中国习 COVID-19 大流行前、期间和之后住院儿童肺炎支原体的流行病学特征

肺炎支原体 肺炎 （MP） 是全球范围内引起社区获得性肺炎 （CAP） 的常见病原体^[1]。 MP 感染占儿童肺炎相关住院人数的 10-40%^{[2， 3]。}.儿童和青少年中尤其危险，他们的发病率和死亡率都很高^[4]。. 在大多数情况下，MP 感染可独立消退。然而，它们可导致持续性肺炎和肺外损伤，导致严重的并发症，甚至导致h^[5]。. 因此，儿童发生 MP 感染，发病率和死亡率也很高^[6]。.MP 是自我复制的原核微生物，主要通过呼吸道飞沫和密切接触传播^[7]。与其他病原体相比，它是非典型的，原因有多种^[8]。它是最小的自我复制生物之一。它具有减少且稳定的基因组 （0.8 Mbp），缺乏细胞壁，生长缓慢（生成时间为 6 小时），并且需要密切接触才能传播^[9]。此外，它还会诱发非典型肺炎，这可能涉及宿主细胞介导的免疫^[10]。潜伏期为一到三周，个体从症状出现到康复后数周都能够保持传染^性[11]。.MP 感染可发生在任何季节，高峰每隔几年出现^{一次[12]。}这些感染 是 在中国北方的秋季和冬季更常见，而在中国南方的夏季和秋季更为普遍^[11]。自 冠状病毒病 （2019 年 12 月冠状病毒病 （COVID-19） 出现以来，已经实施了非药物干预措施 （NPI），例如佩戴口罩、保持手部卫生和保持社交距离，以控制 SARS-CoV-2 的传播^[6]。尽管这些措施有效地减少了 SARS-CoV-2 的传播，但它们也降低了y 艾德 MP 检出率，从根本上破坏 了先前建立的流行病学趋势^[5]。与其他呼吸道病原体类似，引入 NPI 后，儿童 MP 感染的发生率立即显着降低^[8]。. 然而，随着大流行限制措施的解除，MP 感染的发生率显着增加^[13]，引起了广泛关注，值得进一步调查。然而，关于中国 COVID-19 大流行各个阶段 MP 感染的长期流行病学特征的信息仍然s很少。本回顾性研究旨在分析 2017 年 1 月 1 日至 2023 年 12 月 31 日习安住院儿童在大流行前、 大流行和大流行后阶段

Mycoplasma pneumoniae (MP) is a common pathogen causing community-acquired pneumonia (CAP) worldwide^[1]. MP infections account for 10–40% of pediatric pneumonia-related hospitalizations^{[2, 3]}. Children and adolescents are particularly at high risk, with elevated morbidity and mortality rates^[4]. In most cases, MP infections can resolve spontaneously. However, they can lead to persistent pneumonia and extrapulmonary damage, causing severe complications and even death^[5]. Thus, pediatric MP infections also carry high morbidity and mortality rates^[6]. MP is a self-replicating prokaryotic microorganism primarily transmitted via respiratory droplets and close contact^[7]. It is atypical compared to other pathogens for multiple reasons^[8]: it is one of the smallest self-replicating organisms, possesses a reduced and stable genome (0.8 Mbp), lacks a cell wall, grows slowly with a generation time of 6 hours, and requires close contact for transmission^[9]. Additionally, it induces atypical pneumonia, which may involve host cell-mediated immunity^[10]. The incubation period ranges from 1 to 3 weeks, and individuals can remain contagious for weeks after the onset of symptoms and recovery^[11]. MP infections can occur in any season, with peaks emerging every few years^[12]. These infections are more common in autumn and winter in northern China, and prevalent in summer and autumn in southern China^[11]. Since the emergence of coronavirus disease 2019 (COVID-19) in December 2019, non-pharmaceutical interventions (NPIs) such as mask-wearing, hand hygiene, and social distancing have been implemented to control the spread of SARS-CoV-2^[6]. Although these measures effectively reduced SARS-CoV-2 transmission, they also lowered the detection rate of MP, fundamentally disrupting previously established epidemiological trends^[5]. Similar to other respiratory pathogens, the incidence of pediatric MP infections decreased significantly immediately following the introduction of NPIs^[8]. However, as pandemic restriction measures were lifted, the incidence of MP infections increased dramatically^[13], raising widespread concerns and warranting further investigation. Nevertheless, information regarding the long-term epidemiological characteristics of MP infections across different stages of the COVID-19 pandemic in China remains scarce. This retrospective study aims to analyze hospitalized children in Xi'an from January 1, 2017 to December 31, 2023 during pre-pandemic, pandemic, and post-pandemic periods.