第24届亚太地区肝脏研究协会年会（APASL 2014）于2014年3月12～15日在澳大利亚布里斯班召开。首都医科大学附属北京友谊医院肝病研究中心主任贾继东教授曾于2010年担任APASL主席。今天即APASL召开第二天，贾继东教授将就亚洲病毒性肝炎最紧迫的问题发言：乙肝病毒的母婴传播。
由于母婴传播是亚洲地区乙肝感染的主要途径，亚洲国家已花费人力和财力以阻止分娩过程中病毒的传播。目前已努力推广接种疫苗。台湾是首个实施普遍疫苗接种方案的地区，世界卫生组织推荐全球疾病负担较重的国家效仿这种策略。自实施以来的几十年中，上述策略已产生了巨大的经济和个人健康影响。然而，尽管这可能对亚太发达地区有效，但边远地区仍承受着不成比例的新病例负担。目前，世卫组织建议预防性联合治疗，其中包括出生时乙肝疫苗与乙肝免疫球蛋白（HBIG）注射联合治疗。
在中国，联合治疗的总有效率为90％，在某些地区甚至可达97％。目前的挑战是要进一步提高总有效率。贾教授说，“当然，100%预防母婴传播是理想目标”，“但实际上很难做到。”据贾教授称，存在两个主要障碍：孕妇筛查项目的可用性以及乙肝免疫球蛋白的供给。
在农村地区和贫穷的国家，用于孕妇乙肝病毒筛查的资源有限。虽然中国有一项普遍疫苗接种计划，但疫苗本身对携带病毒母亲的孩子并不是100 ％有效。因此，有必要确定这些女性，并对孩子进行额外的HBIG治疗。公众教育和宣传非常必要，可以让母亲了解这种预防方案。
在一些地区，HBIG的应用也是一个严重的问题。对贫困家庭来说，药物的成本往往过高，存储能力也限制了其在偏远地区的使用。如果HBIG治疗需求增加的话，公共资金将会补贴药物成本和治疗。
另一种策略是主动-被动预防。这涉及到婴儿疫苗接种治疗，以及为降低分娩前病毒载量而对孕妇进行的抗病毒治疗。在中国，正在进行的研究对怀孕最后三个月的乙肝病毒阳性孕妇抗病毒治疗进行了重点分析。结果表明，与标准预防法相比，抗病毒治疗具有非常好的疗效和安全性。
这种策略的一个主要问题是对胎儿的潜在危害。已知一些抗病毒药物有致畸作用，所以医生只能使用那些已在孕妇中研究了的药物。贾教授建议使用替比夫定和替诺福韦作为主动-被动预防的一部分。拉米夫定用于短期使用也能接受。
原文阅读》》》Updates on Prevention of Mother-To-Child Transmission
Prof. Ji-Dong Jia, Director of the Liver Research Centre at the Beijing Friendship Hospital, Capital Medical University in Beijing, China. Past President of APASL 2010. On Thursday, he is scheduled to speak on Asia’s most pressing issue in viral hepatitis: the transmission of HBV from mother-to-child.
As the main route of infection in the region, countries have been spending human and financial resources to halt the spread of the virus during childbirth. Efforts at vaccination are already widespread in the region. Taiwan was the first area to implement universal vaccine programs and the WHO followed suit by recommending the strategy to countries around the world with large disease burdens. This has had an enormous economic and personal health impact in the decades since implementation. However, while this may be effective in developed regions of the Asia-Pacific, remote locations still bear a disproportionate burden of new cases. Currently, the WHO recommends a combination of prophylactic therapy, which includes a birth dose of the hepatitis B vaccine in conjunction with an injection of hepatitis B immune globulin (HBIG).
In China, this combination has an overall efficacy rate of 90%, and can even climb to 97% in certain areas. The challenge is now to bring these rates up further. “One hundred percent prevention of mother-to-infant transmission is, of course, the ideal goal,” says Prof. Jia, “but it is actually very difficult to attain.” According to Prof. Jia, two major hurdles exist: availability of screening programs for pregnant women and supplies of HBIG.
In rural areas and poorer countries,there are limited resources for screening mothers for HBV. While China has a universal vaccination program, the vaccine itself is not 100% effective for children of mothers who carry the virus. Therefore, it is necessary to identify these women and prepare the additional HBIG to give to the child. Public education and outreach are necessary to make mothers aware of the potential preventative options.
Availability of HBIG can also be a serious problem in some regions. The cost of the drug is often too high for poor families to afford, and storage capabilities limit its use in remote areas. Public funds will have to subsidise both the cost of the drug and its administration if access to HBIG therapy is to be increased.
Another strategy is active-passive prophylaxis. This involves vaccination therapy for the child, as well as antiviral therapy for the mother to reduce her viral load prior to birth. In China, there are ongoing studies that focus on offering HBV-positive mothers antiviral therapy in the last trimester of pregnancy. The results, according to Prof. Jia “show very good efficacy and safety profile for antiviral therapy compared to standard prophylaxis methods.”
One major concern of this strategy is the potential harm to the foetus. Some antivirals are known to have teratogenic effects, so physicians must stick only to those drugs that have been studied in pregnant women. Prof. Jia recommends telbivudine and tenofovir as part of the active-passive prophylaxis. Lamivudine is also acceptable for short-term use.
