The coronavirus disease 2019 (COVID-19) pandemic substantially impacted different age groups, with children and young people not exempted. Many have experienced enduring health consequences. Presently, there is no consensus on the health outcomes to assess in children and young people with post-COVID-19 condition. Furthermore, it is unclear which measurement instruments are appropriate for use in research and clinical management of children and young people with post-COVID-19. To address these unmet needs, we conducted a consensus study, aiming to develop a core outcome set (COS) and an associated core outcome measurement set (COMS) for evaluating post-COVID-19 condition in children and young people. Our methodology comprised of two phases. In phase 1 (to create a COS), we performed an extensive literature review and categorisation of outcomes, and prioritised those outcomes in a two-round online modified Delphi process followed by a consensus meeting. In phase 2 (to create the COMS), we performed another modified Delphi consensus process to evaluate measurement instruments for previously defined core outcomes from phase 1, followed by an online consensus workshop to finalise recommendations regarding the most appropriate instruments for each core outcome. In phase 1, 214 participants from 37 countries participated, with 154 (72%) contributing to both Delphi rounds. The subsequent online consensus meeting resulted in a final COS which encompassed seven critical outcomes: fatigue; post-exertion symptoms; work/occupational and study changes; as well as functional changes, symptoms, and conditions relating to cardiovascular, neuro-cognitive, gastrointestinal and physical outcomes. In phase 2, 11 international experts were involved in a modified Delphi process, selecting measurement instruments for a subsequent online consensus workshop where 30 voting participants discussed and independently scored the selected instruments. As a result of this consensus process, four instruments met a priori consensus criteria for inclusion: PedsQL multidimensional fatigue scale for "fatigue"; PedsQL gastrointestinal symptom scales for "gastrointestinal"; PedsQL cognitive functioning scale for "neurocognitive" and EQ-5D for "physical functioning". Despite proposing outcome measurement instruments for the remaining three core outcomes ("cardiovascular", "post-exertional malaise", "work/occupational and study changes"), a consensus was not achieved. Our international, consensus-based initiative presents a robust framework for evaluating post-COVID-19 condition in children and young people in research and clinical practice via a rigorously defined COS and associated COMS. It will aid in the uniform measurement and reporting of relevant health outcomes worldwide.

2019 年冠状病毒病 (COVID-19) 大流行对不同年龄组产生了重大影响，儿童和青少年也不例外。许多人经历了持久的健康后果。目前，对于评估患有 COVID-19 后疾病的儿童和青少年的健康结果尚未达成共识。此外，尚不清楚哪些测量仪器适合用于 COVID-19 后儿童和青少年的研究和临床管理。为了解决这些未满足的需求，我们进行了一项共识研究，旨在开发核心结果集 (COS) 和相关的核心结果测量集 (COMS)，用于评估儿童和青少年的 COVID-19 后状况。我们的方法包括两个阶段。在第一阶段（创建 COS）中，我们进行了广泛的文献综述和结果分类，并在两轮在线修改德尔菲流程中对这些结果进行了优先排序，随后召开了共识会议。在第 2 阶段（创建 COMS），我们执行了另一个修改后的 Delphi 共识流程，以评估第 1 阶段之前定义的核心成果的测量工具，然后举行在线共识研讨会，以最终确定有关每个核心成果的最合适工具的建议。在第一阶段，来自 37 个国家的 214 名参与者参与其中，其中 154 名参与者 (72%) 参与了德尔福两轮融资。随后的在线共识会议产生了最终的 COS，其中包含七个关键成果：疲劳；劳累后症状；工作/职业和学习的变化；以及与心血管、神经认知、胃肠道和身体结果相关的功能变化、症状和状况。在第二阶段，11 位国际专家参与了修改后的德尔菲流程，为随后的在线共识研讨会选择测量工具，其中 30 名投票参与者对所选工具进行了讨论和独立评分。作为这一共识过程的结果，有四种仪器满足了先验共识纳入标准： PedsQL 多维疲劳量表“疲劳”；PedsQL 胃肠道症状量表“胃肠道”；PedsQL 认知功能量表代表“神经认知”，EQ-5D 代表“身体功能”。尽管提出了针对其余三个核心结果（“心血管”、“劳累后不适”、“工作/职业和学习变化”）的结果测量工具，但尚未达成共识。我们基于共识的国际倡议提供了一个强大的框架，通过严格定义的 COS 和相关的 COMS ，在研究和临床实践中评估儿童和青少年的 COVID-19 后状况。它将有助于在全球范围内统一测量和报告相关健康结果。