scholarly journals The Time Required to Estimate the Case Fatality Ratio of Influenza Using Only the Tip of an Iceberg: Joint Estimation of the Virulence and the Transmission Potential

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Keisuke Ejima ◽  
Ryosuke Omori ◽  
Benjamin J. Cowling ◽  
Kazuyuki Aihara ◽  
Hiroshi Nishiura
Keyword(s):  
Influenza A ◽  
Case Fatality ◽  
Joint Estimation ◽  
Minimum Length ◽  
Public Health Response ◽  
Simple Method ◽  
Transmission Potential ◽  
Case Fatality Ratio ◽  
Influenza A H1n1 ◽  
Time Required

Estimating the case fatality ratio (CFR) of a novel strain of influenza virus during the early stage of the pandemic is one of key epidemiological tasks to be conducted as rapid research response. Past experience during the epidemics of severe acute respiratory syndrome (SARS) and influenza A (H1N1-2009) posed several technical challenges in estimating the CFR in real time. The present study aimed to develop a simple method to estimate the CFR based on readily available datasets, that is, confirmed cases and deaths, while addressing some of the known technical issues. To assess the reliability and validity of the proposed method, we examined the minimum length of time required for the assigned CFR to be included within the 95% confidence intervals and for the estimated CFR to be below a prespecified cut-off value by means of Monte Carlo simulations. Overall, the smaller the transmission potential was, the longer it took to compare the estimated CFR against the cut-off value. If policymaking and public health response have to be made based on the CFR estimate derived from the proposed method and readily available data, it should be noted that the successful estimation may take longer than a few months.

National Surveillance for Reye Syndrome: A Five-Year Review

PEDIATRICS ◽  
1982 ◽  
Vol 70 (6) ◽  
pp. 895-900 ◽  
Author(s):  
Eugene S. Hurwitz ◽  
David B. Nelson ◽  
Cornelia Davis ◽  
David Morens ◽  
Lawrence B. Schonberger
Keyword(s):  
Influenza A ◽  
Age Groups ◽  
Case Fatality ◽  
Large Percentage ◽  
Influenza B ◽  
Reye Syndrome ◽  
National Surveillance ◽  
Case Fatality Ratio ◽  
The Past ◽  
Influenza A H1n1

National surveillance for Reye syndrome conducted during five years, including the period 1973-1974 and December 1976 through November 1980, has resulted in the reporting of more than 2,000 cases of Reye syndrome. The highest reported incidence of Reye syndrome occurred during years of primary influenza B and A (H1N1) activity; the reported incidence during one period of influenza A (H3N2) activity was somewhat lower. Regional outbreaks of Reye syndrome have been associated with influenza A (H1N1) and B but not with influenza A (H3N2). Cases of Reye syndrome in whites tend to be distributed throughout all age groups whereas a large percentage of cases in blacks have been reported in infants <1 year of age in three of the past four years. Nationally, there has been a decline in the case-fatality ratio in recent years.

scholarly journals Estimation of the Time-dependent Reproduction Number of Influenza A(H1N1)pdm2009 in South Korea

2020 ◽  
Author(s):  
Yunjeong Lee ◽  
Dong Han Lee ◽  
Hee-Dae Kwon ◽  
Changsoo Kim ◽  
Jeehyun Lee
Keyword(s):  
South Korea ◽  
Influenza A ◽  
Reproduction Number ◽  
Time Estimation ◽  
Time Dependent ◽  
Estimation Of Parameters ◽  
Transmission Potential ◽  
Reproduction Numbers ◽  
Influenza A H1n1 ◽  
Feasible Range

Abstract Background: The reproduction number is one of the most crucial parameters in determining disease dynamics, providing a summary measure of the transmission potential. However, estimating this value is particularly challenging owing to the characteristics of epidemic data, including non-reproducibility and incompleteness.Methods: In this study, we propose mathematical models with different population structures; each of these models can produce data on the number of cases of the influenza A(H1N1)pdm09 epidemic in South Korea. These structured models incorporating the heterogeneity of age and region are used to estimate the time-dependent effective reproduction numbers. Subsequently, the age- and region-specific reproduction numbers are also computed to analyze the differences illustrated in the incidence data.Results: The basic SIR fails to provide a reasonable estimation of the reproduction numbers. The estimated values demonstrate a large variation and remains outside of the feasible range for the influenza, regardless of the time period for data. Real-time estimation using age- and region-structured models demonstrated that the effective reproduction number rose sharply during mid-October when the ㅜumber of patients increased dramatically. The reproduction number fell below unity at the end of October and stayed lower than unity indicating that the epidemic starts decreasing, which is consistent with the incidence data.Conclusions: Numerical results reveal that the introduction of heterogeneity into the population to represent the general characteristics of dynamics is essential for the robust estimation of parameters.

scholarly journals The Influenza Situation in the World and the Epidemic in Russia in Season 2016 - 2017

2017 ◽  
Vol 16 (4) ◽  
pp. 9-21 ◽  
Author(s):  
L. S. Karpova ◽  
Y. M. Pelikh ◽  
K. A. Stolyarov
Keyword(s):  
Influenza A ◽  
Age Groups ◽  
Case Fatality ◽  
Pandemic Virus ◽  
Database Research ◽  
Influenza A H1n1 ◽  
The World ◽  
Federal Districts ◽  
The City ◽  
Virus Influenza

Analysis of the situation for influenza in the world are drawn according to data published on the websites of the WHO, and the epidemic 2016 - 2017 in Russia - database «Research Influenza Institute» on the weekly morbidity, hospitalization, deaths from influenza in 61 observed the city. The influenza epidemic 2016 - 2017 started early, the duration of its in cities and in the country was longer and higher was the incidence of influenza and ARI in the cities and in the country than in the epidemic 2015 - 2016. But the epidemic of influenza A(H3N2) 2016 - 2017 there was less incidence morbidity at the peak, the frequency of hospitalization and, especially, mortality from influenza in the total population by 20 times, and in all age groups, especially among persons older than 65 years by 17.5 times, compared to the epidemic 2015 - 2016, caused by the pandemic virus influenza A(H1N1)pdm09. The peculiarities of the epidemic 2016 -17 according to the Federal districts, first of all, the absence of a second rise in the incidence of influenza in the South of Russia. The intensity of the epidemics of influenza A(H3N2) seasons 2016 - 17 and 2014 - 2015 - was average, and the epidemic A(H1N1) pdm09 2015 - 2016 - high. The case fatality rate in epidemics involving the influenza A(H3N2) remains significantly lower than in the epidemic caused by the pandemic virus influenza A(H1N1)pdm09.

Adult intensive-care patients with 2009 pandemic influenza A(H1N1) infection

2010 ◽  
Vol 139 (8) ◽  
pp. 1202-1209 ◽  
Author(s):  
C. FUHRMAN ◽  
I. BONMARIN ◽  
D. BITAR ◽  
T. CARDOSO ◽  
N. DUPORT ◽  
...  
Keyword(s):  
Risk Factors ◽  
Intensive Care ◽  
Antiviral Therapy ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Protective Factor ◽  
Severe Disease ◽  
Case Fatality ◽  
Icu Patients ◽  
Influenza A H1n1

SUMMARYIn France, the surveillance of hospitalized cases of pandemic influenza was implemented in July 2009 and restricted to intensive-care unit (ICU) patients in November. We described the characteristics of the 1065 adult patients admitted to ICUs and analysed risk factors for severe outcome (mechanical ventilation or death). Eighty-seven percent of cases were aged 15–64 years. The case-fatality ratio was 20%. The risk for severe outcome increased with age and obesity while this association was negative for chronic respiratory disease. Late antiviral therapy was associated with a severe outcome in ICU patients with risk factors (adjusted OR 2·0, 95% CI 1·4–3·0). This study confirms the considerable contribution of young adults to A(H1N1) 2009 mortality. It shows the role of obesity as an independent risk factor for severe disease, and of early antiviral therapy as a protective factor, at least in patients with risk factors.

scholarly journals 2009 Influenza A (H1N1) in Panama: a disease affecting children with a benign course

2011 ◽  
Vol 5 (09) ◽  
pp. 664-668 ◽  
Author(s):  
Javier Nieto- Guevara ◽  
Nestor Sosa ◽  
Mariana Garcia ◽  
Alex Martinez ◽  
Marlene Castillo
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Case Fatality Rate ◽  
Case Fatality ◽  
Nasopharyngeal Swab ◽  
Fatality Rate ◽  
Female Ratio ◽  
Severe Acute Respiratory Infection ◽  
Influenza A H1n1 ◽  
Epidemiological Characteristics

Introduction: Pandemic Influenza A (H1N1) was identified as the major febrile respiratory illness worldwide during the year 2009.  We present a report of its clinical and epidemiological characteristics in children and adults in Panama.  Methodology: A descriptive study from the database of the Gorgas Memorial Institute is presented.   We included patients with severe acute respiratory infection in whom a nasopharyngeal swab was positive by real-time RT-PCR for 2009 Influenza A (H1N1) pandemic virus and negative for seasonal influenza A H1 and H3. Results: From 26 April 2009 to 11 January 2010, confirmed cases of pandemic 2009 Influenza A (H1N1) reached 806. The overall incident rate was 23.35 cases of pandemic influenza per 100,000 habitants, with the highest incidence found in the age group between 10 to 14 years of age (58.67 cases per 100,000 habitants).  The median age for the cases was 13 years (ages ranging from one day to 88 years) and 71% were from the Panama City Metropolitan Area.  The male/female ratio was 1:1 and 90% were managed as out-patients.   An influenza-like syndrome was the presenting diagnosis in 99% of the cases.  Fever and cough were the most frequent symptoms reported in all age groups. The case fatality rate was 0.3 cases per 100,000 habitants. Conclusion: The 2009 Influenza A (H1N1) outbreak affected mainly the pediatric population, had a low case fatality rate, and was the predominant virus circulating in Panama during the 2009/2010 flu season

scholarly journals Estimation of the Reproduction Number of Influenza A(H1N1)pdm2009 in South Korea Using Heterogeneous Models

2020 ◽  
Author(s):  
Yunjeong Lee ◽  
Dong Han Lee ◽  
Hee-Dae Kwon ◽  
Changsoo Kim ◽  
jeehyun lee
Keyword(s):  
South Korea ◽  
Influenza A ◽  
Reproduction Number ◽  
Time Estimation ◽  
Estimation Of Parameters ◽  
Transmission Potential ◽  
Incidence Data ◽  
Reproduction Numbers ◽  
Number Of Patients ◽  
Influenza A H1n1

Abstract Background: The reproduction number is one of the most crucial parameters in determining disease dynamics, providing a summary measure of the transmission potential. However, estimating this value is particularly challenging owing to the characteristics of epidemic data, including non-reproducibility and incompleteness.Methods: In this study, we propose mathematical models with different population structures; each of these models can produce data on the number of cases of the influenza A(H1N1)pdm09 epidemic in South Korea. These structured models incorporating the heterogeneity of age and region are used to estimate the reproduction numbers at various terminal times. Subsequently, the age- and region-specific reproduction numbers are also computed to analyze the differences illustrated in the incidence data. Results: The basic SIR fails to provide a reasonable estimation of the reproduction numbers. The estimated values demonstrate a large variation and remains outside of the feasible range for the influenza, regardless of the time period for data. Real-time estimation using age- and region-structured models demonstrated that the effective reproduction number rose sharply during mid-October when the number of patients increased dramatically. The reproduction number fell below unity at the end of October and stayed lower than unity indicating that the epidemic starts decreasing, which is consistent with the incidence data. Conclusions: Numerical results reveal that the introduction of heterogeneity into the population to represent the general characteristics of dynamics is essential for the robust estimation of parameters.

scholarly journals Active surveillance of acute paediatric hospitalisations demonstrates the impact of vaccination programmes and informs vaccine policy in Canada and Australia

2020 ◽  
Vol 25 (25) ◽  
Author(s):  
Karina A Top ◽  
Kristine Macartney ◽  
Julie A Bettinger ◽  
Ben Tan ◽  
Christopher C Blyth ◽  
...  
Keyword(s):  
Public Health ◽  
Infectious Diseases ◽  
Active Surveillance ◽  
Influenza A ◽  
Monitoring Program ◽  
Emerging Infectious Diseases ◽  
Emerging Infections ◽  
Public Health Response ◽  
Influenza A H1n1 ◽  
The Impact

Sentinel surveillance of acute hospitalisations in response to infectious disease emergencies such as the 2009 influenza A(H1N1)pdm09 pandemic is well described, but recognition of its potential to supplement routine public health surveillance and provide scalability for emergency responses has been limited. We summarise the achievements of two national paediatric hospital surveillance networks relevant to vaccine programmes and emerging infectious diseases in Canada (Canadian Immunization Monitoring Program Active; IMPACT from 1991) and Australia (Paediatric Active Enhanced Disease Surveillance; PAEDS from 2007) and discuss opportunities and challenges in applying their model to other contexts. Both networks were established to enhance capacity to measure vaccine preventable disease burden, vaccine programme impact, and safety, with their scope occasionally being increased with emerging infectious diseases’ surveillance. Their active surveillance has increased data accuracy and utility for syndromic conditions (e.g. encephalitis), pathogen-specific diseases (e.g. pertussis, rotavirus, influenza), and adverse events following immunisation (e.g. febrile seizure), enabled correlation of biological specimens with clinical context and supported responses to emerging infections (e.g. pandemic influenza, parechovirus, COVID-19). The demonstrated long-term value of continuous, rather than incident-related, operation of these networks in strengthening routine surveillance, bridging research gaps, and providing scalable public health response, supports their applicability to other countries.

scholarly journals Influenza and Other Respiratory Viruses Involved in Severe Acute Respiratory Disease in Northern Italy during the Pandemic and Postpandemic Period (2009–2011)

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Elena Pariani ◽  
Marianna Martinelli ◽  
Marta Canuti ◽  
Seyed Mohammad Jazaeri Farsani ◽  
Bas B. Oude Munnink ◽  
...  
Keyword(s):  
Respiratory Disease ◽  
Influenza A ◽  
Case Fatality ◽  
Respiratory Viruses ◽  
Northern Italy ◽  
Influenza Viruses ◽  
Respiratory Pathogens ◽  
Severe Acute Respiratory Infection ◽  
Influenza A H1n1 ◽  
The Impact

Since 2009 pandemic, international health authorities recommended monitoring severe and complicated cases of respiratory disease, that is, severe acute respiratory infection (SARI) and acute respiratory distress syndrome (ARDS). We evaluated the proportion of SARI/ARDS cases and deaths due to influenza A(H1N1)pdm09 infection and the impact of other respiratory viruses during pandemic and postpandemic period (2009–2011) in northern Italy; additionally we searched for unknown viruses in those cases for which diagnosis remained negative. 206 respiratory samples were collected from SARI/ARDS cases and analyzed by real-time RT-PCR/PCR to investigate influenza viruses and other common respiratory pathogens; also, a virus discovery technique (VIDISCA-454) was applied on those samples tested negative to all pathogens. Influenza A(H1N1)pdm09 virus was detected in 58.3% of specimens, with a case fatality rate of 11.3%. The impact of other respiratory viruses was 19.4%, and the most commonly detected viruses were human rhinovirus/enterovirus and influenza A(H3N2). VIDISCA-454 enabled the identification of one previously undiagnosed measles infection. Nearly 22% of SARI/ARDS cases did not obtain a definite diagnosis. In clinical practice, great efforts should be dedicated to improving the diagnosis of severe respiratory disease; the introduction of innovative molecular technologies, as VIDISCA-454, will certainly help in reducing such “diagnostic gap.”

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