scholarly journals Estimating reproduction numbers for adults and children from case data

2011 ◽  
Vol 8 (62) ◽  
pp. 1248-1259 ◽  
Author(s):  
K. Glass ◽  
G. N. Mercer ◽  
H. Nishiura ◽  
E. S. McBryde ◽  
N. G. Becker
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Reproduction Number ◽  
Age Groups ◽  
Reproduction Numbers ◽  
Influenza A H1n1 ◽  
Pandemic Influenza H1n1 ◽  
Adults And Children ◽  
Reporting Rates ◽  
The Impact

We present a method for estimating reproduction numbers for adults and children from daily onset data, using pandemic influenza A(H1N1) data as a case study. We investigate the impact of different underlying transmission assumptions on our estimates, and identify that asymmetric reproduction matrices are often appropriate. Under-reporting of cases can bias estimates of the reproduction numbers if reporting rates are not equal across the two age groups. However, we demonstrate that the estimate of the higher reproduction number is robust to disproportionate data-thinning. Applying the method to 2009 pandemic influenza H1N1 data from Japan, we demonstrate that the reproduction number for children was considerably higher than that of adults, and that our estimates are insensitive to our choice of reproduction matrix.

scholarly journals Seroprevalence study in Vojvodina (Serbia) following 2009 pandemic influenza A(H1N1)v

2012 ◽  
Vol 140 (11-12) ◽  
pp. 751-755
Author(s):  
Vladimir Petrovic ◽  
Zorica Seguljev ◽  
Jasminka Nedeljkovic ◽  
Mioljub Ristic
Keyword(s):  
Pandemic Influenza ◽  
Hemagglutination Inhibition ◽  
Influenza A ◽  
Herd Immunity ◽  
Age Groups ◽  
Immunization Coverage ◽  
Control Group ◽  
Study Objective ◽  
Seroprevalence Study ◽  
Influenza A H1n1

Introduction. The seroprevalence study was performed in Vojvodina during May and June 2010 in order to asses the effects of the 2009 pandemic influenza A(H1N1)v epidemic on herd immunity. It was a part of the Serbian Ministry of Health funded nationwide study. Objective. Prevalence of antibodies against 2009 pandemic influenza A(H1N1)v was determined in a 1% sample of the population monitored for influenza-like illness and acute respiratory infections in Vojvodina through sentinel surveillance system. Methods. The study sample involved a total of 1004 inhabitants of Vojvodina. The control group consisted of randomly selected and age-adjusted 1054 sera collected in the pre-pandemic period. Sera were tested by the reaction of hemagglutination inhibition using influenza A/California/7/2009 (H1N1) antigen in dilution from 1:8 to 1:256. Antibody titers ?1:32 and ?1:8 were considered protective and diagnostic, respectively. Results. The differences between control and study sera in all age groups were significant for both diagnostic ?1/8 and protective titres ?1/32 of hemagglutination inhibition antibodies (chi square test, p<0.001). The highest percentage of seropositive subjects was registered in the age group 15-19 years followed by children aged 5-14 years. Both diagnostic and protective titres were about twice higher in the vaccinated as compared to the non-vaccinated group. There were no statistically significant differences in seroprevalence between seven districts of Vojvodina. Conclusion. The 2009 pandemic influenza A(H1N1)v epidemic significantly influenced the herd immunity in our population regardless of low immunization coverage with highest immunity levels in adolescents aged 15-19 years and with similar herd immunity levels in all the regions in the province six months after the outbreak.

scholarly journals The return of the historic influenza A H1N1 virus and its impact on the population of the United Kingdom

1982 ◽  
Vol 89 (1) ◽  
pp. 89-100 ◽  
Author(s):  
P. Chakraverty ◽  
P. Cunningham ◽  
M. S. Pereira
Keyword(s):  
United Kingdom ◽  
Influenza A ◽  
Antigenic Variation ◽  
Adult Population ◽  
Age Distribution ◽  
Age Groups ◽  
The United Kingdom ◽  
Influenza A H1n1 ◽  
Older Adult Population ◽  
The Impact

SUMMARYThe epidemiology in the United Kingdom of the influenza A H1N1 subtype which returned in 1977 after an absence of 20 years is described for the four winter seasons from 1977/8 to 1980/1. The age distribution of virus isolates and the evidence for antigenic variation is presented. The impact in the susceptible age groups year by year is shown by the change in the population with specific antibody. There was the expected increase of antibody in those under the age of 21 but also evidence for a significant amount of infection or re-infection in the older adult population.

The Impact of Pandemic Influenza A H1N1 2009 on Australian Lung Transplant Recipients

2011 ◽  
Vol 11 (3) ◽  
pp. 568-574 ◽  
Author(s):  
B. J. H. Ng ◽  
A. R. Glanville ◽  
G. Snell ◽  
M. Musk ◽  
M. Holmes ◽  
...  
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Lung Transplant ◽  
Transplant Recipients ◽  
Influenza A H1n1 ◽  
Lung Transplant Recipients ◽  
The Impact

The impact of primer and probe-template mismatches on the sensitivity of pandemic influenza A/H1N1/2009 virus detection by real-time RT-PCR

2010 ◽  
Vol 48 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Chonticha Klungthong ◽  
Piyawan Chinnawirotpisan ◽  
Kittinun Hussem ◽  
Thipwipha Phonpakobsin ◽  
Wudtichai Manasatienkij ◽  
...  
Keyword(s):  
Real Time ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Virus Detection ◽  
Rt Pcr ◽  
Influenza A H1n1 ◽  
The Impact

Transmission and control in an institutional pandemic influenza A(H1N1) 2009 outbreak

2011 ◽  
Vol 140 (6) ◽  
pp. 1102-1110 ◽  
Author(s):  
N. ARINAMINPATHY ◽  
N. RAPHAELY ◽  
L. SALDANA ◽  
C. HODGEKISS ◽  
J. DANDRIDGE ◽  
...  
Keyword(s):  
High Risk ◽  
Infection Control ◽  
Pandemic Influenza ◽  
Summer School ◽  
Influenza A ◽  
Control Measures ◽  
Infection Control Measures ◽  
Influenza A H1n1 ◽  
Hygiene Measures ◽  
The Impact

SUMMARYA pandemic influenza A(H1N1) 2009 outbreak in a summer school affected 117/276 (42%) students. Residential social contact was associated with risk of infection, and there was no evidence for transmission associated with the classroom setting. Although the summer school had new admissions each week, which provided susceptible students the outbreak was controlled using routine infection control measures (isolation of cases, basic hygiene measures and avoidance of particularly high-risk social events) and prompt treatment of cases. This was in the absence of chemoprophylaxis or vaccination and without altering the basic educational activities of the school. Modelling of the outbreak allowed estimation of the impact of interventions on transmission. These models and follow-up surveillance supported the effectiveness of routine infection control measures to stop the spread of influenza even in this high-risk setting for transmission.

scholarly journals Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests

2011 ◽  
Vol 6 (3) ◽  
pp. e30-e34 ◽  
Author(s):  
Fengxiang Gao ◽  
Carol Loring ◽  
Michael Laviolette ◽  
Denise Bolton ◽  
Elizabeth R. Daly ◽  
...  
Keyword(s):  
Virus Infection ◽  
Pandemic Influenza ◽  
Diagnostic Tests ◽  
Influenza A ◽  
H1n1 Virus ◽  
Age Groups ◽  
Influenza A H1n1 ◽  
H1n1 Virus Infection

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.

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