Influenza Division and
Influenza Division and.
Pediatrics. 2020 Nov;146(5). doi: 10.1542/peds.2020-1368. Epub 2020 Oct 5.
Influenza A(H1N1)pdm09 viruses initially predominated during the US 2018-2019 season, with antigenically drifted influenza A(H3N2) viruses peaking later. We estimated vaccine effectiveness (VE) against laboratory-confirmed influenza-associated hospitalizations and emergency department (ED) visits among children in the New Vaccine Surveillance Network.
We tested children 6 months to 17 years with acute respiratory illness for influenza using molecular assays at 7 pediatric hospitals (ED patients <5 years at 3 sites). Vaccination status sources were parental report, state immunization information systems and/or provider records for inpatients, and parental report alone for ED patients. We estimated VE using a test-negative design, comparing odds of vaccination among children testing positive versus negative for influenza using multivariable logistic regression.
Of 1792 inpatients, 226 (13%) were influenza-positive: 47% for influenza A(H3N2), 36% for A(H1N1)pdm09, 9% for A (not subtyped), and 7% for B viruses. Among 1944 ED children, 420 (22%) were influenza-positive: 48% for A(H3N2), 35% for A(H1N1)pdm09, 11% for A (not subtyped), and 5% for B viruses. VE was 41% (95% confidence interval [CI], 20% to 56%) against any influenza-related hospitalizations, 41% (95% CI, 11% to 61%) for A(H3N2), and 47% (95% CI, 16% to 67%) for A(H1N1)pdm09. VE was 51% (95% CI, 38% to 62%) against any influenza-related ED visits, 39% (95% CI, 15% to 56%) against A(H3N2), and 61% (95% CI, 44% to 73%) against A(H1N1)pdm09.
The 2018-2019 influenza vaccine reduced pediatric influenza A-associated hospitalizations and ED visits by 40% to 60%, despite circulation of a drifted A(H3N2) clade.
甲型流感 H1N1pdm09 病毒在美国 2018-2019 年流行期间占主导地位，随后抗原漂移的甲型流感 H3N2 病毒达到高峰。我们估计了新疫苗监测网络中儿童因实验室确诊的流感相关住院和急诊（ED）就诊的疫苗有效性（VE）。
我们使用分子检测方法在 7 家儿科医院（3 家医院 5 岁以下的 ED 患者）对急性呼吸道疾病的 6 个月至 17 岁儿童进行流感检测。疫苗接种状态的来源是父母报告、州免疫信息系统和/或住院患者的提供者记录，ED 患者仅接受父母报告。我们使用了测试阴性设计来估计 VE，通过多变量逻辑回归比较流感阳性儿童和流感阴性儿童接种疫苗的可能性。
在 1792 名住院患者中，有 226 名（13%）流感阳性：47%为甲型流感 H3N2，36%为甲型流感 H1N1pdm09，9%为 A（未分型），7%为 B 病毒。在 1944 名 ED 儿童中，有 420 名（22%）流感阳性：48%为甲型流感 H3N2，35%为甲型流感 H1N1pdm09，11%为 A（未分型），5%为 B 病毒。针对任何与流感相关的住院治疗，VE 为 41%（95%置信区间[CI]，20%至 56%），针对甲型流感 H3N2，VE 为 41%（95% CI，11%至 61%），针对甲型流感 H1N1pdm09，VE 为 47%（95% CI，16%至 67%）。针对任何与流感相关的 ED 就诊，VE 为 51%（95% CI，38%至 62%），针对甲型流感 H3N2，VE 为 39%（95% CI，15%至 56%），针对甲型流感 H1N1pdm09，VE 为 61%（95% CI，44%至 73%）。
尽管甲型流感 H3N2 出现了漂移，但 2018-2019 年的流感疫苗将儿童因甲型流感相关住院和 ED 就诊的风险降低了 40%至 60%。
