Occupational Health Research Unit, Centro Médico Nacional "Siglo XXI", Instituto Mexicano del Seguro Social, Mexico City, Mexico.
Departments of Microbiology and Immunology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Mexico City, Mexico.
Arch Med Res. 2015 Feb;46(2):154-63. doi: 10.1016/j.arcmed.2015.03.001. Epub 2015 Mar 18.
In April 2009, a new strain of influenza A(H1N1) was identified in Mexico and in the U.S. In June 2009, WHO declared this a pandemic. Health care workers constituted a risk group for their close contact with infected individuals. The aim was to estimate seropositivity for A(H1N1)pdm09 in health staff at the Instituto Mexicano del Seguro Social.
A two-stage cross-sectional study, before and after vaccination in the same workers, was performed on a random sample of health-care workers. A socio-occupational questionnaire was applied and serum antibodies against influenza A(H1N1)pdm09 were determined through neutralization of retroviral pseudotypes; two logistic regression models for both were constructed.
The average (median/mean) age of 1378 participants from 13 work centers was 41.7 years and 68.7% (947) were women. Seroprevalence for the first stage was 26.5% (365) (7.4-43%) vs. 20.8% (11) in a control group from the blood bank; for the second stage, the vaccinated group was 33% (215) (18.2-47%) and 27% (196) (11.6-50%) for the unvaccinated group. In regression models, seropositivity was associated with occupational exposure to suspected influenza infected patients, being physicians, and being vaccinated.
Seropositivity against pandemic virus is similar to what was reported, both for vaccinated (2.8-40.9%) and unvaccinated (18.8-64.7%). Low seroprevalence in the vaccinated group indicates that between 67% and 73% were susceptible to infection. Given the relatively low vaccine-induced seropositivity, it is imperative to increase, hygiene and safety for health staff and at-risk populations, and strengthen epidemiological surveillance.
2009 年 4 月，在墨西哥和美国发现了一种新型甲型 H1N1 流感病毒株。2009 年 6 月，世界卫生组织宣布这是一种大流行。医护人员因与感染个体密切接触而构成风险群体。目的是评估墨西哥社会保障研究所卫生工作者中对甲型 H1N1pdm09 的血清阳性率。
在同一批工作人员中进行了两次疫苗接种前后的两阶段横断面研究，对卫生保健工作者的随机样本进行了研究。应用社会职业问卷，并通过逆转录病毒假型的中和作用来确定针对流感 A（H1N1）pdm09 的血清抗体；为两者构建了两个逻辑回归模型。
来自 13 个工作中心的 1378 名参与者的平均（中位数/均值）年龄为 41.7 岁，68.7%（947 人）为女性。第一阶段的血清阳性率为 26.5%（365）（7.4-43%），而血液库对照组为 20.8%（11）；第二阶段，接种组为 33%（215）（18.2-47%），未接种组为 27%（196）（11.6-50%）。在回归模型中，血清阳性与职业性接触疑似流感感染患者、医生和接种疫苗有关。
针对大流行病毒的血清阳性率与已报告的结果相似，无论是接种疫苗组（2.8-40.9%）还是未接种疫苗组（18.8-64.7%）。接种组的血清低阳性率表明，有 67%至 73%的人易感染。鉴于疫苗诱导的血清阳性率相对较低，必须加强卫生和安全措施，保护卫生工作者和高危人群，并加强流行病学监测。
