MMWR Morb Mortal Wkly Rep. 2022 Mar 11;71(10):365-370. doi: 10.15585/mmwr.mm7110a1.
In the United States, annual vaccination against seasonal influenza is recommended for all persons aged ≥6 months except when contraindicated (1). Currently available influenza vaccines are designed to protect against four influenza viruses: A(H1N1)pdm09 (the 2009 pandemic virus), A(H3N2), B/Victoria lineage, and B/Yamagata lineage. Most influenza viruses detected this season have been A(H3N2) (2). With the exception of the 2020-21 season, when data were insufficient to generate an estimate, CDC has estimated the effectiveness of seasonal influenza vaccine at preventing laboratory-confirmed, mild/moderate (outpatient) medically attended acute respiratory infection (ARI) each season since 2004-05. This interim report uses data from 3,636 children and adults with ARI enrolled in the U.S. Influenza Vaccine Effectiveness Network during October 4, 2021-February 12, 2022. Overall, vaccine effectiveness (VE) against medically attended outpatient ARI associated with influenza A(H3N2) virus was 16% (95% CI = -16% to 39%), which is considered not statistically significant. This analysis indicates that influenza vaccination did not reduce the risk for outpatient medically attended illness with influenza A(H3N2) viruses that predominated so far this season. Enrollment was insufficient to generate reliable VE estimates by age group or by type of influenza vaccine product (1). CDC recommends influenza antiviral medications as an adjunct to vaccination; the potential public health benefit of antiviral medications is magnified in the context of reduced influenza VE. CDC routinely recommends that health care providers continue to administer influenza vaccine to persons aged ≥6 months as long as influenza viruses are circulating, even when VE against one virus is reduced, because vaccine can prevent serious outcomes (e.g., hospitalization, intensive care unit (ICU) admission, or death) that are associated with influenza A(H3N2) virus infection and might protect against other influenza viruses that could circulate later in the season.
在美国，除禁忌情况外，建议所有≥6 月龄的人每年接种季节性流感疫苗（1）。目前可用的流感疫苗旨在预防四种流感病毒：A（H1N1）pdm09（2009 年大流行病毒）、A（H3N2）、B/维多利亚系和 B/山形系。本季检测到的大多数流感病毒为 A（H3N2）（2）。除了 2020-21 季因数据不足以进行估计外，自 2004-05 季以来，CDC 每年都会根据美国流感疫苗有效性网络中因急性呼吸道感染（ARI）而就诊的实验室确诊、轻症/中度（门诊）ARI 患者的数据来估计季节性流感疫苗的有效性。本临时报告使用了 2021 年 10 月 4 日至 2022 年 2 月 12 日期间在美国流感疫苗有效性网络中登记的 3636 名患有 ARI 的儿童和成年人的数据。总体而言，疫苗对与 A（H3N2）病毒相关的门诊就医 ARI 的有效性为 16%（95%CI=-16%至 39%），这被认为没有统计学意义。这项分析表明，流感疫苗接种并没有降低本季迄今为止占主导地位的 A（H3N2）病毒引起的门诊就医疾病的风险。由于按年龄组或流感疫苗产品类型（1）进行登记的人数不足，因此无法生成可靠的疫苗有效性估计值。CDC 建议将流感抗病毒药物作为疫苗接种的辅助手段；在流感疫苗有效性降低的情况下，抗病毒药物的潜在公共卫生效益会放大。CDC 通常建议医疗保健提供者只要流感病毒仍在传播，就继续为≥6 月龄的人接种流感疫苗，即使一种病毒的疫苗有效性降低，因为疫苗可以预防与 A（H3N2）病毒感染相关的严重后果（例如住院、重症监护病房（ICU）入院或死亡），并可能预防该季晚些时候可能传播的其他流感病毒。
