孩尔来福甲型肝炎灭活疫苗不同免疫程序的评价

为评价孩尔来福 (Healive○R)甲型肝炎 (甲肝 )灭活疫苗不同免疫程序的免疫原性 ,在山区农村的 5个村 ,对 16 7名 5～ 11岁甲肝易感儿童 ,分 5组以 0、1,0、3,0、6 ,0、12个月程序接种Healive○R甲肝灭活疫苗 (2 5 0U/剂 ) ,对照组以0、6个月程序接种HavrixTM72 0EIU甲肝灭活疫苗。结果显示 :Healive○R甲肝灭活疫苗初次免疫 (初免 )后 2周、4周抗甲肝病毒抗体 (抗 HAV)阳转率分别为 97 0 %和 95 5 % ,几何平均滴度 (GMT)分别为 35 5mIU/ml和 2 5 1mIU/ml;初免后 3、6、12个月的抗 HAV阳转率均为 10 0 0 % ;GMT则分别为 4 17mIU/ml、391mIU/ml和 36 1mIU/ml。各程序组全程免疫后 1个月抗 HAV阳转率均为 10 0 0 % ;GMT则分别为 14 893mIU/ml(0、12个月 ) >5 96 3mIU/ml(0、6个月 ) >32 6 5mIU/ml(0、3个月 ) >1973mIU/ml(0、1个月 ) ,差异有非常显著的统计学意义。HavrixTM 甲肝灭活疫苗初免后 4周、6个月和全程免疫后 1个月 ,抗 HAV阳转率分别为 71 0 %、71 0 %和 10 0 0 % ,GMT为 15 8mIU/ml、15 2mIU/ml和 110 4mIU/ml。免疫 1剂Healive○R甲肝灭活疫苗GMT可达有效保护水平的 12倍以上。 0、1个月程序可用于特殊人群的加速免疫 ,0、3,0、6 ,0、12个月程序可根据不同人群的需求而灵活应用 ,以 0、1     

孩尔来福甲型肝炎灭活疫苗接种乙型肝炎病毒表面抗原阳性儿童的研究

为进一步观察孩尔来福 (Healive)甲型肝炎 (甲肝 )灭活疫苗在乙型肝炎病毒表面抗原 (HBsAg)阳性儿童中接种的安全性和免疫原性 ,于 2 0 0 1年在平山县农村 ,将 4 2例HBsAg阳性儿童随机分为 4组 ,分别按照 0、1,0、3,0、6 ,0、12个月程序接种Healive甲肝灭活疫苗 ,观察初免和全程免疫后的局部和全身反应 ,检测初免及全程免疫后 1个月血清抗甲肝病毒抗体 (抗 HAV)阳转率和滴度。结果显示 :初免和全程免疫后 72h内均未见局部和全身反应 ,亦无丙氨酸氨基转移酶 (ALT)异常 ;4个组初免后 1个月 ,抗 HAV阳转率均达 10 0 0 % ,抗体几何平均滴度 (GMT)为173mIU/ml～ 318mIU/ml,其差异无显著的统计学意义 (t=1 2 0 4 ,P >0 0 5 )。全程免疫后 1个月 ,0、12 ,0、6 ,0、3,0、1个月免疫程序组GMT分别为 192 99mIU/ml、4 30 1mIU/ml、2 74 9mIU/ml、172 5mIU/ml,与同龄健康易感儿童按相同免疫程序的免疫效果规律一致。全程免疫后 1个月 ,HBsAg阳性儿童和健康儿童抗 HAVGMT的差异无显著的统计学意义 (P >0 0 5 )。表明HBsAg对Healive甲肝灭活疫苗的免疫应答无干扰 ;HBsAg阳性儿童接种Healive甲肝灭活疫苗是安全和有效的。     

孩尔来福甲型肝炎灭活疫苗在儿童中应用的安全性和免疫原性观察

为探讨孩尔来福 (Healive)甲型肝炎 (甲肝 )灭活疫苗在儿童中应用的安全性和免疫原性 ,选择 2～ 15岁抗甲肝病毒抗体 (抗 HAV)阴性健康易感儿童 91名作为接种对象 ,采用 0、6个月程序接种Healive甲肝灭活疫苗 2 5 0U/剂 ,观察免疫后的局部和全身不良反应 ,并于全程免疫后 1个月检测抗 HAV阳转率和抗体几何平均滴度 (GMT)。结果显示 :91名观察对象在接种第 1针和第 2针后均未见严重不良反应 ,仅在 8～ 72h出现轻微的一过性局部和全身轻度发热反应。全程免疫后 1个月抗 HAV阳转率为 10 0 % ,抗体GMT为 14 4 0 7mIU/ml。表明Healive甲肝灭活疫苗在儿童中应用具有良好的安全性和免疫原性 ,采用 0、6个月免疫程序可获得高滴度抗体。     

孩尔来福甲型肝炎灭活疫苗小剂量免疫效果研究

为制定孩尔来福 (Healive)甲型肝炎 (甲肝 )灭活疫苗在儿童中免疫的最佳剂量和最佳程序 ,在河北省某山区农村筛选 5～ 15岁的甲肝易感儿童 2 0 6人 ,随机分为 6组 ,分别接种 5 0 0U/剂和 2 5 0U/剂 ( 0、1个月 ,0、3个月和 0、6个月程序 )甲肝灭活疫苗 ,观察初免和加强免疫后局部和全身反应 ;检测免疫后 2周、3周、4周及 3、4、6、7个月的甲肝抗体 (抗 HAV)阳转率和抗体水平。结果显示 :Healive甲肝灭活疫苗副反应呈轻微的一过性局部和全身反应 ;5 0 0U/剂和 2 5 0U/剂初免后 2周 ,抗 HAV阳转率分别为 97 4%和 97 0 %,抗体几何平均滴度 (GMT)分别为371mlU/ml和 35 5mlU/ml;全程免疫后各剂量 /程序组抗 HAV阳转率均为 10 0 0 %,2 5 0U/剂 0、1个月 ,0、3个月和0、6个月程序组抗 HAV滴度分别为 1973mlU/ml、3 2 6 5mlU/ml和 5 96 3mlU/ml,以 0、6个月程序组最高 ,差异有显著的统计学意义。表明Healive甲肝灭活疫苗安全、高效 ;0、1个月程序可对特殊人群进行免疫预防 ;2 5 0U/剂 0、6个月程序是儿童的适宜剂量和免疫程序。     

国产甲型肝炎灭活疫苗低剂量的免疫原性研究

为了观察国产甲型肝炎(甲肝)灭活疫苗低剂量多针次的免疫效果,在平山县2个农村筛选4～10岁甲肝病毒抗体(抗-HAV)阴性的65名易感儿童,以自然村随机分为2组,分别接种125U/剂(0、1、6个月)和250U/剂(0、6个月)唐山怡安生物工程有限公司研制的甲肝灭活疫苗,观察免疫后局部反应和全身反应;检测免疫后1、6、7个月的血清抗-HAV阳转率和滴度.结果显示两种剂量疫苗免疫后无严重的局部和全身副反应.125U/剂和250U/剂初免后,抗-HAV阳转率分别为62.5%和93.9%,几何平均滴度(GMT)分别为342mIU/ml和382mIU/ml;6个月阳转率均为100.0%,GMT分别为531mIU/ml和391mIU/ml;全程免疫后1个月GMT分别为3170mIU/ml和5963mIU/ml.表明国产甲肝灭活疫苗125U适于儿童使用,并可作为研究甲、乙肝联合疫苗的参考剂量.     

国产甲型肝炎灭活疫苗在低龄儿童中应用的安全性和免疫原性研究

目的 探讨国产甲型肝炎灭活疫苗在低龄儿童（1－4岁）中应用的安全性和免疫原性。方法 选1－4岁易感健康儿童63名，随机分为两组，按0，3和0，6程序接种国产甲肝灭活疫苗500U／剂，观察免疫后的局部和全身反应，并检测初免后及全程免疫后的抗－HAV阳转率和抗体GMT。结果 初免和加强免疫后有轻微的过性局部和全身反应，未见肝功异常。初免后1、3、6个月抗体阳转率分别为85.7%、88.5%和83.8%；抗体GMT玢别为182mU/ml、225mU/ml和252mU/ml；0，3和0，6程序全程免疫后1个月抗体阳转率均为100％；抗体GMT分别为2718mU/ml和4683mU/ml。结论 国产甲肝灭活疫苗在低龄儿童中应用具有良好的安全性和免疫原性；接种两剂可获高滴度甲肝抗体；0，6程序优于0，3程序。     

国产甲型肝炎灭活疫苗在儿童中应用的安全性免疫原性和免疫程序研究

为了评价国产甲型肝炎(甲肝)灭活疫苗在儿童中应用的安全性、免疫原性和免疫程序,在河北省某地山区农村筛选5～15岁的甲肝易感儿童275人,以村为单位,随机分为4组,分别接种1 000U/剂和500U/剂(0、3个月和0、6个月程序),观察初种和加强免疫后局部反应和全身反应,检测免疫后1、3、4、6、7个月的血清抗甲肝病毒抗体(抗-HAV)阳转率和滴度.结果显示国产甲肝灭活疫苗无严重的局部及全身反应,1 000U/剂和500U/剂初免后1个月抗-HAV阳转率分别为93.8%和90.6%,抗体滴度分别为174mIU/ml和146mIU/ml;全程免疫后1个月各组抗体阳转率均为100.0%,1 000U组和500U组抗-HAV滴度分别为7 540mIU/ml、4 535mIU/ml;500U组0、6个月和0、3个月程序免疫后抗-HAV滴度分别为4 535mIU/ml和3 269mIU/ml,两组比较差异有极显著的统计学意义.表明国产甲肝灭活疫苗在儿童中应用是安全、有效的,500U/剂适用于儿童,免疫程序以0、6个月为佳.     

孩尔来福甲型肝炎灭活疫苗单剂接种安全性与免疫效果观察

为探讨孩尔来福 (Healive○R)甲型肝炎 (甲肝 )灭活疫苗在人群中应用的安全性和免疫原性 ,选择 2 4～ 36月龄、18～ 2 5岁 2组人群 ,分别接种Healive○R甲肝灭活疫苗 2 5 0U、5 0 0U1针 ,观察免疫后的局部和全身反应 ,并检测儿童免疫后 6周抗体阳转率和抗体几何平均滴度 (GMT)。结果发现 :接种后仅个别人有轻微的一过性全身反应 ,抗体阳转率为 94 5 2 % ,抗体GMT为 2 6 0 3mIU/ml。显示Healive○R甲肝灭活疫苗在人群中接种具有良好的安全性和免疫原性。     

倍尔来福TM甲乙型肝炎联合疫苗在成人中应用的安全性和免疫原性研究

为评价倍尔来福TM甲、乙型肝炎联合疫苗在成人中应用的安全性和免疫原性 ,在广西壮族自治区和河北省以16～ 2 0岁中学生为研究对象 ,按抗甲型肝炎 (甲肝 )病毒抗体 (抗 HAV )和乙型肝炎 (乙肝 )病毒 (HBV)感染 5项指标均阴性 ,抗 HAV阴性和HBV感染 5项指标阴性或阳性 ,HBV感染 5项指标阴性、抗 HAV阴性或阳性 ,分为AB组、A组和B组 ,按 0、1、6个月程序分别接种甲、乙型肝炎联合疫苗 ,甲肝灭活疫苗和重组 (酵母 )乙肝疫苗。疫苗剂量为每剂含HAV抗原 5 0 0U和乙肝病毒表面抗原 10 μg。观察接种疫苗后 72h内局部反应和全身反应 ,检测免疫后 2个月和7个月的血清抗 HAV阳转率、乙肝病毒表面抗体 (抗 HBs)保护率及抗体滴度。结果表明 :AB组局部副反应主要为—过性疼痛 ,全身副反应以低热为主 ,并在 72h内自行恢复。免疫后 7个月 ,AB组与A组抗 HAV阳转率均为 10 0 % ;几何平均滴度 (GMT)分别为 2 2 6 6 3mIU/ml和 2 3311mIU/ml;抗 HBs保护率AB组和B组分别为 97 71%和 96 89% ;GMT分别为 10 7mIU/ml和 97mIU/ml,两组阳转率、保护率及GMT差异均无显著的统计学意义。因此 ,在成人中应用甲、乙型肝炎联合疫苗与单价甲肝灭活疫苗和单价重组 (酵母 )乙肝疫苗具有相同的安全性和免疫原性。     

成人和儿童接种国产甲型肝炎灭活疫苗的安全性与免疫原性的初步观察

为了评价国产甲型肝炎 (甲肝 )灭活疫苗的安全性和免疫原性 ,将 176名健康易感儿童和 2 0 6名成人随机分为 4组 ,10 7名儿童 (A组 )和 131名成人 (B组 )接种国产甲肝灭活疫苗 ,另 6 9名儿童 (C组 )和 75名成人 (D组 )作为对照接种史克必成公司生产的甲肝灭活疫苗。国产疫苗剂量为儿童 6 4 0EU/1 0ml,成人 12 80EU/1 0ml;对照疫苗剂量儿童 72 0EIU/1 0ml,成人 14 4 0EIU/1 0ml,均采用 0、6个月免疫程序。观察 72h内局部和全身反应 ,免疫后 1、6、7个月的免疫应答水平。结果显示 :所有接种对象均未出现明显的局部和全身副反应 ,亦未发现免疫后丙氨酸氨基转移酶 (ALT)升高。初次免疫后 1个月 ,A组和B组抗体阳转率分别为 94 8%和 96 7% ,几何平均滴度(GMT)为 75 8 6mIU/ml和 36 30 8mIU/ml。全程免疫后 1个月 ,4个组抗体阳转率均为 10 0 % ,A组和B组抗体GMT升至 10 4 71 2mIU/ml和 12 30 2 7mIU/ml,略高于对照的C组和D组 (分别为 30 90 3mIU/ml和3388 4mIU/ml)。表明国产甲肝灭活疫苗具有良好安全性和免疫原性。     

国产甲肝减毒活疫苗(IA-1株)与进口甲肝灭活疫苗的2年免疫效果比较

目的　比较国产甲肝减毒活疫苗和进口甲肝灭活疫苗免疫效果。方法　在广西柳城县筛选出 6～ 1 2岁甲肝易感儿童 2 1 7人 ,以个体随机分为 4个组。B、C组接种国产甲肝减毒活疫苗 (LA - 1株 ,滴度 1 0 6 75 TCID5 0 ) ,接种程序分别为 0 - 6和 0 - 1 2 ;D组接种低滴度国产甲肝减毒活疫苗 (LA - 1株 ,滴度 1 0 6 0 TCID5 0 ) ,E组接种史克公司市售甲肝灭活疫苗 (贺福立适 ,72 0E1 .U) ,接种程序均为 0 - 6。各组于第 1针免后 1 ,6 ,1 2 ,2 4个月 ,第 2针免后 1个月采血 ,用美国ABBOTT公司的ImxmEIA试剂 ,检测甲肝抗体IgG。 结果　滴度 1 0 6 75 TCID5 0 的国产减毒活疫苗两种程序 ,除 0 - 6程序组在第 2针免后 1个月的抗体水平峰值较低外 ,其余各次随访的抗体反应结果均与进口甲肝灭活疫苗相似。低滴度减毒活疫苗 ( 1 0 6 0 TCID5 0 )的抗体阳性率和抗体水平均低于其他各组。结论　滴度 1 0 6 75 TCID5 0 国产甲肝减毒疫苗与进口甲肝灭活疫苗免疫效果相近 ,具有良好的免疫原性和很好的回忆反应 ,加强免疫可以提高疫苗的保护效果和延长保护年限。     

甲型肝炎减毒活疫苗加强免疫效果的初步研究

目的　观察甲型肝炎 (甲肝 )减毒活疫菌 (10 7.0 TCID50 )加强免疫效果 ,并同活疫苗一针法结果进行比较。方法　在河北省正定县选择 42名经事先检测甲肝抗体阴性的易感儿童 ,分别于0、2和 6个月各接种一剂甲肝减毒活疫苗 ,并于接种后 1、2、6、7、9和 12个月采集血清标本 ,观察免后抗体动态变化。结果　第 1剂接种后 1个月抗体阳转率达 81.4% ,第 2剂免后抗体阳转率达 10 0 % ,抗体水平于第 3剂免后 1个月达高峰 ,为 2 739mIU/ml,以后呈下降趋势 ,免后 12个月抗体阳转率仍为 10 0 % ,抗体水平下降至 979mIU/ml。结论　甲型肝炎减毒活疫苗加强免疫能诱导良好的免疫回忆反应 ,其免疫学效果同史克灭活疫苗相当 ,而明显高于活疫苗一针法。活疫苗加强免疫中 ,初免是基础。活疫苗加强免疫会提高疫苗保护效果 ,并延长疫苗的免疫持久性     

Immunogenicity and safety of three consecutive lots of a new preservative-free inactivated hepatitis A vaccine (Healive): a double-blind, randomized and controlled trial

Immunization is considered as the most effective way for the prophylaxis of hepatitis A virus (HAV) infection. This study aimed to evaluate the immunogenicity and safety of three consecutive lots of a new preservative-free inactivated hepatitis A vaccine (Healive) in healthy children. A double-blind, randomized and controlled clinical trial was conducted in healthy volunteers aged from 1 to 8 years. Total 400 subjects were enrolled and assigned into four groups, receiving one of the three lots of Healive or an established control vaccine. The vaccination was two-dose regimen with 6 months apart. Anti-HAV titers were determined at the 1st, 6th and 7th month. The results showed that Healive was highly immunogenic in children with 100% seroconversion rate (SR) and 3237-3814 mIU/ml geometry mean titer (GMT) 1 month after the second dose. The immunogenicity of Healive was statistically higher than that of the control vaccine with respect to GMT and SR (P=0.037 to P<0.001). Both Healive and control vaccine were well tolerated with 1-5% incidence of overall adverse reactions (P>0.298). Severe adverse reaction was not reported. Both SRs (1, 6 and 7 months) and GMTs (1 and 7 months) in subjects receiving one of the three consecutive lots of Healive had not statistical difference (P=0.114-0.710), suggesting that Healive was well consistent. The immune responses in younger children (1-3 years) and older children (4-8 years) were similar to each other (P=0.187-0.963). The present study indicated that Healive was greatly consistent between production lots, well tolerated and highly immunogenic in children, which made the preservative-free inactivated hepatitis A vaccine well suitable for inclusion in the routine programme of children vaccination.     

Safety and immunogenicity of hepatitis A vaccine in infants: a candidate for inclusion in the childhood vaccination programme

Forty-eight infants received a single dose (720 ELISA units = 0.5 ml) of inactivated hepatitis A vaccine at the fifth month of age with booster at the 11th month of age, together with the second and third doses of the vaccines compulsory under Italian law (diphtheria, tetanus, oral polio and hepatitis B). Overall, the seroconversion rate was 100%. The anti-HAV geometric mean titre (GMT) reached 3,021 mIU/ml in infants born to anti-HAV-negative mothers, but only 399 mIU/ml in infants born to anti-HAV-positive mothers. Hepatitis A vaccine was immunogenic, safe and well tolerated without significant side-effects. There seems to be no reason for not including it in childhood vaccination programmes particularly in low endemic HAV areas.     

Comparison of immunogenicity of two hepatitis A vaccines--VAQTA and HAVRIX--in young adults.

Two new hepatitis A vaccines have been developed, and their immunogenicity tested using different immunoassays. The present study was designed to compare the immunogenicity of these two hepatitis A virus (HAV) vaccines--VAQTA and HAVRIX--as determined by seroconversion rates and anti-HAV titers, and using the same immunoassay. Healthy volunteers (15-30 y), seronegative for anti-HAV, were randomized in an open single center study to four groups of 20-21 vaccinees each, to receive either a 25 U or a 50 U dose of VAQTA, or HAVRIX at 720 EU or 1440 EU/dose, administered at 0, 1 and 6 m or at 0 and 6 m, respectively. Four weeks after primary immunization, seroconversion rates were 100% for VAQTA and 95% for HAVRIX, following injection of 50 U or 1440 EU, respectively (p = NS) and anti-HAV GMTs were 40 and 37 mIU/ml for VAQTA and HAVRIX, respectively. At 6 months, prior to the booster dose, seroconversion rates were 100% for both vaccines, with anti-HAV GMTs of 111 and 70 mIU/ml for VAQTA and HAVRIX, respectively (P < 0.05). At month 7, four weeks after the only booster injection, using the two dose regimen, anti-HAV titers were 2212 and 1511 mIU/ml for VAQTA and HAVRIX, respectively (P < NS). Using three doses of 25 U/dose of VAQTA or 720 EU/dose of HAVRIX at 0, 1 and 6 m did not produce any clinically evaluable advantage over the two dose regimen for either vaccine. No significant adverse events were observed using either vaccine. In summary, both vaccines have similar immunogenicity demonstrated using identical immunoassays for evaluation. These results also confirm the outstanding immunogenicity of a single dose of either of the HAV vaccines and support their use in pre- and possibly postexposure prophylaxis against hepatitis A virus infection.     

倍尔来福TM甲、乙型肝炎联合疫苗安全性和免疫原性研究

目的 观察倍尔来福~(TM)甲、乙型肝炎(甲、乙肝)联合疫苗的安全性和免疫原性。方法以高中一年级(成人组)和小学1～5年级(儿童组)学生为研究对象,按对甲、乙肝病毒均易感、只对甲肝病毒易感和只对乙肝病毒易感分为AB组、A组和B组,按0、1和6个月三剂程序分别接种甲、乙肝联合疫苗、灭活甲肝疫苗和重组乙肝疫苗。疫苗剂量成人组每剂含甲肝病毒抗原500U和(或)HBsAg10μg,儿童组减半。疫苗接种后72h内观察副反应,免疫后2、7个月采集血清标本检测抗-HAV和抗-HBs。结果 儿童AB组和成人AB组局部副反应发生率分别为0.58％(2/344)和2.56％(8/312),全身副反应发生率分别为9.88％(34/344)和5.45％(17/212),与对照组相比差异无显著性。局部反应主要是轻度疼痛,全身反应主要是低热。免疫后7个月,两组抗-HAV阳转率均为100％,与A组相同;抗体滴度(GMT)分别为33 910mIU/ml和23 435 mIU/ml,显著高于A组;两组抗-HBs阳转率分别为97.30％和96.63％;GMT为103 mIU/ml和102 mIU/ml,抗-HBs阳转率及GMT均与B组差异无显著性。结论 倍尔来福~(TM)甲、乙肝联合疫苗与单价甲肝灭活疫苗和单价重组乙肝疫苗具有相同的安全性和免疫原性。     

Immunological priming of one dose of inactivated hepatitis A vaccine given during the first year of life in presence of maternal antibodies

BACKGROUND: In hepatitis A virus (HAV)-seronegative infants, inactivated hepatitis A vaccines are highly immunogenic. On the contrary, in infants who are HAV-seropositive before vaccination, the interfering effect of passively-transferred maternal anti-HAV antibodies leads to lower post-primary immunization anti-HAV levels, as compared to those achieved by seronegative infants. One possible way to overcome this drawback is to delay hepatitis A vaccination later during the first year of life. The objective of the study was to document the immunogenicity of an inactivated hepatitis A vaccine in 6 months old HAV-seropositive infants, given as two dose regimen consisting of a single primary immunization at 6 months of age, followed by a booster dose 6 months later. METHODS: The immunogenicity of one hepatitis A vaccine (Avaxim pediatric, Aventis Pasteur) was documented in 108 6 months old, HAV-seropositive infants randomly assigned to receive one priming dose of hepatitis A vaccine either concomitantly with (Group 2) or 2 weeks after the third dose of routine diphteria-tetanus-whole cell pertussis reconstituting lyophilized tetanus conjugated Haemophilus influenzae type b (DTwcP//PRP approximately T) vaccine and oral poliomyelitis vaccine (OPV) (Group 1). A booster dose was given 6 months later, concomitantly with MMR vaccine. RESULTS: The 91 infants who were HAV-seropositive (ELISA titer >20 mIU/ml) at the moment of primo vaccination remained seropositive 1 month later. Geometric mean titers (GMT) decreased from 292 and 278 mIU/ml 1 month after the first dose, to 77.6 and 76.0 mIU/ml 6 months after, in Groups 1 and 2, respectively. Post-booster titers increased markedly in both groups, with GMTs of 1731 and 1866 mIU/ml and geometric mean post/pre-immunization titer ratios of 22.3 and 24.6, respectively. CONCLUSIONS: These results suggest that immunological priming induced by a single dose of Avaxim pediatric administered to 6 or 6.5 months old, HAV-seropositive infants is present and should not preclude the use of this vaccine in such populations.     

Immunogenicity of two paediatric doses of monovalent hepatitis B or combined hepatitis A and B vaccine in 8-10-year-old children

Hepatitis A and B vaccines are highly immunogenic in three-dose schedules. To obtain an equivalent result in children with two paediatric doses would be of significant benefit. The purpose of this study was to measure the immunogenicity of a two-dose schedule in children with two licensed recombinant HBsAg containing vaccines given at paediatric doses, one of them combined with hepatitis A. Seven-hundred and four healthy school children aged 8-10 years were recruited in an open label study to receive either Twinrix Pediatric (360 El.U HAV antigen; 10 microg HBsAg) or Recombivax (2.5 microg HBsAg) vaccine intramuscularly 6 months apart. The seroconversion (>/=1 mIU/ml for anti-HBs antibodies and >/=33 mIU/ml for anti-HAV antibodies), seroprotection (anti-HBs >/=10 mIU/ml) rates and the geometric mean titers (GMTs) were determined 4-8 weeks after the second dose. The anti-HBs seroconversion rate was 97.1% with Twinrix and 97.2% with Recombivax. The seroprotection rates were 96.5 and 94.4%, respectively (P = 0.17). The GMT was higher with Twinrix than with Recombivax (3248 mIU/ml versus 742 mIU/ml, P < 0.0001). All the children vaccinated with Twinrix seroconverted to HAV and the GMT was 5168 mIU/ml. The obtained results suggest that two paediatric doses of hepatitis vaccines are highly immunogenic in 8-10-year-old children. This schedule could facilitate a greater vaccine acceptance and the addition of hepatitis A vaccine to existing adolescent universal hepatitis B virus immunization programs.