Department of Epidemiological Surveillance and Intervention, Hellenic Centre for Disease Control and Prevention, Athens, Greece; Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
National Influenza Reference Laboratory for Southern Greece, Hellenic Pasteur Institute, Athens, Greece.
Vaccine. 2015 Jan 3;33(2):367-73. doi: 10.1016/j.vaccine.2014.11.005. Epub 2014 Nov 18.
In 2013-2014 Greece experienced a resurgence of severe influenza cases, coincidental with a shift to H1N1pdm09 predominance. We sought to estimate Vaccine Effectiveness (VE) for this season using available surveillance data from hospitals (including both inpatients and outpatients).
Swab samples were sent by hospital physicians to one of three laboratories, covering the entire country, to be tested for influenza using RT-PCR. The test-negative design was employed, with patients testing positive serving as cases and those testing negative serving as controls. VE was estimated using logistic regression, adjusted for age group, sex, region and calendar time, with further adjustment for unknown vaccination status using inverse response propensity weights. Additional age group stratified estimates and subgroup estimates of VE against H1N1pdm09 and H3N2 were calculated.
Out of 1310 patients with known vaccination status, 124 (9.5%) were vaccinated, and 543 patients (41.5%) tested positive for influenza. Adjusted VE was 34.5% (95% CI: 4.1-55.3%) against any influenza, and 56.7% (95% CI: 22.8-75.7%) against H1N1pdm09. VE estimates appeared to be higher for people aged 60 and older, while in those under 60 there was limited evidence of effectiveness. Isolated circulating strains were genetically close to the vaccine strain, with limited evidence of antigenic drift.
These results suggest a moderate protective effect of the 2013-2014 influenza vaccine, mainly against H1N1pdm09 and in people aged 60 and over. Vaccine coverage was very low in Greece, even among groups targeted for vaccination, and substantial efforts should be made to improve it. VE can and should be routinely monitored, and the results taken into account when deciding on influenza vaccine composition for next season.
2013-2014 年期间，希腊流感病例再次爆发，恰逢 H1N1pdm09 成为主要流行病毒。我们试图利用从医院获取的现有监测数据（包括住院患者和门诊患者）来估算本季的疫苗效力（VE）。
医院医生将咽拭子样本送到三个实验室中的一个进行检测，采用 RT-PCR 检测流感。采用病例对照研究，咽拭子检测阳性的患者作为病例，阴性的患者作为对照。使用逻辑回归进行 VE 估计，根据年龄组、性别、地区和日历时间进行调整，使用反向反应倾向权重进一步调整未知疫苗接种状态。还计算了针对 H1N1pdm09 和 H3N2 的额外年龄组分层估计和 VE 亚组估计。
在已知疫苗接种状态的 1310 名患者中，124 名（9.5%）接种了疫苗，543 名（41.5%）患者流感检测呈阳性。调整后的 VE 对任何流感的效力为 34.5%（95%CI：4.1-55.3%），对 H1N1pdm09 的效力为 56.7%（95%CI：22.8-75.7%）。在 60 岁及以上的人群中，VE 估计值似乎更高，而在 60 岁以下的人群中，有效性证据有限。分离出的循环株与疫苗株在基因上非常接近，抗原漂移的证据有限。
这些结果表明，2013-2014 年流感疫苗具有一定的保护作用，主要针对 H1N1pdm09 和 60 岁及以上的人群。希腊的疫苗覆盖率非常低，即使在目标人群中也是如此，应该做出巨大努力来提高覆盖率。应常规监测 VE，并在决定下一季流感疫苗成分时考虑结果。
