涉及安全性,FDA 叫停已上市的基孔肯雅热疫苗（Ixchiq）

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2025年8月22日美国食品药品监督管理局（FDA）宣布暂停 Valneva 公司基孔肯雅热疫苗 Ixchiq 的上市许可，理由是 “严重安全隐患”，声明中指出，Ixchiq疫苗 “似乎导致已接种的患者出现类似基孔肯雅热症状”。声明显示，截至目前，监管机构已记录到20多起接种者出现与类基孔肯雅热症状相符的严重副作用报告。在这些案例中，有21人需住院治疗，3人死亡，其中1例死于脑炎，且已证实与该疫苗有关联。

此次叫停距离 FDA 本月初解除该疫苗对 60 岁以上人群的使用限制仅过去两周，也让这款 2023 年 11 月全球首个获批的基孔肯雅热疫苗正式退出美国市场。根据Valneva公司上周五发布的消息，该暂停决定“立即生效，要求Valneva停止在美国销售和运输”Ixchiq疫苗。FDA的这一行动为Valneva公司及其Ixchiq疫苗长达数月的困境画上了阶段性句号。

今年5月，FDA和CDC曾建议暂停在60岁及以上人群使用该疫苗，原因是“出现了包括神经系统和心脏事件在内的严重不良事件报告”。当时，这两个机构已发现该年龄组有17例严重并发症，其中两例导致死亡。随后在本月早些时候，FDA解除了这一暂停令，但建议针对老年患者群体，为该疫苗贴上更严格的标签。FDA要求Valneva公司修改Ixchiq疫苗的处方信息，明确该疫苗仅适用于“高暴露风险”人群，以预防基孔肯雅热病毒感染。而该疫苗标签原先的表述为，Ixchiq适用于感染“风险增加”的人群。

此外，FDA还要求Valneva公司在疫苗相关说明中加入警示内容，以反映Ixchiq疫苗上市后监测到的这些情况，其中包括“与基孔肯雅热严重并发症相符的不良反应，这些不良反应已导致患者住院，其中1例死亡病例与脑炎相关”。

如今，该疫苗已被全面撤出市场。FDA在周五的最新公告中表示，“在大多数合理情况下，对该疫苗的获益-风险分析总体显示，其获益并不大于风险”，若继续为患者接种，“将对健康构成威胁”。

资料显示，Ixchiq是一种减毒活疫苗，于2023年11月成为首个获得FDA批准的基孔肯雅热疫苗。该批准是通过FDA的加速通道获得的，这要求Valneva在确认试验中验证该疫苗的临床益处。在上周五的公告中，FDA提到了Ixchiq批准的加速性质，指出“该疫苗的临床益处尚未在确认性临床研究中得到验证”。

▉ 从“首款获批”到“使用受限”

Ixchiq®是一种减毒活疫苗，于2023年11月获得FDA的加速批准，成为美国首个且唯一获批的基孔肯雅热疫苗，用于18岁及以上暴露风险增加的个体。2024年6月，该疫苗获得欧盟委员会的上市许可，用于12岁及以上人群。

基孔肯雅热 (Chikungunya) 是一种由埃及伊蚊或白纹伊蚊传播的病毒性疾病，可导致发热、严重关节痛等，对老年人和免疫力低下者威胁尤甚。Ixchiq®的获批曾被视为公共卫生领域的一大进展。然而，此次不良事件报告无疑为这款“明星疫苗”的前景蒙上了阴影。老年人群体往往伴有多种基础疾病，免疫系统反应也与年轻人不同，这使得疫苗在他们身上的安全性评估更为复杂和严峻。尽管FDA强调VAERS报告的不良事件与疫苗接种的因果关系尚待确认，但监管机构的审慎态度已清晰可见。

面对突如其来的监管调整，Valneva公司迅速做出反应，表示正与全球卫生当局紧密合作，全面审查相关安全性数据，并将在疫苗所有已上市地区启动对安全性报告的正式评估。公司强调将致力于确保疫苗的安全性与有效性。

▉ 8月22日美国FDA报道

FDA Update on the Safety of Ixchiq (Chikungunya Vaccine, Live). FDA Suspends Biologics License: FDA Safety Communication

AUDIENCE: Patient, Health Care Professional, Pharmacy, Cardiology, Neurology, Internal Medicine, Family Practice, Travel Clinics

UPDATE: On August 22, 2025, the US FDA’s Center for Biologics Evaluation and Research (CBER) has suspended the biologics license for Valneva Austria GmbH’s Ixchiq (Chikungunya Vaccine, Live). This vaccine was initially approved by FDA under the accelerated approval pathway in November of 2023 for the prevention of disease caused by the chikungunya virus (CHIKV) in individuals 18 years of age and older who are at increased risk of exposure to CHIKV. CBER’s decision is based on serious safety concerns related to the vaccine, which appears to be causing chikungunya-like illness in vaccine recipients. There has been one death from encephalitis directly attributable to the vaccine (CSF PCR was + for the vaccine strain of the virus) and over 20 reported serious adverse events that were consistent with chikungunya-like illness. Reported serious adverse events have included 21 hospitalizations and 3 deaths. Furthermore, the clinical benefit of the vaccine has not yet been verified in confirmatory clinical studies. CBER’s benefit-risk analysis broadly shows the vaccine does not have benefits outweighing risks, under most plausible scenarios. For these reasons, CBER believes this vaccine is not safe and that continued administration to the public would pose a danger to health.

On August 6, 2025, FDA lifted a pause in the use of Ixchiq in individuals 60 years of age and older and approved required updated labeling for Ixchiq, including revising the indication, and adding limitations of use and enhanced warnings and precautions to reflect serious postmarketing adverse reactions including hospitalizations and encephalitis in a person who died, with risk noted for individuals 65 years and older with chronic medical conditions.

On May 9, 2025, FDA issued a safety communication informing the public that the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) jointly recommended a pause in the use of Ixchiq (Chikungunya Vaccine, Live) in individuals 60 years of age and older while the Agencies undertook an investigation of postmarketing reports of serious adverse events, including neurologic and cardiac events, in individuals who have received the vaccine.

The November 9, 2023, approval of Ixchiq included a warning in the Prescribing Information informing that the vaccine may cause severe or prolonged chikungunya-like adverse reactions. Ixchiq contains a live, weakened version of the chikungunya virus and may cause symptoms in the vaccine recipient similar to those experienced by people who have chikungunya.

BACKGROUND: Ixchiq contains a live, weakened version of the chikungunya virus and may cause symptoms similar to those of chikungunya disease. Some of the postmarketing reports include adverse events that are consistent with severe complications of chikungunya disease, resulting in hospitalization; one person died from encephalitis.

Continuous monitoring and assessment of the safety of all vaccines remains an FDA priority. Suspected adverse events may be reported to the Vaccine Adverse Event Reporting System (VAERS), which is co-managed by FDA and CDC.