaccination serves to increase endemic threshold population size, promoting disease fadeout and eventual elimination of infection. To date, empirical investigations of the relationship between vaccination and endemic threshold population size have tended to focus on isolated populations in island communities. Very few studies have examined endemic threshold dynamics in 'mainland' regional populations with complex hierarchical spatial structures and varying levels of connectivity between subpopulations. The present paper provides the first spatially explicit analysis of the temporal changes in endemic threshold populations for one vaccine-preventable childhood infection (pertussis) in two dynamic regions of England and Wales: Lancashire and South Wales. Drawing upon weekly disease records of the Registrar-General of England and Wales over a 30-year period (January 1940-December 1969) regression techniques were used to estimate the endemic threshold size for pertussis in the two study regions. Survival analyses were performed to compare disease fadeout duration and probability for both regions in the pre-vaccine and vaccine eras, respectively. Our findings reveal the introduction of mass vaccination led to a considerable increase in threshold size for both Lancashire (~387,333) and South Wales (~1,460,667). Significant growth in fadeout duration was observed in the vaccine era for pertussis non-hotspots in both regions, consistent with geographical synchronisation of epidemic activity. Regional differences in endemic threshold populations reflect significant regional variations in spatial connectivity, population dispersion and level of geographical isolation.
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Affiliation(s)
- Alastair D Munro
- School of Geography, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | | | - Adam C Algar
- School of Geography, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Hubbard A, Trostle J, Cangemi I, Eisenberg JNS. Countering the Curse of Dimensionality: Exploring Data-generating Mechanisms Through Participant Observation and Mechanistic Modeling. Epidemiology 2019; 30:609-614. [PMID: 30985531 PMCID: PMC6548691 DOI: 10.1097/ede.0000000000001025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Alan Hubbard
- School of Public Health, University of California, Berkeley, CA, USA
| | - James Trostle
- Department of Anthropology, Trinity College, Hartford, CT, USA
| | - Ivan Cangemi
- School of Public Health, University of Michigan, Ann Arbor, MI, USA
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Domenech de Cellès M, King AA, Rohani P. Commentary: resolving pertussis resurgence and vaccine immunity using mathematical transmission models. Hum Vaccin Immunother 2018; 15:683-686. [PMID: 30457424 PMCID: PMC6988877 DOI: 10.1080/21645515.2018.1549432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 10/13/2018] [Indexed: 01/26/2023] Open
Abstract
The epidemiology of pertussis-a vaccine-preventable respiratory infection typically caused by the bacterium Bordetella pertussis-remains puzzling. Indeed, the disease seems nowhere close to eradication and has even re-emerged in certain countries-such as the US-that have maintained high vaccination coverage. Because the dynamics of pertussis are shaped by past vaccination and natural infection rates, with the relevant timescale spanning decades, the interpretation of such unexpected trends is not straightforward. In this commentary, we propose that mathematical transmission models play an essential role in helping to interpret the data and in closing knowledge gaps in pertussis epidemiology. We submit that recent advances in statistical inference methods now allow us to estimate key parameters, such as the nature and duration of vaccinal immunity, which have to date been difficult to quantify. We illustrate these points with the results of a recent study based on data from Massachusetts (Domenech de Cellès, Magpantay, King, and Rohani, Sci. Transl. Med. 2018;10: eaaj1748. doi:10.1126/scitranslmed.aaj1748), in which we used such methods to elucidate the mechanisms underlying the ongoing resurgence of pertussis. In addition, we list a number of safety checks that can be used to critically assess mathematical models. Finally, we discuss the remaining uncertainties surrounding pertussis vaccines, in particular the acellular vaccines used for teenage booster immunizations.
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Affiliation(s)
- M. Domenech de Cellès
- Biostatistics, Biomathematics, Pharmacoepidemiology, and Infectious Diseases (B2PHI) Unit, Institut Pasteur, Inserm U1181, University of Versailles St-Quentin-en-Yvelines
| | - A. A. King
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Mathematics, University of Michigan, Ann Arbor, MI, USA
- Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI, USA
| | - P. Rohani
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Department of Infectious Diseases, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
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Nguyen D, Ionides EL. A second-order iterated smoothing algorithm. STATISTICS AND COMPUTING 2017; 27:1677-1692. [PMID: 28860681 PMCID: PMC5573285 DOI: 10.1007/s11222-016-9711-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/03/2016] [Indexed: 06/07/2023]
Abstract
Simulation-based inference for partially observed stochastic dynamic models is currently receiving much attention due to the fact that direct computation of the likelihood is not possible in many practical situations. Iterated filtering methodologies enable maximization of the likelihood function using simulation-based sequential Monte Carlo filters. Doucet et al. (2013) developed an approximation for the first and second derivatives of the log likelihood via simulation-based sequential Monte Carlo smoothing and proved that the approximation has some attractive theoretical properties. We investigated an iterated smoothing algorithm carrying out likelihood maximization using these derivative approximations. Further, we developed a new iterated smoothing algorithm, using a modification of these derivative estimates, for which we establish both theoretical results and effective practical performance. On benchmark computational challenges, this method beat the first-order iterated filtering algorithm. The method's performance was comparable to a recently developed iterated filtering algorithm based on an iterated Bayes map. Our iterated smoothing algorithm and its theoretical justification provide new directions for future developments in simulation-based inference for latent variable models such as partially observed Markov process models.
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Affiliation(s)
- Dao Nguyen
- Department of Statistics, University of Michigan, Ann Arbor, MI, USA
| | - Edward L. Ionides
- Department of Statistics, University of Michigan, Ann Arbor, MI, USA
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Effects of reactive social distancing on the 1918 influenza pandemic. PLoS One 2017; 12:e0180545. [PMID: 28704460 PMCID: PMC5507503 DOI: 10.1371/journal.pone.0180545] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 06/16/2017] [Indexed: 11/19/2022] Open
Abstract
The 1918 influenza pandemic was characterized by multiple epidemic waves. We investigated reactive social distancing, a form of behavioral response where individuals avoid potentially infectious contacts in response to available information on an ongoing epidemic or pandemic. We modelled its effects on the three influenza waves in the United Kingdom. In previous studies, human behavioral response was modelled by a Power function of the proportion of recent influenza mortality in a population, and by a Hill function, which is a function of the number of recent influenza mortality. Using a simple epidemic model with a Power function and one common set of parameters, we provided a good model fit for the observed multiple epidemic waves in London boroughs, Birmingham and Liverpool. We further applied the model parameters from these three cities to all 334 administrative units in England and Wales and including the population sizes of individual administrative units. We computed the Pearson's correlation between the observed and simulated for each administrative unit. We found a median correlation of 0.636, indicating that our model predictions are performing reasonably well. Our modelling approach is an improvement from previous studies where separate models are fitted to each city. With the reduced number of model parameters used, we achieved computational efficiency gain without over-fitting the model. We also showed the importance of reactive behavioral distancing as a potential non-pharmaceutical intervention during an influenza pandemic. Our work has both scientific and public health significance.
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Domenech de Cellès M, Magpantay FMG, King AA, Rohani P. The pertussis enigma: reconciling epidemiology, immunology and evolution. Proc Biol Sci 2016; 283:rspb.2015.2309. [PMID: 26763701 DOI: 10.1098/rspb.2015.2309] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pertussis, a highly contagious respiratory infection, remains a public health priority despite the availability of vaccines for 70 years. Still a leading cause of mortality in developing countries, pertussis has re-emerged in several developed countries with high vaccination coverage. Resurgence of pertussis in these countries has routinely been attributed to increased awareness of the disease, imperfect vaccinal protection or high infection rates in adults. In this review, we first present 1980-2012 incidence data from 63 countries and show that pertussis resurgence is not universal. We further argue that the large geographical variation in trends probably precludes a simple explanation, such as the transition from whole-cell to acellular pertussis vaccines. Reviewing available evidence, we then propose that prevailing views on pertussis epidemiology are inconsistent with both historical and contemporary data. Indeed, we summarize epidemiological evidence showing that natural infection and vaccination both appear to provide long-term protection against transmission and disease, so that previously infected or vaccinated adults contribute little to overall transmission at a population level. Finally, we identify several promising avenues that may lead to a consistent explanation of global pertussis epidemiology and to more effective control strategies.
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Affiliation(s)
| | - Felicia M G Magpantay
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Aaron A King
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA Department of Mathematics, University of Michigan, Ann Arbor, MI 48109, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pejman Rohani
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA Odum School of Ecology, University of Georgia, Athens, GA 30602, USA College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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12
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MAGPANTAY FMG, DE CELLÉS MDOMENECH, ROHANI P, KING AA. Pertussis immunity and epidemiology: mode and duration of vaccine-induced immunity. Parasitology 2016; 143:835-849. [PMID: 26337864 PMCID: PMC4792787 DOI: 10.1017/s0031182015000979] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The resurgence of pertussis in some countries that maintain high vaccination coverage has drawn attention to gaps in our understanding of the epidemiological effects of pertussis vaccines. In particular, major questions surround the nature, degree and durability of vaccine protection. To address these questions, we used mechanistic transmission models to examine regional time series incidence data from Italy in the period immediately following the introduction of acellular pertussis (aP) vaccine. Our results concur with recent animal-challenge experiments wherein infections in aP-vaccinated individuals proved as transmissible as those in naive individuals but much less symptomatic. On the other hand, the data provide evidence for vaccine-driven reduction in susceptibility, which we quantify via a synthetic measure of vaccine impact. As to the precise nature of vaccine failure, the data do not allow us to distinguish between leakiness and waning of vaccine immunity, or some combination of these. Across the range of well-supported models, the nature and duration of vaccine protection, the age profile of incidence and the range of projected epidemiological futures differ substantially, underscoring the importance of the remaining unknowns. We identify key data gaps: sources of data that can supply the information needed to eliminate these remaining uncertainties.
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Affiliation(s)
- F. M. G. MAGPANTAY
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - M. DOMENECH DE CELLÉS
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - P. ROHANI
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - A. A. KING
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Mathematics, University of Michigan, Ann Arbor, MI 48109, USA
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McDonald SA, Teunis P, van der Maas N, de Greeff S, de Melker H, Kretzschmar ME. An evidence synthesis approach to estimating the incidence of symptomatic pertussis infection in the Netherlands, 2005-2011. BMC Infect Dis 2015; 15:588. [PMID: 26715486 PMCID: PMC4696101 DOI: 10.1186/s12879-015-1324-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/12/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite high vaccination coverage, infection with Bordetella pertussis is a current public health concern in the Netherlands and other European Union member states. Because surveillance data are subject to extensive under-ascertainment and under-reporting, incidence is difficult to determine. Our objective was to estimate the age-group specific incidence of symptomatic pertussis infection in the Netherlands over the period 2005-2011, using multi-parameter evidence synthesis. METHODS Age-specific seroconversion probabilities were estimated for 2007 using Netherlands population data stratified by age-group and cross-sectional population-wide serosurvey (PIENTER-2) data, with a sero-diagnostic cut-off of 125 EU/ml as a proxy for recent infection. Symptomatic probabilities were derived from a study of household contacts and from PIENTER-2. The annual number of symptomatic infected (SI) persons was estimated using evidence synthesis methods in a Bayesian framework, by combining the estimated incidence of infection with notification data and symptomatic probabilities. RESULTS An incidence rate of 128 SI cases per 10,000 population (95 % credible interval [CrI]: 110-150) was estimated for 2005, which decreased to 107 per 10,000 (95 % CrI: 91-126) for 2011. The degree of underestimation in statutory notified cases was age-dependent, ranging from 10-fold (10-19 years) to 69-fold (60+ years). The largest annual decreases in SI incidence rate over the study period were in the 1-4 and 5-9 years age-groups (24.3 %, 15.9 % per year, respectively). CONCLUSIONS By synthesising all available data, the incidence of symptomatic pertussis and the extent to which SI is underrepresented by notification data can be estimated. Such estimates are essential for disease burden computation and for informing public health priority-setting.
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Affiliation(s)
- Scott A McDonald
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
| | - Peter Teunis
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
| | - Nicoline van der Maas
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
| | - Sabine de Greeff
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
| | - Hester de Melker
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
| | - Mirjam E Kretzschmar
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands.
- Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, PO Box 85500, 3508 GA, Utrecht, Netherlands.
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14
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Morris SE, Pitzer VE, Viboud C, Metcalf CJE, Bjørnstad ON, Grenfell BT. Demographic buffering: titrating the effects of birth rate and imperfect immunity on epidemic dynamics. J R Soc Interface 2015; 12:20141245. [PMID: 25589567 PMCID: PMC4345488 DOI: 10.1098/rsif.2014.1245] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Host demography can alter the dynamics of infectious disease. In the case of perfectly immunizing infections, observations of strong sensitivity to demographic variation have been mechanistically explained through analysis of the susceptible–infected–recovered (SIR) model that assumes lifelong immunity following recovery from infection. When imperfect immunity is incorporated into this framework via the susceptible–infected–recovered–susceptible (SIRS) model, with individuals regaining full susceptibility following recovery, we show that rapid loss of immunity is predicted to buffer populations against the effects of demographic change. However, this buffering is contrary to the dependence on demography recently observed for partially immunizing infections such as rotavirus and respiratory syncytial virus. We show that this discrepancy arises from a key simplification embedded in the SIR(S) framework, namely that the potential for differential immune responses to repeat exposures is ignored. We explore the minimum additional immunological information that must be included to reflect the range of observed dependencies on demography. We show that including partial protection and lower transmission following primary infection is sufficient to capture more realistic reduced levels of buffering, in addition to changes in epidemic timing, across a range of partially and fully immunizing infections. Furthermore, our results identify key variables in this relationship, including R0.
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Affiliation(s)
- Sinead E Morris
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Cécile Viboud
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Ottar N Bjørnstad
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA Center for Infectious Disease Dynamics, Department of Entomology, Pennsylvania State University, University Park, PA, USA Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Bryan T Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
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15
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Combating pertussis resurgence: One booster vaccination schedule does not fit all. Proc Natl Acad Sci U S A 2015; 112:E472-7. [PMID: 25605878 DOI: 10.1073/pnas.1415573112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pertussis has reemerged as a major public health concern in many countries where it was once considered well controlled. Although the mechanisms responsible for continued pertussis circulation and resurgence remain elusive and contentious, many countries have nevertheless recommended booster vaccinations, the timing and number of which vary widely. Here, using a stochastic, age-stratified transmission model, we searched for cost-effective booster vaccination strategies using a genetic algorithm. We did so assuming four hypothesized mechanisms underpinning contemporary pertussis epidemiology: (I) insufficient coverage, (II) frequent primary vaccine failure, (III) waning of vaccine-derived protection, and (IV) vaccine "leakiness." For scenarios I-IV, successful booster strategies were identified and varied considerably by mechanism. Especially notable is the inability of booster schedules to alleviate resurgence when vaccines are leaky. Critically, our findings argue that the ultimate effectiveness of vaccine booster schedules will likely depend on correctly pinpointing the causes of resurgence, with misdiagnosis of the problem epidemiologically ineffective and economically costly.
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