Incidence of H1N1 2009 Virus Infection through the Analysis of Paired Plasma Specimens among Blood Donors, France

摘要: Background Knowledge of the age-specific prevalence seroprotection and incidence seroconversion infection is necessary to complement clinical surveillance data statistical models. It provides basis for estimating future impact influenza A (H1N1pdm09) implementing appropriate prevention response strategies. Methods Using a cross-sectional design, two-stage stratified sampling paired plasma samples, we estimated protective level H1N1pdm09 antibodies in French adult population before after 2009/10 pandemic, proportion those susceptible that seroconverted due infection, from single sample 1,936 blood donors aged 20–70 years mainland France June 2010. Samples with haemagglutination inhibition (HI) titre ≥1:40 were considered seropositive, was defined as 4-fold increase absence vaccination or pre-pandemic seropositivity. Results Out donors, 1,708 included analysis. Seroprevalence pandemic 6.7% (95% CI 5.0, 8.9) no significant differences by age-group (p = 0.3). afterwards 23.0% 17.7, 29.3) 20–29 year olds having higher than older groups (p<0.001). Seroconversion 12.2% 6.9, 20.5). Younger age-group, against H1N1 being seropositive strongly associated post-pandemic seropositivity. Conclusions Before 2009/2010 winter season, only had usually protective. During first wave, seroprevalence wave rose 23%, either prepandemic seropositivity, vaccination. This relatively low latter figure contributed an extension target 2010/2011 season.