Departamento de Epidemiologia, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, Portugal.
Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisboa, Portugal.
Influenza Other Respir Viruses. 2018 Jan;12(1):153-160. doi: 10.1111/irv.12501.
The aim of this study was to estimate excess pneumonia and influenza (P&I) hospitalizations during influenza epidemics and measure their correlation with influenza vaccine coverage in the 65 and more years old, according to the type/subtype of influenza virus.
The study period comprised week 40/1998-40/2015. Age-specific weekly P&I hospitalizations (ICD-9: 480-487) as main diagnosis were extracted from the National Hospital Discharge database. Age-specific baseline hospitalization rates were estimated by autoregressive integrated moving average (ARIMA) model without time periods with excess hospitalizations. Excess hospitalizations were calculated by subtracting expected hospitalization rates from the observed during influenza epidemic periods. Correlation between excess P&I hospitalizations and influenza vaccine coverage in the elderly was measured with Pearson correlation coefficient.
The average excess P&I hospitalizations/season was 19.4/10 (range 0-46.1/10 ), and higher excess was observed in young children with <2 years (79.8/10 ) and ≥65 years (68.3/10 ). In epidemics with A(H3) dominant, the highest excess hospitalizations were observed among 65 and over. Seasons which influenza B or A(H1)pdm09 dominance the highest excess was observed in children with <2 years. High negative correlation was estimated between excess hospitalizations associated with A(H3) circulation and vaccine coverage in the elderly (r = -.653; 95% CI: -0.950 to -0.137).
Over 80% of the influenza epidemics were associated with excess hospitalizations. However, excess P&I hospitalizations pattern differed from age group and circulating virus. This ecologic approach also identified a reduction in excess P&I associated with A(H3) circulation with increasing vaccine coverage in the elderly.
本研究旨在根据流感病毒的类型/亚型，估算老年人中流感相关肺炎和流感（P&I）住院人数的超额情况，并衡量其与流感疫苗接种覆盖率的相关性。
研究期间为 1998 年第 40 周至 2015 年第 40 周。从国家住院数据库中提取以 ICD-9 编码 480-487 为主要诊断的特定年龄组每周 P&I 住院人数。使用自回归综合移动平均（ARIMA）模型估算无超额住院人数的特定年龄组基础住院率。通过从流感流行期间的观察到的住院率中减去预期住院率来计算超额住院人数。使用 Pearson 相关系数衡量老年人超额 P&I 住院人数与流感疫苗覆盖率之间的相关性。
平均每季节超额 P&I 住院人数为 19.4/10（范围为 0-46.1/10），2 岁以下（79.8/10）和≥65 岁（68.3/10）的儿童中观察到的超额住院人数较高。在 A(H3) 占主导地位的流行季节中，65 岁及以上人群的住院人数最多。在 B 型或 A(H1)pdm09 占主导地位的季节中，2 岁以下儿童的超额住院人数最高。与 A(H3)循环相关的超额住院人数与老年人疫苗覆盖率之间估计存在高度负相关（r=-.653；95%CI：-0.950 至-0.137）。
超过 80%的流感流行与超额住院有关。然而，超额 P&I 住院人数的模式因年龄组和循环病毒而异。这种生态学方法还确定了与 A(H3) 循环相关的超额 P&I 住院人数随着老年人疫苗覆盖率的增加而减少。
