乙型肝炎 - 是什么以及为什么重要
世界卫生组织（WHO）估计2billion individualshave been infected by Hepatitis B virus (HBV) at some point during their lifetime. Within the first 6 months after an individual is first infected with HBV, they experience a short term (acute) illness. In some cases of acute infection, the HBV remains in an individual’s body causing them to be chronically infected with Hepatitis B. The2015年报告肝炎estimated 257 million people (3.5% of the global population) were living with a chronic HBV infection.
Since HBV primarily attacks the liver, chronic HBV infection can imply significant long term health problems including liver damage, failure or even death. Untreated chronic infection can lead to life threatening long term complications such as chronic hepatitis, cirrhosis and hepatocellular carcinoma (a form of liver cancer). HBV is the 10th leading cause of death globally and results in每年500,000至700,000人死亡。Although relatively rare in the West, in regions where HBV remains endemic like Asia, the Western Pacific region and Africa, chronic HBV infection is common and individuals are often first exposed to the virus as infants or children.
乙肝可以通过体液传播ch as blood, semen etc. from an infected individual. The most common routes are sexual contact, sharing items (needles, razors, toothbrushes) with an infected person, exposure to infected blood or perinatal transmission (from a mother to child around the time of birth or during breastfeeding). The latter is the main route of transmission in areas where Hepatitis B is endemic like Asia, the Western Pacific and Africa.
The challenge and importance of preventing HBV transmission to infants
一个人年龄较小，当时他们会伴有急性HBV，他们发展慢性形式的可能性就越高。这是在下图中可视化的，这反映了与急性感染年龄相关的慢性HBV载体的个体的百分比。例如，大约90％的婴儿在出生时被感染的婴儿成为慢性携带者，相比之下，不到5％的人急性感染成人是该疾病的慢性携带者。
To minimize the risk of infants being acutely infected, babies born to HBV-positive women are regularly given vaccines and other immunoprophylaxis after birth. However 5-10% of vaccinated infants still contract the acute form of the virus. This indicates additional intervention is required to effectively reduce or eliminate transmission to infants.
婴儿是降低丙型肝炎患病率的特别关键目标人群，尤其是因为感染率仍然相对较高，并且早期暴露会导致这种疾病成为一种慢性终身疾病的风险更高。例如，长期对被感染为婴儿或幼儿的人的随访表明，由于肝硬化或肝细胞癌。
High HBV activity in the mother correlates with the infant’s risk of contracting the condition，即使婴儿出生后已免疫。因此，一种降低母亲HBV活性的抗病毒疗法可能能够防止婴儿患疾病。针对受慢性HBV影响的成年人有六种全球许可治疗，但目前没有定期在怀孕中使用。
一种抗病毒药物雌激素is an attractive candidate for preventing mother to child transmission of HBV. It has been classified as pregnancy category B, which implies that no risk has been shown in other studies, but risk has not been definitively excluded.
Previous studies (1，，，，2）报道说，在第二和第三个三物种中给药在封闭婴儿传播的母亲方面非常安全有效。但是，需要进一步的广泛研究以确保安全性和有效性在怀孕期间定期使用之前。
The issue of establishing drug safety in pregnancy
至关重要的是，任何针对HBV等产妇疾病的治疗都不会破坏婴儿的正常发育过程或引起严重的负面影响。
Thalidomide清楚地说明了这一点，Thalidomide被期望与母亲打击孕吐。什么时候thalidomide科学家于1957年首次被引入作为抗药药药物，不认为药物可以越过胎盘并伤害胎儿。不幸的是，事实并非phocomelia）as a result of thalidomide exposure.
Although finally taken off the market in 1961, the detrimental effects of thalidomide were long reaching and prompted the implementation of more rigorous rules for the testing and licensing of drugs.
此外，胎儿对药物的耐受性可能取决于其发育阶段 - 因此，某些药物可能是可以安全的怀孕后期，而在孕期胎儿非常容易受到环境侮辱的影响。
在怀孕期间的HBV治疗方面，如果在怀孕初期对孕妇进行抗病毒药，以及是否可以通过更脆弱，更发达的胎儿来容忍孕妇，那么效果是否存在差异。为了开始回答这个问题，Sun及其同事最近进行了学习如果在早期或中期开始，请评估链球菌的功效和安全性。
Antiviral HBV treatment during early and mid-pregnancy
Dr. Sun and colleagues compared markers of HBV infection and activity in three different experimental groups. One group of women began the antiviral treatment in early pregnancy (12 weeks), another in middle pregnancy (20-28 weeks) while the third group acted as a control and received no drug.
按照标准护理，所有组中的所有婴儿出生后接受了标准疫苗接种和预防治疗。出生后28周，对婴儿进行了测试，以检查是否存在HBV DNA或HBV抗体，这表明已经发生了疾病的儿童传播。
这项研究的结果是明确的 - 接受抗病毒药治疗的母亲所生的婴儿都没有均显示该疾病的生物标志物。相反，在怀孕期间未接受抗病毒药的组中，约有18％的婴儿出生后28周具有HBV活性标记。
与以前的研究相似，这些结果表明，在怀孕期间，患有抗病毒雌激素的母亲以及出生时的婴儿疫苗接种似乎比单独的婴儿疫苗接种更有效。此外，它表明，如果在早期妊娠与中期开始，抗病毒药施用可能同样有效。
展望未来
尽管Sun及其同事的工作表现出了令人鼓舞的结果，但它也提出了许多其他重要问题，这些问题还需要解决，在可以在对照临床试验之外使用抗病毒药之前。例如，最佳的时机和剂量仍有待确定，以及怀孕后期可以给予抗病毒药，并仍然成功防止传播。此外，尽管在怀孕期间母亲接受雌激素的婴儿中未观察到不良影响，但重要的是要注意，尚未排除潜在的负面影响，并且需要进行长期随访的更广泛的研究。
这项研究为计划的开发，实施和安全提供了关键的垫脚石，这些计划可以大大减少HBV-的围产期传播，并为婴儿提供健康的生活。
If you are interested in reading more on this topic, please visitBMC Gastroenterology或以下论文可以提供有关此博客中讨论的主题的更多深入信息：
About Hepatitis B during pregnancy
Maternal hepatitis B virus carrier status and pregnancy outcomes: a prospective cohort study
关于免疫
对中断丙型肝炎病毒母亲到儿童传播的免疫干预措施：随机对照试验的荟萃分析。
婴儿疫苗接种针对慢性丙型肝炎的功效和有效性在冈比亚肝炎干预研究（1986-90）和全国范围内的免疫免疫计划中
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