Institute of Immunization and Prevention, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang, China.
Ningbo Health Information Center, Ningbo, Zhejiang, China.
BMC Geriatr. 2024 May 7;24(1):404. doi: 10.1186/s12877-024-05003-3.
Evidence on the effectiveness of influenza vaccination in the elderly is limited, and results are controversial. There are also few reports from China.
We conducted a test-negative case-control study design to estimate influenza vaccine effectiveness (VE) against laboratory-confirmed influenza-associated visits among elderly (aged ≥ 60 years) across four influenza seasons in Ningbo, China, from 2018 to 19 to 2021-22. Influenza-positive cases and negative controls were randomly matched in a 1:1 ratio according to age, sex, hospital, and date of influenza testing. We used logistic regression models to compare vaccination odds ratios (ORs) in cases to controls. We calculated the VE as [100% × (1-adjusted OR)] and calculated the 95% confidence interval (CI) around the estimate.
A total of 30,630 elderly patients tested for influenza with virus nucleic acid or antigen during the study period. After exclusions, we included 1 825 influenza-positive cases and 1 825 influenza-negative controls. Overall, the adjusted VE for influenza-related visits was 63.5% (95% CI, 56.3-69.5%), but varied by season. Influenza VE was 59.8% (95% CI, 51.5-66.7%) for influenza A and 89.6% (95% CI, 77.1-95.3%) for influenza B. The VE for ages 60-69 and 70-79 was 65.2% (95% CI, 55.4-72.9%) and 69.8% (95% CI, 58.7-77.9%), respectively, but only 45.4% (95% CI, 6.2-68.2%) for ages 80 and over.
Standard-dose inactivated influenza vaccine has shown good protection in the elderly in China. However, protection may not be satisfactory in people aged 80 years and older.
老年人流感疫苗有效性的证据有限，结果存在争议。中国也鲜有相关报告。
我们采用了病例对照研究设计，以评估在中国宁波进行的四个流感季节（2018 年至 19 年至 2021 年至 2022 年）中，流感疫苗对 60 岁及以上老年人实验室确诊的流感相关就诊的有效性。根据年龄、性别、医院和流感检测日期，对流感阳性病例和阴性对照进行 1:1 随机匹配。我们使用逻辑回归模型比较病例和对照的疫苗接种比值比（OR）。我们将疫苗效力（VE）计算为[100%×（1 调整 OR）]，并计算估计值周围的 95%置信区间（CI）。
在研究期间，共有 30630 名老年人接受了流感病毒核酸或抗原检测。排除后，我们纳入了 1825 例流感阳性病例和 1825 例流感阴性对照。总体而言，流感相关就诊的调整 VE 为 63.5%（95%CI，56.3-69.5%），但因季节而异。流感 A 的流感 VE 为 59.8%（95%CI，51.5-66.7%），流感 B 为 89.6%（95%CI，77.1-95.3%）。60-69 岁和 70-79 岁的 VE 分别为 65.2%（95%CI，55.4-72.9%）和 69.8%（95%CI，58.7-77.9%），但 80 岁及以上的 VE 仅为 45.4%（95%CI，6.2-68.2%）。
在中国，标准剂量的灭活流感疫苗对老年人表现出良好的保护作用。然而，对于 80 岁及以上的人群，保护效果可能并不理想。
