41 Pre and post-vaccination pandemic A(H1N1)pmd09 antibodies seroprevalence in Mexican health workers
研究了墨西哥谷地社保医护人员接种大流行流感疫苗前后的抗体阳性率，发现接种后仍有67%-73%的人易感，强调需加强防护和监测。
<h3>Objective</h3> To identify seropositivity for influenza A (H1N1) pdm09 in Social Security Mexican Institute (IMSS) health staff in the Valley of Mexico. <h3>Methodology</h3> Two stages cross sectional study was conducted on a random sample of pre-vaccination and post-vaccination against pandemic virus IMSS workers from Valley of Mexico and by job category. A social and labour questionnaire was applied and presence of antibodies against influenza A (H1N1) pdm09 in serum neutralisation test for pandemic virus retroviral pseudotypes, were determined. Two logistic regression models to identify risk factors in both stages were conducted. <h3>Results</h3> 1378 workers from 13 workplaces, with 41.7 years of age average and 68.7% (947) of them women, participated in both stages. The A (H1N1) pdm09 seroprevalence was at first stage: 26.5% (365) (7.4% - 43%) vs. 20.8% (11) in controls (blood donors); and at the second stage: 33% (215) (18.2% - 47%) in vaccinated and 27% in unvaccinated (196) (11.6% - 50%). In regression models, occupational exposure to patients with influenza suspicion, medical job category, and vaccination, determined the seropositivity of antibodies against the pandemic virus. <h3>Conclusions</h3> Seropositivity of antibodies against pandemic virus that we found in both groups, is in the range of the international studies: in vaccinated (2.8 to 40.9%) as in unvaccinated (18.8 to 64.7%). The response in the vaccinated (33%) and unvaccinated was intermediate (27%) so, between 67% and 73% of them continued to be susceptible to infection with influenza pandemic. Given the relatively low seropositivity induced by vaccine, is imperative to adopt and put into practice in permanent basis, hygienic and safety measures on health staff and populations under risk, and develop a permanent epidemiologic surveillance program over Mexican health system workers.