乙肝疫苗效果持续终生

清照

  
　　医学专家们认为，没有必要追加接种乙肝疫苗。

　　以伦敦Guy 's King and St.Thomas医院Banatvala教授为首的有关乙肝免疫问题欧洲专家组认为，如基础免疫获得成功，免疫系统又没有问题者，即使体内未达充足量的抗体，感染时亦可通过记忆细胞产生迅速而有效的免疫应答。(Lancet 355∶561)

　　为了获得完全的基础免疫效果，乙肝疫苗接种共三次，第一次与第二次间隔4～6周；第二次接种时已开始形成乙肝表面抗体(抗HBs)；第三次接种时有生物学辅助剂的作用，可促进继发应答。

　　与以前的推测不同，为预防乙肝感染，抗体浓度未必维持10mIU/ml以上。从很多研究看，不仅血中实际存有抗体，还可通过B细胞的免疫记忆来确保预防效果。B细胞一旦与抗原接触立即增殖，数日内即可产生足量的特异性抗体。

　　而以前的观点认为，抗体浓度过低的高危人群和基础免疫之后未发现充足的抗体者，需追加接种。如在暴露于乙肝病毒之后，应使用免疫球蛋白被动免疫。

　　至于旅行者、免疫力正常的药物依赖者、精神病病人、或因性行为乙肝病毒高危感染者等，不必追加接种。唯一例外的是，防御系统不正常，免疫记忆不充分的患者，预防接种后每隔6～12个月，如测定抗体浓度低于10mIU/ml，则应追加接种。医务人员有完全基础免疫，则无需追加接种。

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[B]Are booster immunisations needed for lifelong hepatitis B immunity? European Consensus Group on Hepatitis B Immunity[/B]

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Date: Wed, 23 Feb 2000 11:10:31 -0500
From: [email protected]
Subject: Are booster immunisations needed for lifelong hepatitis B immunity? European Consensus Group on Hepatitis B Immunity

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Lancet 2000 Feb 12;355(9203):561-5

Are booster immunisations needed for lifelong hepatitis B immunity? European
Consensus Group on Hepatitis B Immunity.

[Medline record in process]
Long-term protection against clinically significant breakthrough hepatitis B
(HB) virus infection and chronic carriage depends on immunological memory,
which allows a protective anamnestic antibody response to antigen challenge.
Memory seems to last for at least 15 years in immunocompetent individuals.
To date there are no data to support the need for booster doses of HB
vaccine in immunocompetent individuals who have responded to a primary
course. All adequately vaccinated individuals have shown evidence of
immunity in the form of persisting anti-HBs and/or in vitro B-cell
stimulation or an anamnestic response to a vaccine challenge. Nonetheless
several countries and individuals currently have a policy of administering
booster doses to certain risk groups. Boosters may be used to provide
reassurance of protective immunity against benign breakthrough infection.
For immunocompromised patients, regular testing for anti-HBs, and a booster
injection when the titre falls below 10 mIU/mL, is advised. Long-term
monitoring should continue, to confirm the absence of clinically significant
breakthrough episodes of hepatitis B and to find out if a carrier state
develops after 15 years. Also, non-responders to a primary course should
continue to be studied.

PMID: 10683019, UI: 20145224

清照

[B]Are Booster Shots for Hepatitis B Necessary?[/B]


from Medscape Pediatrics


Question
Are booster shots for hepatitis B necessary, and if so, how often should they be given? F. Noorani, MD

Response
from William Cassidy, MD, 03/01/2001

Neither the Advisory Committee for Immunization Practices (ACIP) in the United States nor the European Consensus Group on Hepatitis B Immunity recommends booster doses for most children and adults.[1,2] A postvaccination anti-HBs titer of greater than or equal to 10 mIU/mL is associated with protection against clinically significant HBV infection and is widely accepted as a protective response to vaccination.[3] Concern often arises when HBsAb titers are later found to have waned to less than 10 mIU/mL (ie, below protective levels).
Unlike HBiG, the HBV vaccine induces immunologic memory. In vitro studies show that if the vaccine series initially induces an HBsAb titer of greater than or equal to 10 mIU/mL, then memory B and T cells retain the capacity to generate antibodies upon re-exposure to B surface antigen even if the HBsAb titer falls to less than 10 mIU/mL.[4,5] Clinical trials in infants, adolescents, and adults have shown that, in those successfully immunized, antibody titers remain high and few become carriers in follow-up periods as long as 12 years.[6-9]

Subclinical breakthrough HBV infections have been reported in persons previously vaccinated who live in endemic areas or who live with family members who are chronic carriers.[9,10] In a prospective study, breakthrough infections were detected through HBcAb seroconversion in 1630 vaccinated patients. A total of 13 cases, or 0.8%, were identified over a 10-year follow-up period; none had clinically significant infections.[9] It appears, therefore, that even in those in whom immunologic memory does not completely prevent infection, the infections that do occur are subclinical and do not result in morbidity or mortality.

There is one situation where annual monitoring of HBsAb titers is recommended: renal failure patients and other immunocompromised hosts who are at high risk for HBV exposure.[1,2] If the titer is less than 10 mIU/mL, a booster dose should be given. T helper cell function is compromised in these hosts and therefore immunologic memory is not reliable.




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References
Centers for Disease Control and Prevention. Recommendations of the Advisory Committee on Immunization Practices (ACIP): Use of vaccines and immune globulins in persons with altered immunocompetence. MMWR Morb Mortal Wkly Rep. 1993;42(No. RR-4).1-18. Available at
http://www.cdc.gov/mmwr/preview/ mmwrhtml/00023141.htm
European Consensus Group on Hepatitis B Immunity. Are booster immunisations needed for lifelong hepatitis B immunity? European Consensus Group on Hepatitis B Immunity. Lancet. 2000;355:561-565.
World Health Organization. Thirteenth meeting of Global Advisory Group of EPI. Wkly Epidemiol Rec. 1992;1/2:3-7 and 3:9-12.
Van Hattum J, Maikoe T, Poel J, et al. In vitro anti-HBs production by individual B cells of responders to hepatitis B vaccination who lost anti-HBs. In: Hollinger FJ et al, eds. Viral Hepatitis and Liver Disease. Baltimore: Williams & Wilkins; 1992:774-776.
Leroux-Roels G, Van Hecke E, Michielsen, et al. Correlation between in vivo humoral and in vitro cellular immune responses following immunization with hepatitis B surface antigen (HBsAg) vaccines. Vaccine. 1994;12:812-818.
West DJ, Watson B, Lichtman J, et al. Persistence of immunologic memory for twelve years in children given hepatitis B vaccine in infancy. Pediatr Infect Dis J.1994;13:745-747.
Wu JS, Hwang L-Y, Goodman KJ, Beasley RP. Hepatitis B vaccination in high-risk infants: 10-year follow-up. J Infect Dis. 1999;179:1319-1325.
Cassidy WM, Watson B , Ioli V, et al. A randomized trial of alternative 2 and 3-dose hepatitis B vaccination regimens in adolescents: antibody responses, safety, and immunologic memory. Pediatrics. In press.
Wainwright RB, Bulkow LR, Parkinson AJ, et al. Protection provided by hepatitis B vaccine in a Yupik Eskimo population: results of a 10 year study. J Infect Dis. 1997;175:674-677.
Shih HH, Chang MH, Hsu HY, Lee PI, Ni YH, Chen DS. Long term immune response of universal hepatitis B vaccination in infancy: a community-based study in Taiwan. Pediatr Infect Dis J. 1999;18:427-432.
About the Panel Members
Associate Professor of Medicine, Department of Internal Medicine, Earl K. Long Medical Center, Louisiana State University Health Sciences Center, Baton Rouge, Louisiana.

天狼星

如果这个推理能够得到临床确证意义很大的。
唯一例外的是，防御系统不正常，免疫记忆不充分的患者，预防接种后每隔6～12个月，如测定抗体浓度低于10mIU/ml，则应追加接种。
   这个问题，在现实中有 反复接种疫苗但形成不了抗体，或者抗体有消失的，是这种情况吗？这种情况多吗？占什么的比例？

清照

免疫系统不健全的状况，在现实中肯定有，但是我也不知道这样的情况有占多大比例的确切数字。从这几年观察总结的统计数字来看，大约接种乙肝疫苗后表面抗体产生率达90-95%以上，不同人群有较大差异。一般产生抗体率：婴幼儿>青年人>老年人>免疫系统有缺陷的病人。



[B]乙肝疫苗要不要复种？[/B]

庄辉  

　　接种乙肝疫苗后要不要复种？何时复种？其免疫保护期有多长？这是大家关心的问题。我国对广西隆安县接种过乙肝疫苗的儿童15年随访观察表明，接种组乙肝表面抗原阳性率为1.9%，对照组为16.7%，保护率为88.6%，15年时接种组50.9%乙肝抗体阳性。说明乙肝疫苗的免疫持久性可长达15年。国外也有类似报道。非洲塞内加尔接种乙肝疫苗后12年，疫苗组儿童乙肝表面抗原阳性率为2%，对照组为19%，保护率为88%，接种乙肝疫苗的儿童中68%有乙肝抗体。接种乙肝疫苗后，虽然随着时间延长，接种者的抗体水平逐年下降，但当他们受到乙肝病毒攻击时，由于免疫记忆作用，抗体水平可再度升高。这在乙肝高发区和高危人群中尤为明显。因此，从总体来说，如果是全程乙肝疫苗接种，并于接种后产生了高滴度的乙肝抗体，则在10年内可不复种。

　　但从个体来说，每个接种者的情况可能不同，因此，对具体情况应作具体分析。例如，最近一次全国乙肝疫苗接种率调查表明，我国全程合格接种率仅为28.4%，73.6%为非全程接种。非全程接种的儿童可能无乙肝抗体或抗体滴度较低，对此类儿童应检测乙肝抗体，如抗体未产生或已消失，则应及时复种。值得指出的是：即使接种全程乙肝疫苗，也有5%～10%接种者不产生乙肝抗体或只产生低滴度的抗体，对这些无应答或低应答的儿童应多次接种乙肝疫苗直至抗体产生。此外，对一些感染乙肝病毒几率高的儿童，例如在其父母或家庭成员中有乙肝病毒携带者，则应定期监测其抗体水平和乙肝感染指标，一旦抗体降至低水平或完全消失，则应及时复种。

（ZT自健康报）

youyu

确实，主动免疫的特点，是有记忆效应，虽然抗体滴度下降，但一旦接触到抗原，会激发免疫系统。

复种只是安全起见，可能考虑到人体的免疫在某些时候可能会产生紊乱，有足够滴度的抗体，更安全些。

[此贴子已经被作者于2003-10-31 19:28:48编辑过]

清照

[B]关于疫苗的保护率[/B]

中华肝脏病杂志，2003年第11卷第4期：203
  
[B]新生儿乙型肝炎疫苗普遍接种的长期免疫效果[/B]

龚健 李荣成 杨进业 李艳萍 陈修荣 徐志一 刘崇柏 曹惠霖 赵铠 倪道明
  
【摘要】 目的 观察新生儿乙型肝炎(简称乙肝)疫苗普遍接种预防儿童期乙型肝炎病毒（HBV）感染的长期免疫效果和对儿童乙肝发病的影响。 方法 1986年起在乙肝高发区隆安县实施不筛检母亲HBsAg、新生儿普遍接种常规剂量乙肝疫苗的免疫方案。采用出生队列定群随访、横断面调查和监测乙肝发病情况的方法对血源乙肝疫苗和重组酵母乙肝疫苗的保护效果进行观察。 结果　血源乙肝疫苗免疫后1～13年HBsAg阳性率为0.7%～2.9%，平均1.7%，保护率为83.5%～96.6%，HBV感染率为1.1%～5.1%，平均2.4%，保护率为93.5%～98.4%。重组酵母乙肝疫苗免疫儿童的HBsAg阳性率为1.8%～2.4%，平均2.0%，保护率为78.4%～85.2%。免疫实施14年后, 1～14岁人群乙肝发病率为1.5/10万，比历史对照同龄者减少了91.8%；未免疫儿童发病率为14.4/10万，与历史对照差异无显著性，免疫儿童中无乙肝病例发生，保护率为100%。 结论 [B]新生儿乙肝疫苗免疫后13年内不必加强免疫[/B]，重组酵母乙肝疫苗与血源性乙肝疫苗的保护效果相似，乙肝疫苗预防作用已初见成效。

【关键词】 肝炎疫苗,乙型； 肝炎表面抗原，乙型