乙型肝炎病毒（HBV）是世界范围内常见的血液传播病原体，可导致病毒性肝炎、肝硬化、肝癌和其他肝脏疾病。特别是，隐匿性乙型肝炎病毒感染（OBI）可能是由导致病毒复制受到抑制的免疫反应引起的。肠道菌群可以改变人体的免疫状态，从而影响乙型肝炎病毒的复制。因此，为了确定 HBV 携带者和 OBI 携带者之间的肠道微生物群是否存在差异，我们收集了 18 名 HBV 携带者、24 名 OBI 献血者和 20 名健康献血者的粪便样本作为阴性对照。经过16S测序后，我们发现与健康献血者相比，OBI献血者样本中粪杆菌的丰度显着降低。与HBV携带者的样本相比，OBI献血者的样本中Subdolicapsulum丰度显着增加，这可能会刺激免疫激活，从而抑制HBV复制并有助于形成隐匿性感染。我们的研究结果揭示了肠道微生物群在 OBI 形成中的潜在作用，并进一步为治疗 HBV 感染提供了新的策略。 HBsAg) 阳性，乙型肝炎病毒 (HBV) DNA 阴性。肠道微生物群可能有助于免疫反应，从而抑制病毒复制，从而参与 OBI 的发展。 OBI献血者肠道菌群的研究提供了新的数据，极大地推进了我们对确定隐匿性乙型肝炎病毒感染的免疫机制的理解，有助于改进乙型肝炎病毒感染的治疗策略。

Hepatitis B virus (HBV), a common blood transmission pathogen worldwide, can lead to viral hepatitis, cirrhosis, liver cancer, and other liver diseases. In particular, occult hepatitis B virus infection (OBI) may be caused by an immune response leading to suppressed virus replication. Gut microbiota can change the immunity status of the human body and, therefore, affect the replication of HBV. Thus, to identify whether there are differences in gut microbiota between HBV carriers and OBI carriers, we collected fecal samples from 18 HBV carriers, 24 OBI blood donors, and also 20 healthy blood donors as negative control. After 16S sequencing, we found that the abundance of Faecalibacterium was significantly reduced in samples from OBI blood donors compared with those from healthy blood donors. Compared with samples from HBV carriers, the samples from OBI blood donors had a significantly increased abundance of Subdoligranulum, which might stimulate immune activation, thus inhibiting HBV replication and contributing to the formation of occult infection. Our findings revealed the potential role of gut microbiota in the formation of OBI and further provided a novel strategy for the treatment of HBV infection.IMPORTANCEOccult hepatitis B virus infection (OBI) is a special form of hepatitis B virus infection with hepatitis B surface antigen (HBsAg) positive and hepatitis B virus (HBV) DNA negative. Gut microbiota may contribute to the immune response leading to suppressed virus replication and, thus, participates in the development of OBI. The study on gut microbiota of OBI blood donors provides novel data considerably advancing our understanding of the immune mechanism for the determination of occult hepatitis B virus infection, which is helpful for improving the strategy of the treatment of HBV infection.