scholarly journals Targeting vaccination against novel infections: risk, age and spatial structure for pandemic influenza in Great Britain

2010 ◽  
Vol 8 (58) ◽  
pp. 661-670 ◽  
Author(s):  
Matt J. Keeling ◽  
Peter J. White
Keyword(s):  
Age Groups ◽  
Risk Groups ◽  
H1n1 Influenza ◽  
Primary Concern ◽  
H1n1 Influenza Virus ◽  
Optimal Deployment ◽  
Age Structured ◽  
Vaccination Campaigns ◽  
The Impact ◽  
Simple Models

The emergence of a novel strain of H1N1 influenza virus in Mexico in 2009, and its subsequent worldwide spread, has focused attention to the question of optimal deployment of mass vaccination campaigns. Here, we use three relatively simple models to address three issues of primary concern in the targeting of any vaccine. The advantages of such simple models are that the underlying assumptions and effects of individual parameters are relatively clear, and the impact of uncertainty in the parametrization can be readily assessed in the early stages of an outbreak. In particular, we examine whether targeting risk-groups, age-groups or spatial regions could be optimal in terms of reducing the predicted number of cases or severe effects; and how these targeted strategies vary as the epidemic progresses. We examine the conditions under which it is optimal to initially target vaccination towards those individuals within the population who are most at risk of severe effects of infection. Using age-structured mixing matrices, we show that targeting vaccination towards the more epidemiologically important age groups (5–14 year olds and then 15–24 year olds) leads to the greatest reduction in the epidemic growth and hence reduces the total number of cases. Finally, we consider how spatially targeting the vaccine towards regions of country worst affected could provide an advantage. We discuss how all three of these priorities change as both the speed at which vaccination can be deployed and the start of the vaccination programme is varied.

scholarly journals Evaluating COVID-19 booster vaccination strategies in a partially vaccinated population: a modeling study.

2021 ◽  
Author(s):  
Clement R Massonnaud ◽  
Jonathan Roux ◽  
Vittoria Colizza ◽  
Pascal Crepey
Keyword(s):  
Age Groups ◽  
Booster Vaccination ◽  
Primary Vaccination ◽  
Morbidity And Mortality ◽  
Vaccination Strategies ◽  
Admission Data ◽  
Younger Age ◽  
Age Structured ◽  
Vaccination Campaigns ◽  
The Impact

Background. As evidence shows that vaccine immunity to COVID-19 wanes with time and decreases due to variants, several countries are implementing booster vaccination campaigns. The objective of this study was to analyze the morbidity and mortality burdens of different primary and booster vaccination strategies against COVID-19, using France as a case study. Methods. We used a deterministic, age-structured, compartmental model fitted to hospital admission data and validated against sero-prevalence data in France to analyze the impact of primary and booster vaccination strategies on morbidity and mortality assuming waning of immunity and increased virus transmissibility during winter. Findings. Strategies prioritizing primary vaccinations were systematically more effective than strategies prioritizing boosters. Regarding booster strategies targeting different age groups, their effectiveness varied with the levels of virus transmissibility, and according to the assumed loss of immunity for each age group. If the immunity reduction affects all age groups, people aged 30 to 49 years should be boosted in priority, even for low transmissibility levels. If the immunity reduction is restricted to people older than 65 years, boosting younger people becomes effective only above certain levels of transmissibility. Interpretation. Increasing the primary vaccination coverage should remain a priority to reduce morbidity and mortality due to COVID-19. If a plateau of primary vaccination has been reached, boosting immunity in younger age-groups could prevent more hospitalizations and deaths than boosting the immunity of older people, especially under conditions increasing SARS-CoV-2 transmissibility, or when facing new variants. Funding. The study was partially funded by the French national research agency through project SPHINX-17-CE36-0008-0.

scholarly journals Modelling the impact of extended vaccination strategies on the epidemiology of pertussis

2011 ◽  
Vol 140 (8) ◽  
pp. 1503-1514 ◽  
Author(s):  
M. H. ROZENBAUM ◽  
R. De VRIES ◽  
H. H. LE ◽  
M. J. POSTMA
Keyword(s):  
Booster Dose ◽  
Deterministic Model ◽  
Natural Infection ◽  
Age Groups ◽  
Vaccination Strategy ◽  
Booster Vaccination ◽  
Sensitivity Analyses ◽  
Wide Range ◽  
Age Structured ◽  
The Impact

SUMMARYThe aim of this study was to investigate the optimal pertussis booster vaccination strategy for The Netherlands. A realistic age-structured deterministic model was designed. Assuming a steady-state situation and correcting for underreporting, the model was calibrated using notification data from the period 1996–2000. Several sensitivity analyses were performed to explore the impact of different assumptions for parameters surrounded by uncertainty (e.g. duration of protection after natural infection, underreporting factors, and transmission probabilities). The optimal age of an additional booster dose is in the range of 10–15 years, and implementation of this booster dose will reduce both symptomatic and asymptomatic infections, although the incidence of symptomatic infections in older age groups will increase. The impact of the different assumptions used in the model was in general limited. We conclude that over a wide range of assumptions, an additional booster dose can reduce the incidence of pertussis in the population.

scholarly journals Contact surveys reveal heterogeneities in age-group contributions to SARS-CoV-2 dynamics in the United States

2021 ◽  
Author(s):  
Taylor Chin ◽  
Dennis M. Feehan ◽  
Caroline O. Buckee ◽  
Ayesha S. Mahmud
Keyword(s):  
United States ◽  
Age Groups ◽  
The United States ◽  
Contact Rate ◽  
Age Group ◽  
Contact Rates ◽  
Contact Patterns ◽  
Age Structured ◽  
The Impact ◽  
Over Time

SARS-CoV-2 is spread primarily through person-to-person contacts. Quantifying population contact rates is important for understanding the impact of physical distancing policies and for modeling COVID-19, but contact patterns have changed substantially over time due to shifting policies and behaviors. There are surprisingly few empirical estimates of age-structured contact rates in the United States both before and throughout the COVID-19 pandemic that capture these changes. Here, we use data from six waves of the Berkeley Interpersonal Contact Survey (BICS), which collected detailed contact data between March 22, 2020 and February 15, 2021 across six metropolitan designated market areas (DMA) in the United States. Contact rates were low across all six DMAs at the start of the pandemic. We find steady increases in the mean and median number of contacts across these localities over time, as well as a greater proportion of respondents reporting a high number of contacts. We also find that young adults between ages 18 and 34 reported more contacts on average compared to other age groups. The 65 and older age group consistently reported low levels of contact throughout the study period. To understand the impact of these changing contact patterns, we simulate COVID-19 dynamics in each DMA using an age-structured mechanistic model. We compare results from models that use BICS contact rate estimates versus commonly used alternative contact rate sources. We find that simulations parameterized with BICS estimates give insight into time-varying changes in relative incidence by age group that are not captured in the absence of these frequently updated estimates. We also find that simulation results based on BICS estimates closely match observed data on the age distribution of cases, and changes in these distributions over time. Together these findings highlight the role of different age groups in driving and sustaining SARS-CoV-2 transmission in the U.S. We also show the utility of repeated contact surveys in revealing heterogeneities in the epidemiology of COVID-19 across localities in the United States.

scholarly journals Impact of the COVID-19 Pandemic on the Intensity of Health Services Use in General Practice: A Retrospective Cohort Study

2021 ◽  
Vol 66 ◽  
Author(s):  
Yael Rachamin ◽  
Oliver Senn ◽  
Sven Streit ◽  
Julie Dubois ◽  
Michael J. Deml ◽  
...  
Keyword(s):  
General Practice ◽  
Health Services ◽  
Total Population ◽  
Age Groups ◽  
Risk Groups ◽  
Health Services Use ◽  
Care Needs ◽  
Hba1c Measurement ◽  
The Impact ◽  
Services Use

Objectives: We aimed to explore the impact of the Swiss shutdown in spring 2020 on the intensity of health services use in general practice.Methods: Based on an electronic medical records database, we built one patient cohort each for January-June 2019 (control, 173,523 patients) and 2020 (179,086 patients). We used linear regression to model weekly consultation counts and blood pressure (BP) and glycated hemoglobin (HbA1c) measurement counts per 100 patients and predicted non-shutdown values. Analyses were repeated for selected at-risk groups and different age groups.Results: During the shutdown, weekly consultation counts were lower than predicted by −17.2% (total population), −16.5% (patients with hypertension), −17.5% (diabetes), −17.6% (cardiovascular disease), −15.7% (patients aged <60 years), −20.4% (60–80 years), and −14.5% (>80 years). Weekly BP counts were reduced by −35.3% (total population) and −35.0% (hypertension), and HbA1c counts by −33.2% (total population) and −29.8% (diabetes). p-values <0.001 for all reported estimates.Conclusion: Our results document consequential decreases in consultation counts and chronic disease monitoring during the shutdown. It is crucial that health systems remain able to meet non-COVID-19-related health care needs.

scholarly journals Incidence, clinical features, and outcomes of COVID-19 in Canada: impact of sex and age

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jacob O’Brien ◽  
Kevin Y. Du ◽  
Chun Peng
Keyword(s):  
Incidence Rate ◽  
Age Groups ◽  
Case Fatality ◽  
Risk Groups ◽  
Older Age ◽  
Reproductive Age ◽  
Term Care ◽  
Severity Of The Disease ◽  
Lower Incidence Rate ◽  
The Impact

AbstractMale sex and older age have been reported to be associated with worse outcomes from COVID-19. It was postulated that estrogens may play a role in reducing the severity of the disease and may therefore offer a treatment option for COVID-19 patients. However, more female cases and deaths from COVID-19 have been recorded in Canada. To determine the potential role of estrogens, we analyzed COVID-19 data from Canada, focusing on the impact of sex and age. Although the overall incidence rate is higher in females than in males, when several high risk groups, including health care workers and long-term care residences, which are predominantly females, were excluded, we found that females had a lower incidence rate than males between the ages of 20s to 70s. Interestingly, this sex-based difference is more evident in females of the reproductive ages (20–49) than in postmenopausal patients (60s or older). Males have significantly higher hospitalization, ICU admission, and case fatality rates; however, a greater difference was observed in the older age groups. Finally, symptom manifestation varied between sexes. Some of the symptoms, which were more frequently observed in patients who recovered than patients who died, were more commonly observed in females of the reproductive age compared to their male counterparts. Since only females of the reproductive age have much higher circulating estrogens than males, these findings suggest that estrogens may play a role in reducing COVID-19 incidence and in the development of symptoms, especially those related to better survival.

scholarly journals Age-Structured Model for COVID-19: Effectiveness of Social Distancing and Contact Reduction

2020 ◽  
Author(s):  
Mark Kimathi ◽  
Samuel Mwalili ◽  
Viona Ojiambo ◽  
Duncan Gathungu
Keyword(s):  
Deterministic Model ◽  
Age Groups ◽  
School Closure ◽  
Model Parameters ◽  
Suitable Model ◽  
Age Group ◽  
Social Distancing ◽  
First Case ◽  
Age Structured ◽  
The Impact

Abstract Background: Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2. The disease has spread to almost every country in the world. Kenya reported its first case on 13th of March 2020. From 16th March 2020, the country instituted various social distancing strategies to reduce the transmission and flatten the epidemic curve. These strategies include school closure, dusk-to-dawn curfew, and travel restriction across counties, especially Nairobi, Mombasa and Kwale. An age-structured compartmental model was developed to assess the impact of non-pharmaceutical interventions on severity of infections, hospital demands and deaths. Methods: The population is divided into four age-groups and for each age-group there are seven compartments, namely: susceptible , exposed, asymptomatic, mild, severe, critical, death and recovered. The contact matrices between the different ages are integrated into an age-structured deterministic model via the force of infection. This model is represented by ordinary differential equations and solved using Runge–Kutta methods, with suitable model parameters. Simulation results for the unmitigated and mitigated scenarios were depicted, for the different age-groups. Results: The 45% reduction in contacts for 60-days period resulted to between 11.5-13% reduction of infections severity and deaths, while for the 190-days period yielded between 18.8-22.7% reduction. The peak of infections in the 60-days mitigation was higher and happened about 2 months after the relaxation of mitigation as compared to that of the 190-days mitigation, which happened just a month after mitigation were relaxed. Low numbers of cases in children under 15 years was attributed to low susceptibility of persons in this age-group. High numbers of cases are reported in the 15-29 years and 30-59 years age bands since these individuals have wider interaction spheres, and they form a significant percentage of Kenya population. Conclusion: Two mitigation periods, considered in the study, resulted to reductions in severe and critical cases, attack rates, hospital and ICU bed demands, as well as deaths, with the 190-days period giving higher reductions. The study revealed the age-dependency of the key health outputs.

scholarly journals Assessment of Social Distancing for Controlling COVID-19 in Korea: An Age-Structured Modeling Approach

2020 ◽  
Vol 17 (20) ◽  
pp. 7474
Author(s):  
Yongin Choi ◽  
James Slghee Kim ◽  
Heejin Choi ◽  
Hyojung Lee ◽  
Chang Hyeong Lee
Keyword(s):  
Mathematical Model ◽  
Age Groups ◽  
Epidemiological Data ◽  
The Elderly ◽  
Model Parameters ◽  
Social Distancing ◽  
First Case ◽  
Age Structured ◽  
Epidemiological Characteristics ◽  
The Impact

The outbreak of the novel coronavirus disease 2019 (COVID-19) occurred all over the world between 2019 and 2020. The first case of COVID-19 was reported in December 2019 in Wuhan, China. Since then, there have been more than 21 million incidences and 761 thousand casualties worldwide as of 16 August 2020. One of the epidemiological characteristics of COVID-19 is that its symptoms and fatality rates vary with the ages of the infected individuals. This study aims at assessing the impact of social distancing on the reduction of COVID-19 infected cases by constructing a mathematical model and using epidemiological data of incidences in Korea. We developed an age-structured mathematical model for describing the age-dependent dynamics of the spread of COVID-19 in Korea. We estimated the model parameters and computed the reproduction number using the actual epidemiological data reported from 1 February to 15 June 2020. We then divided the data into seven distinct periods depending on the intensity of social distancing implemented by the Korean government. By using a contact matrix to describe the contact patterns between ages, we investigated the potential effect of social distancing under various scenarios. We discovered that when the intensity of social distancing is reduced, the number of COVID-19 cases increases; the number of incidences among the age groups of people 60 and above increases significantly more than that of the age groups below the age of 60. This significant increase among the elderly groups poses a severe threat to public health because the incidence of severe cases and fatality rates of the elderly group are much higher than those of the younger groups. Therefore, it is necessary to maintain strict social distancing rules to reduce infected cases.

scholarly journals Differences in Pneumococcal Serotype Replacement in Individuals with and without Underlying Medical Conditions

2018 ◽  
Author(s):  
Daniel M. Weinberger ◽  
Joshua L Warren ◽  
Tine Dalby ◽  
Eugene D. Shapiro ◽  
Valentiner Branth ◽  
...  
Keyword(s):  
Age Groups ◽  
Risk Groups ◽  
Bayesian Regression ◽  
Childhood Vaccination ◽  
Conjugate Vaccines ◽  
Vaccine Serotypes ◽  
Serotype Replacement ◽  
Pneumococcal Serotype ◽  
Nationwide Surveillance ◽  
The Impact

ABSTRACTBackgroundPneumococcal conjugate vaccines (PCVs) have had a well-documented impact on the incidence of invasive pneumococcal disease (IPD) worldwide. However, declines in IPD due to vaccine-targeted serotypes have been partially offset by increases in IPD due to non-vaccine serotypes. The goal of this study was to quantify serotype-specific changes in the incidence of IPD that occurred in different age groups, with or without certain co-morbidities, following the introduction of PCV7 and PCV13 in the childhood vaccination program in Denmark.MethodsWe used nationwide surveillance data for IPD in Denmark and a hierarchical Bayesian regression framework to estimate changes in the incidence of IPD associated with the introduction of PCV7 (2007) and PCV13 (2010) while controlling for serotype-specific epidemic cycles and unrelated secular trends.Results and ConclusionsFollowing the introduction of PCV7 and 13 in children, the net impact of serotype replacement varied considerably by age group and the presence of comorbid conditions. Serotype replacement offset a greater fraction of the decline in vaccine-targeted serotypes following the introduction of PCV7 compared with the period following the introduction of PCV13. Differences in the magnitude of serotype replacement were due to variations in the incidence of non-vaccine serotypes in the different risk groups before the introduction of PCV7 and PCV13. The relative increases in the incidence of IPD caused by non-vaccine serotypes did not differ appreciably in the post-vaccination period. Serotype replacement offset a greater proportion of the benefit of PCVs in strata in which the non-vaccine serotypes comprised a larger proportion of cases prior to the introduction of the vaccines. These findings could help to predict the impact of next-generation conjugate vaccines in specific risk groups.

«Հայրենիքի պաշտպանի» և «մարդասպանի» անհատական հոգեբանական առանձնահատկությունները զինծառայողի ընկալման մեջ

2021 ◽  
pp. 221-227
Author(s):  
Mariam Karapetyan
Keyword(s):  
Quantitative Analysis ◽  
Age Groups ◽  
Risk Groups ◽  
Personality Types ◽  
Rorschach Test ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
Mental Problems ◽  
Previous Trauma ◽  
The Impact

The purpose of this article is to differentiate servicemen according to the character accentuation and to study the impact of war on their mental features. The objectives stemming from the purpose of the article is to study the age groups of the servicemen who took part in the hostilities, to identify the risk groups, to analyze the psychological tendencies of the «murderer» and the serviceman. The investigation uses a number of research methods: observation, qualitative and quantitative analysis of data and presentation, Rorschach test. In the course of the research, the following conclusions were made: war participants do not always pursue the same goal, war can be a means to satisfy their killing instinct or it can bring out a previous trauma and cause a killing pleasure. It is not necessary for the servicemen to have obvious mental problems to be considered murderers and not take part in hostilities. During the hostilities, people with different personality types are involved, which can leadto different traumas that can arise in different military situations.

scholarly journals Modeling the Interruption of the Transmission of Soil-Transmitted Helminths Infections in Kenya: Modeling Deworming, Water, and Sanitation Impacts

2021 ◽  
Vol 9 ◽  
Author(s):  
Collins Okoyo ◽  
Graham Medley ◽  
Charles Mwandawiro ◽  
Nelson Onyango
Keyword(s):  
Worm Burden ◽  
Age Groups ◽  
Drug Efficacy ◽  
Control Program ◽  
School Age Children ◽  
School Age ◽  
Regular Treatment ◽  
Soil Transmitted Helminths ◽  
Age Structured ◽  
The Impact

Kenya, just like other countries with endemic soil-transmitted helminths (STH), has conducted regular mass drug administration (MDA) program for the last 5 years among school aged children as a way to reduce STH infections burden in the country. However, the point of interruption of transmission of these infections still remains unclear. In this study, we developed and analyzed an age structured mathematical model to predict the elimination period (i.e., time taken to interrupt STH transmission) of these infections in Kenya. The study utilized a deterministic age structured model of the STH population dynamics under a regular treatment program. The model was applied to three main age groups: pre-school age children (2–4 years), school age children (5–14 years), and adult populations (≥15 years) and compared the impact of two interventions on worm burden and elimination period. The model-simulated results were compared with the 5 year field data from the Kenyan deworming program for all the three types of STH (Ascaris lumbricoides, Trichuris trichiura, and hookworm). The model demonstrated that the reduction of worm burden and elimination period depended heavily on four parameter groups; drug efficacy, number of treatment rounds, MDA and water, sanitation and hygiene (WASH) coverage. The analysis showed that for STH infections to be eliminated using MDA alone in a short time period, 3-monthly MDA plan is desired. However, complementation of MDA with WASH at an optimal (95%) coverage level was most effective. These results are important to the Kenyan STH control program as it will guide the recently launched Breaking Transmission Strategy.

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