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Rocha Filho TM, Mendes JFF, Murari TB, Nascimento Filho AS, Cordeiro AJA, Ramalho WM, Scorza FA, Almeida ACG, Moret MA. Optimization of COVID-19 vaccination and the role of individuals with a high number of contacts: A model based approach. PLoS One 2022; 17:e0262433. [PMID: 35259169 PMCID: PMC8903293 DOI: 10.1371/journal.pone.0262433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/24/2021] [Indexed: 01/24/2023] Open
Abstract
We report strong evidence of the importance of contact hubs (or superspreaders) in mitigating the current COVID-19 pandemic. Contact hubs have a much larger number of contacts than the average in the population, and play a key role on the effectiveness of vaccination strategies. By using an age-structures compartmental SEIAHRV (Susceptible, Exposed, Infected symptomatic, Asymptomatic, Hospitalized, Recovered, Vaccinated) model, calibrated from available demographic and COVID-19 incidence, and considering separately those individuals with a much greater number of contacts than the average in the population, we show that carefully choosing who will compose the first group to be vaccinated can impact positively the total death toll and the demand for health services. This is even more relevant in countries with a lack of basic resources for proper vaccination and a significant reduction in social isolation. In order to demonstrate our approach we show the effect of hypothetical vaccination scenarios in two countries of very different scales and mitigation policies, Brazil and Portugal.
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Affiliation(s)
- Tarcísio M. Rocha Filho
- International Center for Condensed Matter Physics, Universidade de Brasília, Brasília, DF, Brazil
- Instituto de Física, Universidade de Brasília, Brasília, DF, Brazil
- * E-mail:
| | - José F. F. Mendes
- Departamento de Física & I3N, Universidade de Aveiro, Aveiro, Portugal
| | | | | | - Antônio J. A. Cordeiro
- Centro Universitário SENAI CIMATEC, Salvador, BA, Brazil
- Instituto Federal de Educação e Tecnologia da Bahia, Feira de Santana, BA, Brazil
| | - Walter M. Ramalho
- FCE and Núcleo de Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil
| | - Fúlvio A. Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina/Universidade Federal de São Paulo (EPM/UNIFESP), São Paulo, SP, Brazil
| | | | - Marcelo A. Moret
- Centro Universitário SENAI CIMATEC, Salvador, BA, Brazil
- Universidade do Estado da Bahia, Salvador, BA, Brazil
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Williams JR, Manfredi P, Melegaro A. The potential impact of the demographic transition in the Senegal-Gambia region of sub-Saharan Africa on the burden of infectious disease and its potential synergies with control programmes: the case of hepatitis B. BMC Med 2018; 16:118. [PMID: 30041645 PMCID: PMC6058373 DOI: 10.1186/s12916-018-1100-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/14/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Sub-Saharan Africa (SSA) continues to suffer high communicable disease burdens as its demographic transition (DT) proceeds. Although the consequent changes in population structures influence age-specific contact patterns relevant for transmission, the age distribution of immunity, and the disease burden, investigation of the potential of DT to affect infectious disease epidemiology in regions of SSA has hitherto been overlooked. With a substantial disease burden and complex epidemiology, hepatitis B virus (HBV) represents a prime example of an infection whose epidemiology may be significantly influenced by the DT. METHODS An age-structured mathematical model for HBV in the Senegal and Gambia (SG) region was set within a demographic framework with varying vital rates mirroring the entire course of the DT there over 1850-2100, to investigate the effects of the DT on HBV epidemiology, with and without the combined action of vaccination. The model was run from its reconstructed ancien régime (old order) demo-epidemiologic equilibrium and calibrated against SG 1950 age-distribution estimates and Gambian pre-vaccination HBV age-prevalence data. RESULTS The model, which reproduced well demographic and HBV age-prevalence data, predicted a complex transition of HBV epidemiology over the course of the DT. This included a prolonged epoch of expansion alongside population growth and rejuvenation until 1990-2000, followed by a dramatic retreat, mainly reflecting projected fertility decline during the twenty-first century. This transitional pattern was mostly explained by the underlying demographically driven changes in horizontal transmission resulting from the changes in the age structure of the population. During 2000-2150 the HBV burden is predicted to decline by more than 70% even in the absence of vaccination. CONCLUSIONS Demographic change alone may strongly affect HBV disease burden and shape HBV endemicity. The onset of the demographically driven decline in HBV prevalence, aligned with the expansion of HBV vaccination, forms a synergy potentially boosting effectiveness of control. Such a synergy currently appears to be presenting a "window of opportunity" facilitating HBV elimination which it would be important to exploit and which underlines the importance of taking demographic change into account when assessing the potential longer term impact of vaccination and other control measures.
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Affiliation(s)
- John R Williams
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London, W2 1PG, UK.
| | - Piero Manfredi
- Dipartimento di Economia e Management, University of Pisa, via Ridolfi 10, 56124, Pisa, Italy
| | - Alessia Melegaro
- Dondena Centre for Research on Social Dynamics and Public Policy and Department of Social and Political Science, Bocconi University, Via Roentgen 1, 20136, Milan, Italy
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Gallone MS, Gallone MF, Larocca AMV, Germinario C, Tafuri S. Lack of immunity against rubella among Italian young adults. BMC Infect Dis 2017; 17:199. [PMID: 28270106 PMCID: PMC5341462 DOI: 10.1186/s12879-017-2295-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 02/28/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To support the evaluation of the 2010-15 National Plan for Measles and Congenital Rubella Elimination, the authors designed and performed a serosurveillance survey to verify the immunity/susceptibility rate against rubella among Apulian young adults. METHODS The study was carried out from May 2011 to June 2012 in the Department of Transfusion Medicine/Blood Bank of Policlinico General Hospital in Bari. Subjects were enrolled by a convenience sampling. For each enrolled patient a 5 ml serum sample was collected and tested for anti-rubella IgG. The geometrical means (GMT) of anti-rubella IgG was calculated. T student test or ANOVA test, when appropriate, was used to compare the means of age per gender and GMT of anti-rubella IgG titres per age classes. Chi-square test was used to compare the proportion of anti-rubella IgG positive subjects per gender and per age classes. For all tests, a p value <0.05 was considered as significant. RESULTS At the end of the study 1764 subjects were enrolled, 1362 (77.2%) of which were male. The mean age was 38.4 ± 11.7 years (range: 17-65). 86.7% (95% CI = 85.0-88.2) had a positive titre of anti-rubella IgG. GMT of anti-rubella IgG titre was 4.3. The proportion of positive subjects was of 76.8% (n = 279/363; 95% CI = 72.2-81.1) in persons aged 18-26 years; 88.1% (n = 310/352; 95% CI = 84.2-91.3) in 27-35 year-old people; 88.5% (n = 464/524; 95% CI = 85.5-91.1) in 36-45 year-old people; 90.7% (n = 350/386; 95% CI = 87.3-93.4) among people aged 46-55 years and 90.6% (n = 126/139; 95% CI = 84.5-94.9) in 55-65 year-old people (Chi-square = 39.7; p < 0.0001). GMT of anti-rubella IgG titre was 4.3 (4.3 in male and 4.2 in female, t = 2.2; p = 0.03) and seems to differ dividing the enrolled subjects by age group (F = 14.3; p < 0.0001). CONCLUSIONS According to our data, too many women of child-bearing age are still unprotected from rubella in the elimination era and in this scenario the public health efforts should be oriented to catch-up activities.
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Affiliation(s)
- Maria Serena Gallone
- Department of Biomedical Science and Human Oncology, University of Bari Aldo Moro, Piazza Giulio Cesare 11, 70124, Bari, Italy.
| | - Maria Filomena Gallone
- Department of Biomedical Science and Human Oncology, University of Bari Aldo Moro, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | | | - Cinzia Germinario
- Department of Biomedical Science and Human Oncology, University of Bari Aldo Moro, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | - Silvio Tafuri
- Department of Biomedical Science and Human Oncology, University of Bari Aldo Moro, Piazza Giulio Cesare 11, 70124, Bari, Italy
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Thompson KM. Evolution and Use of Dynamic Transmission Models for Measles and Rubella Risk and Policy Analysis. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2016; 36:1383-1403. [PMID: 27277138 DOI: 10.1111/risa.12637] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The devastation caused by periodic measles outbreaks motivated efforts over more than a century to mathematically model measles disease and transmission. Following the identification of rubella, which similarly presents with fever and rash and causes congenital rubella syndrome (CRS) in infants born to women first infected with rubella early in pregnancy, modelers also began to characterize rubella disease and transmission. Despite the relatively large literature, no comprehensive review to date provides an overview of dynamic transmission models for measles and rubella developed to support risk and policy analysis. This systematic review of the literature identifies quantitative measles and/or rubella dynamic transmission models and characterizes key insights relevant for prospective modeling efforts. Overall, measles and rubella represent some of the relatively simplest viruses to model due to their ability to impact only humans and the apparent life-long immunity that follows survival of infection and/or protection by vaccination, although complexities arise due to maternal antibodies and heterogeneity in mixing and some models considered potential waning immunity and reinfection. This review finds significant underreporting of measles and rubella infections and widespread recognition of the importance of achieving and maintaining high population immunity to stop and prevent measles and rubella transmission. The significantly lower transmissibility of rubella compared to measles implies that all countries could eliminate rubella and CRS by using combination of measles- and rubella-containing vaccines (MRCVs) as they strive to meet regional measles elimination goals, which leads to the recommendation of changing the formulation of national measles-containing vaccines from measles only to MRCV as the standard of care.
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Maitani Y, Ishikawa H. Effectiveness assessment of vaccination policy against measles epidemic in Japan using an age-time two-dimensional mathematical model. Environ Health Prev Med 2011; 17:34-43. [PMID: 21553196 DOI: 10.1007/s12199-011-0217-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 04/08/2011] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES In 2007, measles prevailed among the youth and young adult population in Japan, creating in a serious social problem. Among the developed countries, Japan has a relatively high incidence of measles. The objective of this study was to assess the effect of improvements in the vaccination policy against measles through simulations. METHODS We developed an age-time two-dimensional model for the transmission of measles to reflect an age structure, enabling contact rate to be selected by age. Introduction of the maternal immunity class into the model allowed natural infection and vaccination to be discriminated along the course of an infant's mother acquiring the immunity, thereby resulting in an improved accuracy of the simulations in infants. Several vaccination scenarios were attempted in order to assess the influence of various vaccination policies on the prevention of a measles epidemic. RESULTS The results of this quantitative study indicated that suppression of a measles outbreak requires the maintenance of high vaccine coverage and that a decline in vaccine coverage may result in a measles epidemic. CONCLUSIONS The present standard immunization program for measles will maintain an acceptable level of immunity and is therefore associated with a low risk of an epidemic after discontinuation of the third and fourth stages as scheduled--as long as at least 90% vaccine coverage of the first and second is maintained. The simulation results show that discontinuation of the third and fourth stages of vaccination as scheduled should be accompanied by endeavors to maintain appropriate high vaccine coverage of the first and second stages.
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Affiliation(s)
- Yusuke Maitani
- Department of Human Ecology, Graduate School of Environmental Science, Okayama University, Okayama, 700-8530, Japan
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Threshold behaviour of a SIR epidemic model with age structure and immigration. J Math Biol 2007; 57:1-27. [DOI: 10.1007/s00285-007-0143-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 10/03/2007] [Indexed: 10/22/2022]
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Chironna M, Prato R, Sallustio A, Martinelli D, Germinario C, Lopalco P, Quarto M. Genetic characterization of measles virus strains isolated during an epidemic cluster in Puglia, Italy 2006-2007. Virol J 2007; 4:90. [PMID: 17888162 PMCID: PMC2039735 DOI: 10.1186/1743-422x-4-90] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 09/21/2007] [Indexed: 05/17/2023] Open
Abstract
The genetic characterization of wild-type measles strains isolated during an epidemic cluster of measles occurred in Puglia (South Italy), between November 2006 and January 2007, was performed. Measles virus (MV) detection was carried out by a nested RT-PCR on 8 of 18 total cases. The viruses were analyzed using the standard genotyping protocols. The N gene sequences of the strains from outbreak were identical to each other, and sequence analysis revealed that the viruses belonged to genotype B3, subgroup B3.1, never identified before in Italy. An importation of measles B3.1 strains from Africa was hypothesized. Molecular surveillance will help to monitor the progress in measles elimination.
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Affiliation(s)
- Maria Chironna
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
- Osservatorio Epidemiologico Regione Puglia, Coordinating Centre for Notifiable Diseases, Bari, Italy
| | - Rosa Prato
- Dipartimento di Scienze Mediche e del Lavoro, Hygiene Section, University of Foggia, Italy
- Osservatorio Epidemiologico Regione Puglia, Coordinating Centre for Notifiable Diseases, Bari, Italy
| | - Anna Sallustio
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
| | - Domenico Martinelli
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
- Osservatorio Epidemiologico Regione Puglia, Coordinating Centre for Notifiable Diseases, Bari, Italy
| | - Cinzia Germinario
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
- Osservatorio Epidemiologico Regione Puglia, Coordinating Centre for Notifiable Diseases, Bari, Italy
| | - Pierluigi Lopalco
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Michele Quarto
- Hygiene Section, Department of Biomedical Sciences and Human Oncology, University of Bari, Policlinico Piazza G. Cesare 11, 70124 Bari, Italy
- Osservatorio Epidemiologico Regione Puglia, Coordinating Centre for Notifiable Diseases, Bari, Italy
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Bonanni P, Bechini A, Boccalini S, Peruzzi M, Tiscione E, Boncompagni G, Mannelli F, Salmaso S, Filia A, Ciofi degli Atti M. Progress in Italy in control and elimination of measles and congenital rubella. Vaccine 2007; 25:3105-10. [PMID: 17306425 DOI: 10.1016/j.vaccine.2007.01.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
After a long period of inadequate vaccination coverage, Italy implemented a National Elimination Plan for Measles and Congenital Rubella in 2003, in order to reach the objective by 2010, according to the goals of World Health Organization (WHO) in the European Region. Concerted efforts have been made in the last years in all Italian Regions, leading to substantial increase of coverage both at 24 months of age and in older children, also thanks to a special campaign addressed to school-age subjects. Measles and rubella are at historical lows, although several limited outbreaks occurred in 2006. However, such outbreaks gave the opportunity to show that lab surveillance of cases, identification of contacts and their rapid immunisation are feasible and able to stop further spread of infection. The re-introduction in 2005 of compulsory notification for congenital rubella and rubella during pregnancy has a key role in the evaluation of needs for women at fertile age and to address efforts of vaccination to risk groups, like immigrant women. Although further actions need to be pursued, the increase of vaccination coverage and the strong commitment of the Italian public health service in the Elimination Plan suggest that phase II of measles control is approaching and that final elimination of measles and congenital rubella can be reached in Italy.
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Affiliation(s)
- Paolo Bonanni
- Department of Public Health, University of Florence, Italy. <
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CHEN S, CHANG C, JOU L, LIAO C. Modelling vaccination programmes against measles in Taiwan. Epidemiol Infect 2006; 135:775-86. [PMID: 17064459 PMCID: PMC2870623 DOI: 10.1017/s0950268806007369] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Vaccination has proved a powerful defence against measles. We reappraise measles seroepidemiological data in Taiwan from 1974 to 2004 having robust age-stratified serological information on exposure and immunity to quantitatively characterize measles vaccination programmes. We dynamically model measles seroepidemiology to estimate age-dependent intensity of infection associated with the effects of different contact patterns on pre- and post-vaccination. The WAIFM (who acquires infection from whom) contact matrix is employed to describe the transmission between and within each age group. A deterministic SEIR (susceptible-exposed-infected-recovery) model is used to capture subpopulation dynamics. Our study shows that mass regional or nationwide vaccination programmes could greatly reduce the potential for a major measles epidemic and have strong direct effects on the potential impact of childhood vaccination. We parameterize a predictive model that should reduce the socio-economic costs of measles surveillance in Taiwan and thereby encourage its continuance, especially for preschool children.
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Affiliation(s)
- S. C. CHEN
- Ecotoxicological Modelling Centre, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan, ROC
| | - C. F. CHANG
- Ecotoxicological Modelling Centre, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan, ROC
| | - L. J. JOU
- Ecotoxicological Modelling Centre, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan, ROC
- Department of Biomechatronic Engineering, National Ilan University, Ilan, Taiwan, ROC
| | - C. M. LIAO
- Ecotoxicological Modelling Centre, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan, ROC
- Corresponding author: Dr C. M. Liao, Ecotoxicological Modelling Centre, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan 10617, ROC. ()
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