Kim Kyo-Hyun, Choi Yoon Gu, Yoon Hyun-Bae, Lee Jung-Woo, Kim Hyun-Wook, Chu Chaeshin, Park Young-Joon
The Third Republic of Korea Army, Ministry of National Defense, Seoul, Korea.
Osong Public Health Res Perspect. 2013 Aug;4(4):209-14. doi: 10.1016/j.phrp.2013.07.002. Epub 2013 Jul 23.
In December 2010, there was an outbreak of acute febrile respiratory disease in many Korean military camps that were not geographically related. A laboratory analysis confirmed a number of these cases to be infected by the pandemic influenza A(H1N1) 2009 (H1N1pdm09) virus. Because mass vaccination against H1N1pdm09 was implemented at the infected military camps eleven months ago, the outbreak areas in which both vaccinated and nonvaccinated individuals were well mixed, gave us an opportunity to evaluate the effectiveness of H1N1pdm09 vaccine through a retrospective cohort study design.
A self-administered questionnaire was distributed to the three military camps in which the outbreak occurred for case detection, determination of vaccination status, and characterization of other risk factors. The overall response rate was 86.8% (395/455). Case was defined as fever (≥38 °C) with cough or sore throat, influenza-like illness (ILI), and vaccination status verified by vaccination registry. Crude vaccine effectiveness (VE) was calculated as "1 - attack rate in vaccinated individuals/attack rate in nonvaccinated individuals", and adjusted VE was calculated as "1 - odds ratio" using logistic regression adjusted for potential confounding factor. A number of ILI definitions were used to test the robustness of the result.
The attack rate of ILI was 12.8% in register-verified vaccinated individuals and 24.0% in nonvaccinated individuals. The crude VE was thus calculated to be 46.8% [95% confidence interval (CI): 14.5-66.9]. The adjusted VE rate was 46.8% (95% CI: -9.4 to 74.1). Various combinations of ILI symptoms also showed similar VE rates.
We evaluated the effectiveness of H1N1pdm09 vaccine in the 2010-2011 season in an outbreak setting. Although the result was not sensitive to any analytical method used and ILI case definition, the magnitude of effectiveness was lower than estimated in the 2009-2010 season.
2010年12月，韩国多个地理位置不相关的军营爆发了急性发热性呼吸道疾病。实验室分析证实其中一些病例感染了2009年甲型H1N1大流行性流感（H1N1pdm09）病毒。由于在11个月前对受感染的军营实施了针对H1N1pdm09的大规模疫苗接种，且疫情爆发地区接种疫苗和未接种疫苗的人员充分混合，这使我们有机会通过回顾性队列研究设计来评估H1N1pdm09疫苗的有效性。
向发生疫情的三个军营发放了一份自填式问卷，用于病例检测、确定疫苗接种状况以及确定其他风险因素。总体回复率为86.8%（395/455）。病例定义为发热（≥38°C）伴咳嗽或咽痛、流感样疾病（ILI），并通过疫苗接种登记验证疫苗接种状况。粗疫苗效力（VE）计算为“1 - 接种疫苗个体的发病率/未接种疫苗个体的发病率”，调整后的VE通过对潜在混杂因素进行逻辑回归调整后的“1 - 优势比”来计算。使用了多种ILI定义来检验结果的稳健性。
经登记验证的接种疫苗个体中ILI的发病率为12.8%，未接种疫苗个体中为24.0%。因此，粗VE计算为46.8% [95%置信区间（CI）：14.5 - 66.9]。调整后的VE率为46.8%（95% CI：-9.4至74.1）。ILI症状的各种组合也显示出相似的VE率。
我们在疫情爆发背景下评估了2010 - 2011季节H1N1pdm09疫苗的有效性。尽管结果对所使用的任何分析方法和ILI病例定义均不敏感，但有效性的幅度低于2009 - 2010季节的估计值。
