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 Convalescent Plasma Treatment Reduced Mortality in Patients With Severe Pandemic Influenza A (H1N1) 2009 Virus Infection

2011 ◽  
Vol 52 (4) ◽  
pp. 447-456 ◽  
Author(s):  
Ivan FN Hung ◽  
Kelvin KW To ◽  
Cheuk-Kwong Lee ◽  
Kar-Lung Lee ◽  
Kenny Chan ◽  
...  
Keyword(s):  
Intensive Care ◽  
Viral Load ◽  
Treatment Group ◽  
Respiratory Tract ◽  
Plasma Treatment ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Control Group ◽  
Severity Scores ◽  
Influenza A H1n1

Background. Experience from treating patients with Spanish influenza and influenza A(H5N1) suggested that convalescent plasma therapy might be beneficial. However, its efficacy in patients with severe pandemic influenza A(H1N1) 2009 virus (H1N1 2009) infection remained unknown. Methods. During the period from 1 September 2009 through 30 June 2010, we conducted a prospective cohort study by recruiting patients aged ≥18 years with severe H1N1 2009 infection requiring intensive care. Patients were offered treatment with convalescent plasma with a neutralizing antibody titer of ≥1:160, harvested by apheresis from patients recovering from H1N1 2009 infection. Clinical outcome was compared with that of patients who declined plasma treatment as the untreated controls. Results. Ninety-three patients with severe H1N1 2009 infection requiring intensive care were recruited. Twenty patients (21.5%) received plasma treatment. The treatment and control groups were matched by age, sex, and disease severity scores. Mortality in the treatment group was significantly lower than in the nontreatment group (20.0% vs 54.8%; P =  .01). Multivariate analysis showed that plasma treatment reduced mortality (odds ratio [OR], .20; 95% confidence interval [CI], .06-.69; P =  .011), whereas complication of acute renal failure was independently associated with death (OR, 3.79; 95% CI, 1.15-12.4; P =  .028). Subgroup analysis of 44 patients with serial respiratory tract viral load and cytokine level demonstrated that plasma treatment was associated with significantly lower day 3, 5, and 7 viral load, compared with the control group (P &lt;  .05). The corresponding temporal levels of interleukin 6, interleukin 10, and tumor necrosis factor α (P &lt;  .05) were also lower in the treatment group. Conclusions. Treatment of severe H1N1 2009 infection with convalescent plasma reduced respiratory tract viral load, serum cytokine response, and mortality.

scholarly journals Evaluation of Serological Diagnostic Methods for the 2009 Pandemic Influenza A (H1N1) Virus

2011 ◽  
Vol 18 (3) ◽  
pp. 520-522 ◽  
Author(s):  
Jesse Papenburg ◽  
Mariana Baz ◽  
Marie-Ève Hamelin ◽  
Chantal Rhéaume ◽  
Julie Carbonneau ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Pandemic Influenza ◽  
Hemagglutination Inhibition ◽  
Influenza A ◽  
H1n1 Virus ◽  
Diagnostic Methods ◽  
Rt Pcr ◽  
Virus Diagnosis ◽  
Household Contacts ◽  
Influenza A H1n1

ABSTRACTSerology improves influenza diagnosis by capturing cases missed by reverse transcriptase PCR (RT-PCR). We prospectively evaluated microneutralization and hemagglutination inhibition assays for 2009 influenza A (H1N1) virus diagnosis among 24 RT-PCR-confirmed cases and 98 household contacts. Compared to hemagglutination inhibition, microneutralization demonstrated a higher level of concordance with RT-PCR (kappa = 0.69 versus kappa = 0.60) and greater sensitivity (83% versus 71%;P= 0.016).

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 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 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 2009 pandemic influenza A(H1N1) virus in Scotland: geographically variable immunity in Spring 2010, following the winter outbreak

2010 ◽  
Vol 15 (24) ◽  
Author(s):  
W E Adamson ◽  
S Maddi ◽  
C Robertson ◽  
S McDonagh ◽  
P J Molyneaux ◽  
...  
Keyword(s):  
Older People ◽  
Pandemic Influenza ◽  
Influenza A ◽  
H1n1 Virus ◽  
Age Groups ◽  
Older Individuals ◽  
Serum Samples ◽  
Younger Adults ◽  
Influenza A H1n1

We determined the age- and location-specific seroprevalence of antibodies against 2009 pandemic influenza A(H1N1) virus in Scotland following the first two waves of infection. Serum samples collected following the winter outbreak were analysed by microneutralisation assay. The proportion of positive sera varied significantly between cities and, in the case of Inverness, between age groups (with younger adults more likely to be positive than older individuals). This study demonstrates that older people are no longer more likely to have antibodies against the virus than younger adults.

Sign in / Sign up

Export Citation Format

Share Document