Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Clin Infect Dis. 2021 Oct 20;73(8):1459-1468. doi: 10.1093/cid/ciab462.
Influenza vaccine effectiveness (VE) against a spectrum of severe disease, including critical illness and death, remains poorly characterized.
We conducted a test-negative study in an intensive care unit (ICU) network at 10 US hospitals to evaluate VE for preventing influenza-associated severe acute respiratory infection (SARI) during the 2019-2020 season, which was characterized by circulation of drifted A/H1N1 and B-lineage viruses. Cases were adults hospitalized in the ICU and a targeted number outside the ICU (to capture a spectrum of severity) with laboratory-confirmed, influenza-associated SARI. Test-negative controls were frequency-matched based on hospital, timing of admission, and care location (ICU vs non-ICU). Estimates were adjusted for age, comorbidities, and other confounders.
Among 638 patients, the median (interquartile) age was 57 (44-68) years; 286 (44.8%) patients were treated in the ICU and 42 (6.6%) died during hospitalization. Forty-five percent of cases and 61% of controls were vaccinated, which resulted in an overall VE of 32% (95% CI: 2-53%), including 28% (-9% to 52%) against influenza A and 52% (13-74%) against influenza B. VE was higher in adults 18-49 years old (62%; 95% CI: 27-81%) than those aged 50-64 years (20%; -48% to 57%) and ≥65 years old (-3%; 95% CI: -97% to 46%) (P = .0789 for interaction). VE was significantly higher against influenza-associated death (80%; 95% CI: 4-96%) than nonfatal influenza illness.
During a season with drifted viruses, vaccination reduced severe influenza-associated illness among adults by 32%. VE was high among young adults.
针对包括重症和死亡在内的多种严重疾病的流感疫苗效力（VE）仍未得到充分描述。
我们在美国 10 家医院的重症监护病房（ICU）网络中进行了一项病例对照研究，以评估 2019-2020 季节中流感相关严重急性呼吸道感染（SARI）的 VE，该季节的特征是漂移的 A/H1N1 和 B 谱系病毒的流行。病例为在 ICU 住院的成年患者和 ICU 外（为了捕捉严重程度的范围）的目标数量的患者，这些患者均具有实验室确诊的、与流感相关的 SARI。基于医院、入院时间和护理地点（ICU 与非 ICU），对病例对照进行频率匹配。调整了年龄、合并症和其他混杂因素的估计值。
在 638 例患者中，中位（四分位距）年龄为 57（44-68）岁；286 例（44.8%）患者在 ICU 治疗，42 例（6.6%）在住院期间死亡。45%的病例和 61%的对照接受了疫苗接种，总体 VE 为 32%（95%CI：2-53%），包括流感 A 为 28%（-9%至 52%）和流感 B 为 52%（13-74%）。18-49 岁成年人的 VE 更高（62%；95%CI：27-81%），而 50-64 岁成年人的 VE 较低（20%；-48%至 57%）和≥65 岁成年人的 VE 较低（-3%；95%CI：-97%至 46%）（P=0.0789 用于交互作用）。流感相关死亡的 VE 明显更高（80%；95%CI：4-96%），而非致命性流感疾病的 VE 较低。
在一个具有漂移病毒的季节，疫苗接种使成年人严重流感相关疾病的发生率降低了 32%。年轻人中的 VE 较高。
