Pandemic Influenza A/H1N1pdm in Italy: Age, Risk and Population Susceptibility

摘要: Background A common pattern emerging from several studies evaluating the impact of 2009 A/H1N1 pandemic influenza (A/H1N1pdm) conducted in countries worldwide is low attack rate observed elderly compared to that children and young adults. The biological or social mechanisms responsible for age-specific risk infection are still be deeply investigated. Methods The level immunity against A/H1N1pdm pre post sera was determined using left over taken diagnostic purposes routine ascertainment obtained clinical laboratories. antibody titres were measured by haemagglutination inhibition (HI) assay. To investigate whether certain age groups had higher presence protective (≥1:40), calculated exact binomial 95% CI on both pre- post- serological data considered. estimate susceptibility we used an age-structured SEIR model. Results By comparing post-pandemic Italy found age- specific rates similar those other countries. Cumulative at end first season estimated 16.3% (95% 9.4%-23.1%). Modeling results allow ruling out hypothesis only characteristics contact network levels pre-pandemic infection. This means infection, suspected play important role pandemic, not H1N1pdm HI. Conclusions Our claim new better identify mechanisms, which might have with age. Moreover, our highlight need obtain early estimates differential any future pandemics more reliable real time critical epidemiological parameters.