scholarly journals Pandemic influenza A(H1N1) 2009 breakthrough infections and estimates of vaccine effectiveness in Germany 2009-2010

2010 ◽  
Vol 15 (18) ◽  
Author(s):  
O Wichmann ◽  
P Stöcker ◽  
G Poggensee ◽  
D Altmann ◽  
D Walter ◽  
...  
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Rapid Assessment ◽  
Screening Method ◽  
Age Groups ◽  
Vaccine Effectiveness ◽  
Influenza A H1n1 ◽  
Reported Data ◽  
2009 Influenza Pandemic

During the 2009 influenza pandemic, a monovalent AS03-adjuvanted vaccine was almost exclusively used in Germany for immunisation against the 2009 pandemic influenza A(H1N1) virus. One-dose vaccination was recommended for all age groups. We applied the screening method for the rapid assessment of vaccine effectiveness (VE) based on reported data of vaccinated and unvaccinated pandemic influenza cases and vaccination coverage estimates. Preliminary results demonstrate excellent VE in persons aged 14-59 years (96.8%; 95% confidence interval (CI): 95.2-97.9) and moderately high VE in those 60 years or older (83.3%; 95% CI: 71.0-90.5).

scholarly journals Residual immunity in older people against the influenza A(H1N1) – recent experience in northern Spain

2009 ◽  
Vol 14 (39) ◽  
Author(s):  
E Pérez-Trallero ◽  
L Piñeiro ◽  
D Vicente ◽  
M Montes ◽  
G Cilla
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Virus ◽  
Influenza Pandemic ◽  
Age Groups ◽  
H3n2 Virus ◽  
Recent Experience ◽  
Northern Spain ◽  
Influenza A H1n1

The 2009 pandemic influenza A(H1N1) virus has a higher incidence in children and young adults, a pattern that has also been reported in seasonal influenza caused by the influenza A(H1N1) virus. We analysed age at infection in symptomatic patients with influenza in the Basque Country (northern Spain), reported through the sentinel influenza surveillance system which monitors 2.2-2.5% of the population. Between September 1999 and August 2009, influenza A(H3N2) or seasonal influenza A(H1N1) was detected in 941 patients, and from April to August 2009, pandemic influenza A(H1N1) was detected in 112 patients. The H3/H1 seasonal influenza ratio was between 3.3 and 3.4 in the under 60 year-olds, but 9.8 in older individuals, suggesting that people born before 1950 have residual immunity against the influenza A H1N1 subtype (both seasonal and pandemic). Introduction In 1957, the Asian influenza pandemic was caused by influenza A(H2N2) virus, which circulated until 1968 when it was displaced by the influenza A(H3N2) virus which was responsible for the Hong Kong pandemic. Before 1957, direct descendants of the influenza A(H1N1) virus that had caused the 1918 pandemic (Spanish flu) had circulated. In 1977, an influenza A(H1N1) strain re-emerged, which, together with the dominant influenza A(H3N2) strain, has been the cause of seasonal human influenza for more than three decades [1]. Despite the prolonged co-circulation of both subtypes, few studies have analysed their ability to affect distinct age groups. The current pandemic influenza A(H1N1) virus, influenza A(H1N1)v, which emerged in the spring of 2009, has spread throughout the world. The aim of this study was to compare the distribution in distinct age groups of infections caused by the two subtypes of seasonal influenza in the past 10 seasons and refer therelate this to recent infections due to influenza A(H1N1)v.

scholarly journals Ratio of Excess ED ILI Visits to Seroprevalence, Influenza A/H1N1 Infection, FL, 2009

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Richard Hopkins ◽  
Aaron Kite-Powell ◽  
Kate Goodin ◽  
Janet J. Hamilton
Keyword(s):  
Emergency Department ◽  
Emergency Department Visit ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Influenza Pandemic ◽  
H1n1 Infection ◽  
Influenza Like Illness ◽  
Influenza A H1n1 ◽  
2009 Influenza Pandemic

During the 2009 influenza pandemic, due to the 2009 pandemic influenza A (pH1N1) virus, there were an estimated 44 infections for every excess emergency department visit for influenza-like illness in Florida.

scholarly journals European Pandemic Influenza Preparedness Planning: A Review of National Plans, July 2016

2018 ◽  
Vol 13 (03) ◽  
pp. 582-592 ◽  
Author(s):  
Maaike Droogers ◽  
Massimo Ciotti ◽  
Peter Kreidl ◽  
Angeliki Melidou ◽  
Pasi Penttinen ◽  
...  
Keyword(s):  
Pandemic Influenza ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Small Population ◽  
Pandemic Preparedness ◽  
Preparedness Planning ◽  
Influenza A H1n1 ◽  
Robust Planning ◽  
2009 Influenza Pandemic ◽  
The Impact

AbstractPandemic influenza A (H1N1) commenced in April 2009. Robust planning and preparedness are needed to minimize the impact of a pandemic. This study aims to review if key elements of pandemic preparedness are included in national plans of European countries. Key elements were identified before and during the evaluations of the 2009 pandemic and are defined in this study by 42 items. These items are used to score a total of 28 publicly available national pandemic influenza plans. We found that plans published before the 2009 influenza pandemic score lower than plans published after the pandemic. Plans from countries with a small population size score significantly lower compared to national plans from countries with a big population (P <.05). We stress that the review of written plans does not reflect the actual preparedness level, as the level of preparedness entails much more than the existence of a plan. However, we do identify areas of improvement for the written plans, such as including aspects on the recovery and transition phase and several opportunities to improve coordination and communication, including a description of the handover of leadership from health to wider sector management and communication activities during the pre-pandemic phase. (Disaster Med Public Health Preparedness. 2019;13:582-592)

scholarly journals Children under 10 years of age were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic in Canada: ‎possible cohort effect following the 2009 influenza pandemic

2019 ◽  
Vol 24 (15) ◽  
Author(s):  
Danuta M Skowronski ◽  
Siobhan Leir ◽  
Gaston De Serres ◽  
Michelle Murti ◽  
James A Dickinson ◽  
...  
Keyword(s):  
General Population ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Age Distribution ◽  
Cohort Effect ◽  
Surveillance Network ◽  
Medical Visits ◽  
Influenza A H1n1 ◽  
2009 Influenza Pandemic ◽  
Negative Controls

Introduction Findings from the community-based Canadian Sentinel Practitioner Surveillance Network (SPSN) suggest children were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic. Aim To compare the age distribution of A(H1N1)pdm09 cases in 2018/19 to prior seasonal influenza epidemics in Canada. Methods The age distribution of unvaccinated influenza A(H1N1)pdm09 cases and test-negative controls were compared across A(H1N1)pdm09-dominant epidemics in 2018/19, 2015/16 and 2013/14 and with the general population of SPSN provinces. Similar comparisons were undertaken for influenza A(H3N2)-dominant epidemics. Results In 2018/19, more influenza A(H1N1)pdm09 cases were under 10 years old than controls (29% vs 16%; p < 0.001). In particular, children aged 5–9 years comprised 14% of cases, greater than their contribution to controls (4%) or the general population (5%) and at least twice their contribution in 2015/16 (7%; p < 0.001) or 2013/14 (5%; p < 0.001). Conversely, children aged 10–19 years (11% of the population) were under-represented among A(H1N1)pdm09 cases versus controls in 2018/19 (7% vs 12%; p < 0.001), 2015/16 (7% vs 13%; p < 0.001) and 2013/14 (9% vs 12%; p = 0.12). Conclusion Children under 10 years old contributed more to outpatient A(H1N1)pdm09 medical visits in 2018/19 than prior seasonal epidemics in Canada. In 2018/19, all children under 10 years old were born after the 2009 A(H1N1)pdm09 pandemic and therefore lacked pandemic-induced immunity. In addition, more than half those born after 2009 now attend school (i.e. 5–9-year-olds), a socio-behavioural context that may enhance transmission and did not apply during prior A(H1N1)pdm09 epidemics.

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 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 Clinical impact of influenza – lessons learnt from the pandemic influenza A (H1N1) 2009

2011 ◽  
Vol 32 (1) ◽  
pp. 29
Author(s):  
Alex Dierig ◽  
Gulam Khandaker ◽  
Robert Booy
Keyword(s):  
Clinical Features ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Gastrointestinal Symptoms ◽  
H1n1 Influenza ◽  
World Health ◽  
Pandemic H1n1 ◽  
Pandemic H1n1 Influenza ◽  
Influenza A H1n1

Influenza is generally an acute, self-limiting, febrile illness without further complications in the majority of people. However, it can be associated with severe morbidity and mortality and the burden of the disease on society is likely to be underestimated. In 2009 an outbreak of H1N1 influenza A virus infection was detected in Mexico with further cases soon observed worldwide. Subsequently, in June 2009, the first influenza pandemic of the 21st century due to influenza A (H1N1) was declared by the World Health Organization (WHO). There were many uncertainties regarding the virulence, clinical symptoms and epidemiological features of this newly evolved influenza A strain. Over time, many similarities, but also some differences between the pandemic H1N1 influenza A and seasonal influenza were identified. We recently performed a systematic review of the literature, looking at articles published between 1 April 2009 and 31 January 2010, to identify the epidemiological and clinical features of the pandemic H1N1 influenza. In this current article we compare our findings with others from the international literature. There was more severe impact on young and healthy adults, children, pregnant women and the obese. Clinical features in general were similar between seasonal and pandemic influenza; however, there were more gastrointestinal symptoms associated with pandemic H1N1 influenza. Shortness of breath was characteristic of more severe pH1N1 2009 infection with a higher possibility of being admitted to an intensive care unit (ICU).

scholarly journals Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18

2020 ◽  
Vol 25 (21) ◽  
Author(s):  
Lidia Redondo-Bravo ◽  
Concepción Delgado-Sanz ◽  
Jesús Oliva ◽  
Tomás Vega ◽  
Jose Lozano ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Pandemic ◽  
Age Groups ◽  
H3n2 Virus ◽  
Influenza B Virus ◽  
Influenza B ◽  
Intensity Level ◽  
Influenza A H1n1 ◽  
Epidemic Period ◽  
System Data

Background Understanding influenza seasonality is necessary for determining policies for influenza control. Aim We characterised transmissibility during seasonal influenza epidemics, including one influenza pandemic, in Spain during the 21th century by using the moving epidemic method (MEM) to calculate intensity levels and estimate differences across seasons and age groups. Methods We applied the MEM to Spanish Influenza Sentinel Surveillance System data from influenza seasons 2001/02 to 2017/18. A modified version of Goldstein’s proxy was used as an epidemiological-virological parameter. We calculated the average starting week and peak, the length of the epidemic period and the length from the starting week to the peak of the epidemic, by age group and according to seasonal virus circulation. Results Individuals under 15 years of age presented higher transmissibility, especially in the 2009 influenza A(H1N1) pandemic. Seasons with dominance/co-dominance of influenza A(H3N2) virus presented high intensities in older adults. The 2004/05 influenza season showed the highest influenza-intensity level for all age groups. In 12 seasons, the epidemic started between week 50 and week 3. Epidemics started earlier in individuals under 15 years of age (−1.8 weeks; 95% confidence interval (CI):−2.8 to −0.7) than in those over 64 years when influenza B virus circulated as dominant/co-dominant. The average time from start to peak was 4.3 weeks (95% CI: 3.6–5.0) and the average epidemic length was 8.7 weeks (95% CI: 7.9–9.6). Conclusions These findings provide evidence for intensity differences across seasons and age groups, and can be used guide public health actions to diminish influenza-related morbidity and mortality.

scholarly journals Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom

2012 ◽  
Vol 141 (3) ◽  
pp. 620-630 ◽  
Author(s):  
R. G. PEBODY ◽  
N. ANDREWS ◽  
D. M. FLEMING ◽  
J. McMENAMIN ◽  
S. COTTRELL ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Vaccine Effectiveness ◽  
Influenza B ◽  
The United Kingdom ◽  
Previous Season ◽  
Negative Case ◽  
Influenza A H1n1 ◽  
Control Study

SUMMARYAn analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI −6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group.

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