scholarly journals Optimal Allocation of the Limited COVID-19 Vaccine Supply in South Korea

2021 ◽  
Vol 10 (4) ◽  
pp. 591
Author(s):  
Eunha Shim
Keyword(s):  
South Korea ◽  
Vaccine Efficacy ◽  
Optimal Allocation ◽  
Age Distribution ◽  
Case Fatality ◽  
Vaccination Strategy ◽  
Years Of Life Lost ◽  
Incidence And Mortality ◽  
Specific Contact ◽  
Epidemiological Characteristics

Initial supply of the coronavirus disease (COVID-19) vaccine may be limited, necessitating its effective use. Herein, an age-structured model of COVID-19 spread in South Korea is parameterized to understand the epidemiological characteristics of COVID-19. The model determines optimal vaccine allocation for minimizing infections, deaths, and years of life lost while accounting for population factors, such as country-specific age distribution and contact structure, and various levels of vaccine efficacy. A transmission-blocking vaccine should be prioritized in adults aged 20–49 years and those older than 50 years to minimize the cumulative incidence and mortality, respectively. A strategy to minimize years of life lost involves the vaccination of adults aged 40–69 years, reflecting the relatively high case-fatality rates and years of life lost in this age group. An incidence-minimizing vaccination strategy is highly sensitive to vaccine efficacy, and vaccines with lower efficacy should be administered to teenagers and adults aged 50–59 years. Consideration of age-specific contact rates and vaccine efficacy is critical to optimize vaccine allocation. New recommendations for COVID-19 vaccines under consideration by the Korean Centers for Disease Control and Prevention are mainly based on a mortality-minimizing allocation strategy.

scholarly journals COVID-19 Vaccine Prioritisation in Japan and South Korea

2021 ◽  
Author(s):  
June Young Chun ◽  
Hwichang Jeong ◽  
Philippe Beutels ◽  
Norio Ohmagari ◽  
Yongdai Kim ◽  
...  
Keyword(s):  
South Korea ◽  
Vaccine Efficacy ◽  
Optimal Allocation ◽  
Case Reports ◽  
Vaccination Strategy ◽  
Sensitivity Analyses ◽  
Allocation Strategy ◽  
Death Toll ◽  
Specific Contact ◽  
Bayesian Inference Method

Background Due to a limited initial supply of COVID-19 vaccines, the prioritisation of individuals for vaccination is of utmost importance for public health. Here, we provide the optimal allocation strategy for COVID-19 vaccines according to age in Japan and South Korea. Methods Combining national case reports, age-specific contact matrices, and observed periods between each stages of infection (Susceptible-Exposed-Infectious-Quarantined), we constructed a compartmental model. We estimated the age-stratified probability of transmission given contact (q_i) using Bayesian inference method and simulated different vaccination scenarios to reduce either case numbers or death toll. We also performed sensitivity analyses on the proportion of asymptomatic cases and vaccine efficacy. Findings The model inferred age-stratified probability of transmission given contact (q_i) showed similar age-dependent increase in Japan and South Korea. Assuming the reported COVID-19 vaccine efficacy, our results indicate that Japan and South Korea need to prioritise individuals aged 20-35 years and individuals aged over 60 years, respectively, to minimise case numbers. To minimise the death toll, both countries need to prioritise individuals aged over 75 years. These trends were not changed by proportions of asymptomatic cases and varying vaccine efficacy on individuals under 20 years. Interpretation We presented the optimal vaccination strategy for Japan and South Korea. Comparing the results of these countries demonstrates that not only the effective contact rates containing q_i but also the age-demographics of current epidemic in Japan (dominance in 20s) and South Korea (dominant cases over 50s) affect vaccine allocation strategy.

scholarly journals Enhanced comparisons of COVID-19 mortality across populations

2020 ◽  
Author(s):  
Chalapati Rao ◽  
Suhail A. Doi ◽  
Gail Williams
Keyword(s):  
Health System ◽  
Age Distribution ◽  
Case Fatality ◽  
The South ◽  
South Korean ◽  
Age Variations ◽  
Incidence And Mortality ◽  
System Factors ◽  
The Impact ◽  
Age Structures

AbstractBackgroundThe reported crude case fatality rate (CFR) for COVID-19 varies considerably across countries. Crude CFRs could by biased by larger proportions of older COVID-19 cases in population data, who are also at increased mortality risk. Such distorted age case structures are a common feature of selective COVID 19 testing strategies in many countries, and they potentially mask underlying differences arising from other important factors such as health system burden.MethodsWe used the method of direct case-age standardisation to evaluate the effects of age variations on CFRs. Data on cases and death by age from Italy, Spain, China, Australia and South Korea were analysed to derive standardised CFRs. Findings were compared across different case age distribution references as standards.ResultsUsing the South Korean case age distribution as a standard, the fivefold higher crude CFR for Italy is reduced to less than two-fold after adjustment, while the crude CFR difference for Spain is virtually eliminated. The adjusted CFR for Australia is the lowest among all countries.DiscussionMortality differences based on crude CFRs are exaggerated by age structures, which are effectively controlled by case age standardization. Residual CFR differences could be attributed to health and health system factors. The South Korean case age distribution is an appropriate reference standard, given its robust case detection and contact tracing program. Till reliable population level indicators of incidence and mortality are available, the age-standardized CFR could be a viable option for international comparison of the impact of the COVID 19 epidemic.SummaryThe knownThere are intense debates around the magnitude of and reasons for wide variations in observed case fatality rates (CFRs) from COVID 19 across countries. Age is commonly speculated as a reason, but this has not been technically quantified or explained.The newThe technique of direct standardization using reference distributions of case age structures eliminates the effects of age on CFR, thus enhancing the comparability as well as understanding of differentialsThe implicationsResidual differences between adjusted CFRs can be used to infer health and health system factors that influence mortality in COVID 19 cases in different populations

scholarly journals Dynamic prioritization of COVID-19 vaccines when social distancing is limited for essential workers

2021 ◽  
Vol 118 (16) ◽  
pp. e2025786118
Author(s):  
Jack H. Buckner ◽  
Gerardo Chowell ◽  
Michael R. Springborn
Keyword(s):  
Optimal Allocation ◽  
Rapid Development ◽  
Vaccination Campaign ◽  
The United States ◽  
Years Of Life Lost ◽  
Social Distancing ◽  
Health Goals ◽  
Temporal Flexibility ◽  
Nonpharmaceutical Interventions ◽  
Epidemiological Characteristics

COVID-19 vaccines have been authorized in multiple countries, and more are under rapid development. Careful design of a vaccine prioritization strategy across sociodemographic groups is a crucial public policy challenge given that 1) vaccine supply will be constrained for the first several months of the vaccination campaign, 2) there are stark differences in transmission and severity of impacts from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) across groups, and 3) SARS-CoV-2 differs markedly from previous pandemic viruses. We assess the optimal allocation of a limited vaccine supply in the United States across groups differentiated by age and essential worker status, which constrains opportunities for social distancing. We model transmission dynamics using a compartmental model parameterized to capture current understanding of the epidemiological characteristics of COVID-19, including key sources of group heterogeneity (susceptibility, severity, and contact rates). We investigate three alternative policy objectives (minimizing infections, years of life lost, or deaths) and model a dynamic strategy that evolves with the population epidemiological status. We find that this temporal flexibility contributes substantially to public health goals. Older essential workers are typically targeted first. However, depending on the objective, younger essential workers are prioritized to control spread or seniors to directly control mortality. When the objective is minimizing deaths, relative to an untargeted approach, prioritization averts deaths on a range between 20,000 (when nonpharmaceutical interventions are strong) and 300,000 (when these interventions are weak). We illustrate how optimal prioritization is sensitive to several factors, most notably, vaccine effectiveness and supply, rate of transmission, and the magnitude of initial infections.

scholarly journals Dynamic Prioritization of COVID-19 Vaccines When Social Distancing is Limited for Essential Workers

2020 ◽  
Author(s):  
Jack H. Buckner ◽  
Gerardo Chowell ◽  
Michael R. Springborn
Keyword(s):  
Optimal Allocation ◽  
Rapid Development ◽  
Vaccination Campaign ◽  
Years Of Life Lost ◽  
Social Distancing ◽  
Demographic Groups ◽  
Health Goals ◽  
Temporal Flexibility ◽  
Policy Objectives ◽  
Epidemiological Characteristics

AbstractCOVID-19 vaccines have been authorized in multiple countries and more are under rapid development. Careful design of a vaccine prioritization strategy across socio-demographic groups is a crucial public policy challenge given that (1) vaccine supply will be constrained for the first several months of the vaccination campaign, (2) there are stark differences in transmission and severity of impacts from SARS-CoV-2 across groups, and (3) SARS-CoV-2 differs markedly from previous pandemic viruses. We assess the optimal allocation of a limited vaccine supply in the U.S. across groups differentiated by age and also essential worker status, which constrains opportunities for social distancing. We model transmission dynamics using a compartmental model parameterized to capture current understanding of the epidemiological characteristics of COVID-19, including key sources of group heterogeneity (susceptibility, severity, and contact rates). We investigate three alternative policy objectives (minimizing infections, years of life lost, or deaths) and model a dynamic strategy that evolves with the population epidemiological status. We find that this temporal flexibility contributes substantially to public health goals. Older essential workers are typically targeted first. However, depending on the objective, younger essential workers are prioritized to control spread or seniors to directly control mortality. When the objective is minimizing deaths, relative to an untargeted approach, prioritization averts deaths on a range between 20,000 (when non-pharmaceutical interventions are strong) and 300,000 (when these interventions are weak). We illustrate how optimal prioritization is sensitive to several factors, most notably vaccine effectiveness and supply, rate of transmission, and the magnitude of initial infections.

scholarly journals Epidemiological characteristics and initial spatiotemporal visualisation of COVID-19 in a major city in the Middle East

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shahab MohammadEbrahimi ◽  
Alireza Mohammadi ◽  
Robert Bergquist ◽  
Fatemeh Dolatkhah ◽  
Mahsa Olia ◽  
...  
Keyword(s):  
Clinical Investigation ◽  
Case Fatality ◽  
Suburban Areas ◽  
Spatiotemporal Trends ◽  
Eastern Iran ◽  
Incidence And Mortality ◽  
North Eastern ◽  
Risk Areas ◽  
Fourth Wave ◽  
Epidemiological Characteristics

Abstract Background The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) emerged initially in China in December 2019 causing the COVID-19 disease, which quickly spread worldwide. Iran was one of the first countries outside China to be affected in a major way and is now under the spell of a fourth wave. This study aims to investigate the epidemiological characteristics of COVID-19 cases in north-eastern Iran through mapping the spatiotemporal trend of the disease. Methods The study comprises data of 4000 patients diagnosed by laboratory assays or clinical investigation from the beginning of the disease on Feb 14, 2020, until May 11, 2020. Epidemiological features and spatiotemporal trends of the disease in the study area were explored by classical statistical approaches and Geographic Information Systems. Results Most common symptoms were dyspnoea (69.4%), cough (59.4%), fever (54.4%) and weakness (19.5%). Approximately 82% of those who did not survive suffered from dyspnoea. The highest Case Fatality Rate (CFR) was related to those with cardiovascular disease (27.9%) and/or diabetes (18.1%). Old age (≥60 years) was associated with an almost five-fold increased CFR. Odds Ratio (OR) showed malignancy (3.8), nervous diseases (2.2), and respiratory diseases (2.2) to be significantly associated with increased CFR with developments, such as hospitalization at the ICU (2.9) and LOS (1.1) also having high correlations. Furthermore, spatial analyses revealed a geographical pattern in terms of both incidence and mortality rates, with COVID-19 first being observed in suburban areas from where the disease swiftly spread into downtown reaching a peak between 25 February to 06 March (4 incidences per km2). Mortality peaked 3 weeks later after which the infection gradually decreased. Out of patients investigated by the spatiotemporal approach (n = 727), 205 (28.2%) did not survive and 66.8% of them were men. Conclusions Older adults and people with severe co-morbidities were at higher risk for developing serious complications due to COVID-19. Applying spatiotemporal methods to identify the transmission trends and high-risk areas can rapidly be documented, thereby assisting policymakers in designing and implementing tailored interventions to control and prevent not only COVID-19 but also other rapidly spreading epidemics/pandemics.

scholarly journals Vaccine Effects on Susceptibility and Symptomatology Can Change the Optimal Allocation of COVID-19 Vaccines: South Korea as an Example

2021 ◽  
Vol 10 (13) ◽  
pp. 2813
Author(s):  
Wongyeong Choi ◽  
Eunha Shim
Keyword(s):  
South Korea ◽  
Optimal Allocation ◽  
Age Groups ◽  
Vaccination Strategy ◽  
Epidemiological Data ◽  
Health Interventions ◽  
Risk Of Disease ◽  
Age Structured ◽  
Effective Public Health ◽  
Country Specific

The approved coronavirus disease (COVID-19) vaccines reduce the risk of disease by 70–95%; however, their efficacy in preventing COVID-19 is unclear. Moreover, the limited vaccine supply raises questions on how they can be used effectively. To examine the optimal allocation of COVID-19 vaccines in South Korea, we constructed an age-structured mathematical model, calibrated using country-specific demographic and epidemiological data. The optimal control problem was formulated with the aim of finding time-dependent age-specific optimal vaccination strategies to minimize costs related to COVID-19 infections and vaccination, considering a limited vaccine supply and various vaccine effects on susceptibility and symptomatology. Our results suggest that “susceptibility-reducing” vaccines should be relatively evenly distributed among all age groups, resulting in more than 40% of eligible age groups being vaccinated. In contrast, “symptom-reducing” vaccines should be administered mainly to individuals aged 20–29 and ≥60 years. Thus, our study suggests that the vaccine profile should determine the optimal vaccination strategy. Our findings highlight the importance of understanding vaccine’s effects on susceptibility and symptomatology for effective public health interventions.

scholarly journals An analysis of the potential global impact of dosing regimen and rollout options for the ChAdOx1 nCoV-19 vaccine

2021 ◽  
Author(s):  
Ricardo Aguas ◽  
Anouska Bharath ◽  
Lisa White ◽  
Bo Gao ◽  
Merryn Voysey ◽  
...  
Keyword(s):  
High Risk ◽  
Low Income ◽  
Vaccine Efficacy ◽  
Socioeconomic Development ◽  
Optimal Allocation ◽  
Vaccination Strategy ◽  
Risk Groups ◽  
High Risk Group ◽  
Low Income Countries ◽  
Time Interval

Abstract Background The ongoing COVID-19 pandemic has placed an unprecedented health and economic burden on countries at all levels of socioeconomic development, emphasizing the need to evaluate the most effective vaccination strategy in multiple, diverse environments. The high reported efficacy, low cost, and long shelf-life of the ChAdOx1 nCoV-19 vaccine positions it well for evaluation in different settings. Methods Using data from the ongoing ChAdOx1 nCoV-19 clinical trials, an individual-based model was constructed to predict the 6-month population-level impact of vaccine deployment. A detailed probabilistic sensitivity analysis (PSA) was developed to evaluate the importance of epidemiological, demographic, immunological, and logistical factors in determining vaccine effectiveness. Using representative countries, logistical plans for vaccination rollout at various levels of vaccine availability and delivery speed, conditional on vaccine efficacy profiles (efficacy of the booster dose, time interval between doses, and relative efficacy of the first dose) were explored.Findings and Interpretation Our results highlight how expedient vaccine delivery to high-risk groups is critical in mitigating COVID-19 disease and mortality. In scenarios where the number of vaccine doses available is insufficient for high-risk groups (those aged more than 65 years) to receive two vaccine doses, administration of a single dose of vaccine is optimal. This effect is consistent even when vaccine efficacy after one dose is just 75% of the levels achieved after two doses. These findings offer a nuanced perspective of the critical drivers of COVID-19 vaccination effectiveness and can inform optimal allocation strategies. These are relevant to high-income countries with a large high-risk group population as well as to low-income countries with younger populations, where the cost and logistical challenges of procuring and delivering two doses for each citizen represent a significant challenge.

scholarly journals Conducting a national burden of disease study in South Korea: from past to present

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
S J Yoon ◽  
Y E Kim ◽  
H Park ◽  
I H Oh ◽  
M W Jo ◽  
...  
Keyword(s):  
South Korea ◽  
Low Income ◽  
Burden Of Disease ◽  
Disease Burden ◽  
High Income ◽  
Years Of Life Lost ◽  
High Income Group ◽  
Incidence And Mortality ◽  
Study Results ◽  
National Burden

Abstract South Korea has been measuring its own burden of disease since the early 2000s and has developed a methodology for its calculation. Since 2012, South Korea has been carrying out disease burden research through the Research and Development Project, supported by the Ministry of Health and Welfare. Because the Korean health insurance system covers the entire population of the country, the Korean National Burden of Disease (KNBD) study is based on individual claims data. Disease prevalence, incidence, and mortality rates, which are the epidemiologic indicators used to calculate burden of disease, are based on actual data, and the incidence-based approach is used for Years Lived with disability (YLD), Years of Life Lost (YLL), and Disability Adjusted Life Year (DALY). The KNBD study is conducted for 260 diseases and injuries and subdivided into sub-national levels. Disability weights (DW) are calculated to reflect the sociocultural characteristics of a disease. For cause-specific DWs, we conducted a self-administered web-based survey for medical doctors and students. Using a ranking method, we calculated cause-specific DWs. For this reason, KNBD study results cannot be directly compared with GBD results. The major findings of the KNBD study are as follows. In Korea, the DALY rate (per 100,000 people) steadily increased for all income levels. The higher the income, the lower the burden of disease; low-income people had a higher burden of disease than high-income people. However, thyroid cancer, refraction and accommodation disorders had a high burden of disease in the high-income group. Growth in the YLD rate was faster than in the YLL rate. In 2016 the leading causes of disease burden were diabetes mellitus, low back pain, and chronic obstructive pulmonary disease. We will present South Korea's disease burden calculation methodology and its results and share the efforts to calculate disease burden in other countries.

scholarly journals Measles Outbreak among Unvaccinated Children in Bajura

2010 ◽  
Vol 50 (180) ◽  
Author(s):  
S Sitaula ◽  
GR Awasthi ◽  
JB Thapa ◽  
A Ramaiya
Keyword(s):  
Vaccine Efficacy ◽  
Measles Virus ◽  
Case Fatality ◽  
Cold Chain ◽  
Endemic Region ◽  
Susceptible Population ◽  
Specimen Collection ◽  
Measles Outbreak ◽  
Epidemiological Characteristics

INTRODUCTION:Measles outbreak occurs when there are three or more laboratory confirmed measles cases in a village in a period of one month. Integrated surveillance system has helped to identify the measles outbreak, to characterize its epidemiology and to timely respond it.METHODS:This is a descriptive study of measles outbreak that occurred in Bajura district in February to March 2010. The epidemiological characteristics of the outbreak are described. The outbreak was investigated from 4-8 March 2010 with necessary epidemiological information and biological specimen collection. One month follow up was done to determine the clinical outcome of the measles cases.RESULTS:A total of 36 people had measles; 97% of them were under 15 years of age and 89% had not been immunized with measles vaccine. Attack rate and vaccine efficacy was 23% and 50% amongst children less than 15 years of age and case fatality rate (CFR) was 3%. Biological samples were collected from 11 patients; all of which tested IgM positive for measles and genotype D8 was isolated.CONCLUSIONS:CFR of this outbreak is higher than the national CFR. Vaccine efficacy of 50% points towards the need for investigation of vaccine logistics and cold chain system. Moreover, this laboratory test confirmed an outbreak showing that the measles virus could be imported from an endemic region and rapidly spread through a susceptible population who were previously not immunized.

scholarly journals Descriptive-epidemiological characteristics of lung cancer in Serbia

2008 ◽  
Vol 61 (1-2) ◽  
pp. 16-21 ◽  
Author(s):  
Natasa Maksimovic ◽  
Kyriakos Spanopoulos
Keyword(s):  
Lung Cancer ◽  
Direct Method ◽  
Age Groups ◽  
Malignant Tumour ◽  
Mortality Rates ◽  
Malignant Tumours ◽  
Mortality Trends ◽  
Incidence And Mortality ◽  
The Republic ◽  
Epidemiological Characteristics

Introduction. Lung cancer represents the most common malignant tumour among men, and appears more and more frequently among women in many countries worldwide. The aims of this descriptive epidemiological study were to evaluate the mortality trends of all malignant tumours and lung cancer in Central Serbia from 1990 to 1999, and to estimate the incidence, mortality and the basic demographic characteristics of lung cancer in Central Serbia in 1999. Material and methods. The source of data concerning cancer cases in 1999 was the Cancer Registry of Central Serbia, while data of the Republic Statistics Institute were used for the analysis of mortality trends for the period 1990-1999. All rates were standardized by the direct method, to the world standard population. Confidence intervals for mortality rates were assessed with 95% level of probability. Linear regression coefficient was determined by Fisher's test. Results. The mortality rates showed rising tendencies for both lung cancer (y=-1876.26+0.96x, p=0.028 for men; y=654.78U).33x, p-0.001 for women) and all malignant tumours (y=-4139.88+2.15x, p=0.163 for men; y=3649.68 + 1.88x, p=0.016 for women), with statistically significant increase being observed for all trends, except all malignant tumours among men. In the year 1999, lung cancer ranked first among men and third among women, with 29.2% and 10.3% of cancer mortality respectively. The age-specific mortality rates were much higher in men in all age groups. Mortality increased with age and the highest rates were found in the age group 70-74 for both sexes. The highest incidence and mortality rates were reported in Belgrade, Moravicki and Sumadijski district. .

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