[Technical guidelines for seasonal influenza vaccination in China (2022-2023)].

Influenza is an acute respiratory infectious disease caused by the influenza virus, which seriously affects human health. The influenza virus has frequent antigenic drifts that can facilitate escape from pre-existing population immunity and lead to the rapid spread and annual seasonal epidemics. Influenza outbreaks occur in crowded settings, such as schools, kindergartens, and nursing homes. Seasonal influenza epidemics can cause 3-5 million severe cases and 290 000-650 000 respiratory disease-related deaths worldwide every year. Pregnant women, infants, adults 60 years and older, and individuals with comorbidities or underlying medical conditions are at the highest risk of severe illness and death from influenza. Given the ongoing COVID-19 pandemic, some provinces in southern China had a summer peak of influenza. SARS-CoV-2 may co-circulate with influenza and other respiratory viruses in the upcoming winter-spring influenza season. Annual influenza vaccination is an effective way to prevent influenza, reduce influenza-related severe illness and death, and reduce the harm caused by influenza-related diseases and the use of medical resources. The currently approved influenza vaccines in China include trivalent inactivated influenza vaccine (IIV3), quadrivalent inactivated influenza vaccine (IIV4), and trivalent live attenuated influenza vaccine (LAIV3). IIV3 is produced as a split virus vaccine and subunit vaccine; IIV4 is produced as a split virus vaccine; and LAIV3 is a live, attenuated virus vaccine. Except for some jurisdictions in China, the influenza vaccine is a non-immunization program vaccine-voluntarily and self-paid. China CDC has issued 'Technical Guidelines for Seasonal Influenza Vaccination in China' every year from 2018 to 2021. Over the past year, new research evidence has been published at home and abroad. To better guide the prevention and control of influenza and vaccination in China, the National Immunization Advisory Committee (NIAC) Influenza Vaccination Technical Working Group updated and revised the 2021-2022 Technical Guidelines with the latest research progress into the 'Technical Guidelines for Seasonal Influenza Vaccination in China (2022-2023)'. The new version has updated five key areas: (1) new research evidence-especially research conducted in China-has been added, including new estimates of the burden of influenza disease, assessments of influenza vaccine effectiveness and safety, and analyses of the cost-effectiveness of influenza vaccination; (2) policies and measures for influenza prevention and control that were issued by the government over the past year; (3) influenza vaccines approved for marketing in China this year; (4) composition of trivalent and quadrivalent influenza vaccines for the 2022-2023 northern hemisphere influenza season; and (5) recommendations for influenza vaccination during the 2022-2023 influenza season. The 2022-2023 Guidelines recommend that vaccination clinics provide influenza vaccination services to all people aged 6 months and above who are willing to be vaccinated and have no contraindications to the influenza vaccine. For adults ≥ 18 years, co-administration of COVID-19 and inactivated influenza vaccines in separate arms is acceptable regarding immunogenicity and reactogenicity. For people under 18 years old, there should be at least 14 days between influenza vaccination and COVID-19 vaccination. The Guidelines express no preference for influenza vaccine type or manufacturer-any approved, age-appropriate influenza vaccines can be used. To minimize harm from influenza and limit the impact on the effort to prevent and control COVID-19 in China, the Technical Guidelines recommend priority vaccination of the following high-risk groups during the upcoming 2022-2023 influenza season: (1) healthcare workers, including clinical doctors and nurses, public health professionals, and quarantine professionals; (2) volunteers and staff who provide services and support for large events; (3) people living in nursing homes or welfare homes and staff who take care of vulnerable, at-risk individuals; (4) people who work in high population density settings, including teachers and students in kindergartens and primary and secondary schools, and prisoners and prison staff; and (5) people at high risk of influenza, including adults ≥ 60 years of age, children 6-59 months of age, individuals with comorbidities or underlying medical conditions, family members and caregivers of infants under 6 months of age, and pregnant women. Children 6 months to 8 years of age who receive inactivated influenza vaccine for the first time should receive two doses, with an inter-dose interval of 4 or more weeks. Children who previously received the influenza vaccine and anyone 9 years or older need only one dose. LAIV is recommended only for a single dose regardless of the previous influenza vaccination. Vaccination should begin as soon as influenza vaccines become available and preferably should be completed before the onset of the local influenza season. Repeated influenza vaccination during a single influenza season is not recommended. Vaccination clinics should provide immunization services throughout the epidemic season. Pregnant women can receive inactivated influenza vaccine at any stage of pregnancy. These guidelines are intended for use by staff of CDCs, healthcare workers, maternity and child care institutions and immunization clinic staff members who work on influenza control and prevention. The guidelines will be updated periodically as new evidence becomes available.流感是由流感病毒引起的一种急性呼吸道传染病，严重危害人群健康。流感病毒其抗原性易变，传播迅速，每年可引起季节性流行，在学校、托幼机构和养老院等人群聚集的场所易发生暴发疫情。每年季节性流感流行在全球可导致300万~500万重症病例，29万~65万呼吸道疾病相关死亡。孕妇、婴幼儿、老年人和慢性基础疾病患者等高危人群，患流感后出现严重疾病和死亡的风险较高。尤其是全球新型冠状病毒肺炎（新冠肺炎）疫情严重流行态势仍在持续，今年我国南方部分省份出现夏季流感流行高峰，今冬明春可能会出现新冠与流感等呼吸道传染病叠加流行的情况。接种流感疫苗是预防流感、减少流感相关重症和死亡的有效手段，可以减少流感相关疾病带来的健康危害及对医疗资源的挤兑。我国现已批准上市的流感疫苗有三价灭活流感疫苗（IIV3）、四价灭活流感疫苗（IIV4）和三价减毒活流感疫苗（LAIV3），IIV3包括裂解疫苗和亚单位疫苗，IIV4为裂解疫苗，LAIV3为减毒疫苗。流感疫苗在我国属于非免疫规划类疫苗，居民自愿接种。2018年以来，中国疾病预防控制中心每年印发当年度的《中国流感疫苗预防接种技术指南》。一年来，新的研究证据在国内外发表，为更好地指导我国流感预防控制和疫苗接种工作，国家免疫规划技术工作组流感疫苗工作组综合国内外最新研究进展，在2021年版指南的基础上进行了更新和修订，形成了《中国流感疫苗预防接种技术指南（2022—2023）》。本指南更新的内容主要包括以下几个方面：第一，增加了新的研究证据，尤其是我国的研究结果，包括流感疾病负担、疫苗效果、疫苗安全性监测、疫苗预防接种成本效果等；第二，更新了一年来国家出台的有关流感防控政策和措施；第三，更新了2022—2023年度国内批准上市及批签发的流感疫苗种类；第四，更新了本年度三价和四价流感疫苗组分；第五，更新了2022—2023年度的流感疫苗接种建议。本指南建议：原则上，接种单位应为≥6月龄所有愿意接种流感疫苗且无接种禁忌的人提供接种服务。≥18岁人群可在一次接受免疫服务时，在两侧肢体分别接种灭活流感疫苗和新冠疫苗；<18岁人群，建议流感疫苗与新冠疫苗接种间隔仍大于14 d。对可接种不同类型或不同厂家疫苗产品的人群，可由受种者自愿选择接种任何一种流感疫苗，无优先推荐。结合今年新冠肺炎疫情形势，为尽可能降低流感的危害和对新冠疫情防控的影响，优先推荐以下重点和高风险人群及时接种：（1）医务人员，包括临床救治人员、公共卫生人员、卫生检疫人员等；（2）大型活动参加人员和保障人员；（3）养老机构、长期护理机构、福利院等人群聚集场所脆弱人群及员工；（4）重点场所人群，如托幼机构、中小学校的教师和学生，监所机构的在押人员及工作人员等；（5）其他流感高风险人群，包括≥60岁居家老年人、6月龄~5岁儿童、慢性病患者、<6月龄婴儿的家庭成员和看护人员以及孕妇。对于IIV，6月龄~8岁儿童首次接种流感疫苗的应接种2剂次，间隔≥4周；2021—2022年度或以前接种过1剂次或以上流感疫苗的儿童，建议接种1剂次；≥9岁儿童和成人仅需接种1剂次。对于LAIV，无论是否接种过流感疫苗，仅接种1剂次。建议各地在疫苗供应到位后尽早开展接种工作，尽量在当地流感流行季前完成接种。同一流行季，已按照接种程序完成全程接种的人员，无需再次接种。孕妇在孕期的任一阶段均可接种灭活流感疫苗。接种单位在整个流行季节都可以提供接种服务。本指南适用于疾控机构、医疗机构、妇幼保健机构和接种单位等从事流感防治相关的专业人员。根据国内外研究进展，本指南今后亦将定期更新、完善。.