水痘减毒活疫苗首剂免疫持久性及加强免疫效果分析

目的观察儿童水痘减毒活疫苗(VarV)首剂接种后免疫持久性和加强免疫的效果,为实施加强免疫防控水痘疫情提供参考。方法选择657名接种过1剂次国产或进口VarV的2~7岁儿童分别在首剂接种后间隔1、3、5年加强免疫1剂次国产VarV,检测和比较加强免疫前后血清中水痘Ig G抗体水平。结果 VarV首剂免疫后1、3、5年抗体阳性率分别为93.9%、88.6%、88.9%(x~2=4.33,P=0.115),抗体GMT分别为1∶11.06、1∶7.57、1∶8.22(F=9.25,P0.001);国产和进口VarV的抗体阳性率或GMT均无显著性差异。首剂接种后间隔1、3、5年加强免疫后抗体阳转率分别为76.9%、92.4%、95.7%(x~2=41.94,P0.001);抗体GMT分别为1∶86.18、1∶112.54和1∶139.12(F=12.64,P0.001),均显著高于加强免疫前水平。结论国产和进口VarV免疫持久性相当,VarV抗体水平随时间衰减,国产VarV加强免疫效果良好,建议VarV首剂接种后间隔3年加强1剂次VarV。     

3~11岁儿童接种新型冠状病毒灭活疫苗的免疫原性研究

目的 评价3~11岁儿童完成新型冠状病毒（新冠病毒）疫苗基础免疫28~42 d后对原始株的免疫原性及与新冠病毒变异株的交叉免疫反应。方法 于2022年1-7月在山东省乳山市招募3~11岁已按照（0,28）d免疫程序完成2剂新冠病毒灭活疫苗基础免疫的受试者,基础免疫后28~42 d采集静脉血3 ml,检测原始株、Beta、Gamma和Delta变异株的中和抗体水平,计算中和抗体阳性率和GMT。结果 纳入免疫原性分析共395人,其中3~5岁组212人,6~11岁组183人。受试者完成基础免疫后28~42 d,血清中对原始株、Beta、Gamma和Delta变异株的中和抗体阳性率分别为100.00%、74.68%、99.24%和97.22%,年龄组间差异无统计学意义（P>0.05）。受试者完成基础疫苗后28~42 d,血清中对原始株、Beta、Gamma和Delta变异株的中和抗体GMT分别为168.19、10.51、53.65和31.10,年龄组间差异无统计学意义（P>0.05）。结论 在3~11岁儿童中接种2剂新冠病毒灭活疫苗的免疫原性良好,可对新冠病毒变异株产生一定的交叉保护。     

国产冻干水痘减毒活疫苗加强免疫的免疫原性和安全性观察

目的比较国产冻干水痘减毒活疫苗(Var V-FD)加强免疫的免疫原性和安全性,为制定加强免疫策略提供依据。方法选择完成水痘减毒活疫苗(Var V)初次免疫的1 084例1~7岁健康儿童分组观察间隔3个月、1年、3年和5年加强免疫后的水痘抗体水平和不良反应。结果共968名(89.30%)受试者纳入分析。受试者Var V初次免疫后间隔3个月、1年、3年、5年水痘抗体阳性率分别为99.35%、93.90%、88.14%和89.05%(χ2=33.80,P0.001);抗体GMT分别为1∶30.05、1∶11.11、1∶7.50和1∶8.21(F=121.75,P0.001)。抗体阳性率和GMT随着免疫间隔时间延长呈下降趋势(χ2=29.15,P0.001;F=333.94,P=0.003)。间隔3个月、1年、3年、5年加强免疫后,水痘抗体阳转率分别为32.69%、77.00%、92.37%和95.71%(χ2=336.31,P0.001),其中间隔3年与5年组之间无显著性差异,其余各组间均有显著性差异;抗体GMT分别为1∶49.67、1∶86.99、1∶114.15和1∶138.55(F=58.92,P0.001),均显著高于加强免疫前水平,其中间隔3年与5年组之间无显著性差异,其余各组之间均有显著性差异。加强免疫后抗体阳转率和GMT随着免疫间隔时间延长呈上升趋势(χ2=57.26,P0.001;F=189.55,P=0.005)。各组加强免疫后不良反应率分别为12.00%、8.22%、5.93%和5.88%(χ2=9.36,P=0.025),未观察到严重不良反应。结论国产Var V-FD在Var V初次免疫后不同间隔时间进行加强免疫均具有良好的免疫原性和安全性,推荐Var V初次免疫后间隔3年加强免疫1剂次。     

水痘减毒活疫苗加强免疫与乙脑减毒活疫苗联合接种的免疫原性和安全性观察

目的了解水痘减毒活疫苗加强免疫与乙脑减毒活疫苗联合接种的安全性和有效性,为科学制定相关免疫策略提供依据。方法选择425名约24月龄儿童,分为单独接种水痘疫苗组以及联合接种水痘和乙脑疫苗组,分析加强免疫前后水痘抗体水平和疫苗接种安全性。结果加强免疫前,单独接种组以及联合接种组的水痘抗体阳性率分别为93.90%和100.00%,差异有统计学意义(χ~2=12.113,P0.001)。联合接种组的水痘抗体GMT高于单独接种组(t=-7.133,P0.001)。加强免疫后,2组的水痘抗体阳性率均为100.00%。单独接种组的水痘抗体阳转率高于联合接种组(χ~2=24.589,P=0.001)。2组的水痘抗体GMT差异无统计学意义(t=1.662,P=0.097)。单独接种组和联合接种组的不良反应发生率分别为9.52%和12.95%,组间差异无统计学意义(χ~2=1.255,P=0.263),未观察到严重不良事件。结论适龄儿童单独接种水痘疫苗或同时接种水痘与乙脑疫苗均具有良好的免疫原性和安全性。     

不同毒株制备的腮腺炎疫苗的免疫效果分析

目的了解不同毒株制备的腮腺炎减毒活疫苗的免疫效果,为计划免疫接种疫苗种类的选择提供依据。方法选定广州市东山区1~2岁组未免疫及未患过腮腺炎儿童,分别接种国产S79株、Jeryl-Lynn株、Jeryl-Lynn衍生株腮腺炎减毒活疫苗,开展免疫成功率监测。结果接种国产S79株腮腺炎减毒活疫苗92人,抗体阳性率为54·35%(50/92),GMT为1∶10.43;接种Jeryl-Lynn株疫苗62人,抗体阳性率为91.94%(57/62),GMT为1∶17.72;接种Jeryl-Lynn衍生株疫苗70人,抗体阳性率为90.00%(63/70),GMT为1∶18.72。各组抗体阳性率比较差异有统计学意义(χ2=39.68,P<0.01)。各组抗体几何平均滴度比较,差异有统计学意义(F=13.571,P<0.01)。结论国产S79株腮腺炎疫苗免疫后抗体阳性率较低;为提高免疫成功率,建议尽量选用免疫效果较好的Jeryl-Lynn株和Jeryl-Lynn衍生株腮腺炎减毒活疫苗接种。     

国产水痘减毒活疫苗初次和加强免疫的免疫原性和安全性观察

目的观察国产水痘减毒活疫苗(Var V)初次免疫和加强免疫的免疫原性和安全性。方法采用单纯随机抽样方法选择16月龄儿童接种2剂次Var V(16月龄组),选择18月龄儿童接种1剂次Var V(18月龄组);分别采集受试者免疫前和每剂免疫后35-42d的血标本,采用膜免疫荧光抗体法(FAMA)检测水痘抗体;观察接种后30d内的不良反应。结果在16月龄组和18月龄组Var V初次免疫中,免疫前水痘抗体阳性率(SPR)分别为89.47%、87.96%(x~2=0.17,P=0.68),抗体几何平均滴度(GMT)分别为1∶5.80、1∶5.62(t=0.33,P=0.74);免疫后抗体阳转率(SCR)分别为49.56%、75.00%(x~2=19.44,P=0.00),GMT分别为1∶20.16、1∶35.23(t=5.94,P=0.00)。在16月龄组Var V加强免疫中,1剂次和2剂次免疫后SCR分别为49.52%和86.19%(x~2=64.72,P=0.00),GMT分别比免疫前增加2.53倍和7.01倍(F=433.97,P=0.00)。16月龄组第1剂次和第2剂次Var V、18月龄组1剂次Var V免疫后的局部红肿发生率分别为2.19%、0.95%、2.78%,发热发生率分别为0.88%、0.48%、0.93%,无其他不良反应报告。结论 Var V初次和加强免疫的免疫原性和安全性均良好。     

纯化乙型脑炎减毒活疫苗的免疫效果和不良反应观察

目的观察纯化乙型脑炎(乙脑)减毒活疫苗的免疫效果和不良反应。方法筛选405名8～20月龄无乙脑疫苗免疫史和419名18～36月龄并仅接种一次纯化乙型脑炎减毒活疫苗的二组健康婴幼儿为观察对象,接种纯化乙型脑炎减毒活疫苗后观察其接种不良反应,并在两组观察对象中抽取193名用细胞蚀斑减少中和试验检测免疫前和免疫后1个月血清乙脑中和抗体。结果纯化乙脑疫苗不良反应总发生率为5.22%;免疫成功率为78.9%;基础免疫后抗体阳性率为82.47%,GMT达1:23.1,1年后抗体阳性率为60.91%,GMT为1:10.9,加强免疫后1月抗体阳性率高达93.24%,GMT为1:28.6,基础、加强免疫前后抗体滴度分布、阳性率差异均有统计学意义。结论纯化乙型脑炎减毒活疫苗是一种安全、有效的乙脑疫苗,值得在控制乙脑工作中大力推广使用。     

育龄妇女麻疹抗体水平及免疫效果分析

目的:了解南昌市育龄妇女麻疹抗体水平,探讨育龄妇女接种麻疹疫苗的可行性,为完善麻疹免疫策略及控制麻疹疫情提供依据。方法:在南昌市的12个县(区)随机抽取健康育龄妇女,观察育龄妇女强化接种麻疹疫苗(MV)前后的麻疹IgG抗体,采用酶联免疫吸附试验(ELISA)检测麻疹IgG抗体。结果:南昌市育龄期妇女麻疹抗体血清几何平均滴度(GMT)为1∶482.64,抗体阳性率为80.79%,有随年龄增长呈下降的趋势;流动育龄期妇女麻疹抗体GMT和抗体阳性率均高于常住育龄期妇女,差异有统计学意义(P<0.05);有免疫史与无免疫史两组麻疹抗体GMT和抗体阳性率差异均有统计学意义(P=0.000),有免疫史者高于无免疫史者;育龄期妇女强化接种MV后麻疹抗体GMT为1∶1 616.47,抗体阳性率为98.52%,均显著高于接种前,差异有统计学意义(P=0.000)。结论:建议对育龄妇女婚前接种含麻疹成分的疫苗,提高育龄期妇女麻疹抗体水平,降低育龄妇女和MV初始免疫月龄前婴儿麻疹发病率。     

2014年扬州市健康人群流行性乙型脑炎抗体水平监测结果

目的了解扬州市健康人群流行性乙型脑炎(乙脑)抗体水平,为制定预防控制策略提供依据。方法 2014年6月乙脑流行季节前,分7个年龄组,每组随机抽取50名健康人,采用蚀斑减少中和试验法检测乙脑中和抗体。结果共检测356人,乙脑抗体阳性率为60.11%,GMT为1∶10.36。抗体阳性率、GMT<8月龄组最低,>20岁组最高,不同年龄组差异有统计学意义(χ2=91.18,P<0.05;F=23.82,P<0.05);有乙脑疫苗免疫史人群抗体阳性率高于无免疫史人群(χ2=27.68,P<0.05;F=16.19,P<0.05),且随着免疫剂次的增加而增加;不同性别抗体阳性率、GMT之间差异无统计学意义(χ2=0.76,P>0.05;F=1.25,P>0.05)。结论扬州市健康人群乙脑抗体水平主要受疫苗接种及由流行季节造成的隐性感染影响,2岁儿童乙脑抗体水平较低,建议增加6岁儿童复种1剂次乙脑疫苗的接种程序。     

深圳市某区2013年水痘疫苗接种儿童抗体水平横断面研究

目的观察儿童水痘疫苗1剂次接种后的免疫持久性及其可能的影响因素,为水痘疫苗加强免疫方案提供参考依据。方法采用横断面流行病学,对年龄2~7岁水痘疫苗初次免疫间隔1~5年的健康儿童566名采集静脉血,使用膜免疫荧光法(FAMA)测定水痘IgG水平。同时收集疫苗生产厂家及初免年龄等资料,用卡方检验分析率的差异,方差分析、t检验用于分析抗体滴度变化,多重线性回归用于分析抗体滴度变化的影响因素。结果水痘疫苗初免间隔1、3、5年后抗体阳性率(93.7%、87.6%、89.9%)差异无统计学意义(χ2=4.50,P=0.11),抗体滴度随时间衰减,不同间隔年限抗体水平差异有统计学意义(F=12.606,P0.001),间隔1年组的抗体水平(GMT:1:11.5)显著高于间隔3年(1:7.14,P0.001)、5年组(1:8.36,P=0.006)。间隔3年、5年组间抗体水平差异无统计学意义(P=0.387)。水痘疫苗初免年龄各间隔年限组间差异有统计学意义(χ2=276.069,P0.001),间隔1年组初免年龄最小,间隔5年组最大。国产疫苗和进口疫苗接种者的抗体阳性率相当,分别为91.%和89.5%,差异无统计学意义(χ2=0.322,P=0.570)。初免年龄、性别、疫苗种类对抗体滴度的影响差异均无统计学意义(P0.05)。结论国产疫苗和进口疫苗接种后免疫持久性效果相当,虽然初免5年后,抗体阳性率仍能维持较高水平,但抗体滴度随时间延长有所衰减,接种3~5年后抗体维持较低水平,建议在初次免疫后3年考虑加强免疫。     

2789例10岁以上儿童重组乙型肝炎疫苗加强免疫效果评价

目的 比较不同重组乙型肝炎(乙肝)疫苗加强免疫效果.方法 选择1周岁内完成血源乙肝疫苗基础免疫的10岁以上儿童2789例,分别接种4种国内常用的不同重组乙肝疫苗,分为A、B、C、D4组,采集血清,使用化学发光法检测HBsAg、抗-HBs、抗-HBc,仅抗-HBs阳性者接种1剂次、抗-HBs阴性者接种3剂次相应疫苗,免疫1个月后采血检测抗-HBs.结果 加强免疫前、免疫1剂次及3剂次后A、B、C、D 4组抗-HBs阳性率分别为36.43%、37.59%、42.91%、46.46%;89.20%、91.52%、90.96%、85.45%;99.12%、99.47%、98.87%、98.85%;加强免疫前、免疫1剂次及3剂次后两两之间抗-HBs阳性率差异均有统计学意义(P值均＜0.05).抗-HBs阴性者加强免疫1剂次、3剂次后,抗-HBs阳转率分别为83.01%、86.41%、84.16%、72.82%;98.62%、99.16%、98.03%、97.84%;与抗-HBs阳性者加强免疫1剂次相比,4组抗-HBs阳转率差异均有统计学意义(P＜0.05).抗-HBs阳性者加强免疫1剂次后几何平均滴度(GMT)分别为2853.21、6254.23、3581.40、3021.32 mIU/ml.抗-HBs阴性者加强免疫1剂次、3剂次后4组GMT分别为273.08、648.52、387.87、245.36 mIU/ml;632.30、2341.14、563.97、394.08 mIU/ml.结论 采用上述4种重组乙肝疫苗对抗-HBs阳性的10岁以上儿童加强免疫1剂次、对抗-HBs阴性的10岁以上儿童加强免疫3剂次,免疫效果良好.

Abstract：

Objective To study the efficiency of booster immunization with different recombinant hepatitis B vaccines.Methods 2789 children aged over 10 years who had completed the basic immunization of hepatitis B vaccine under 1 year old were selected.All the sampled children were classified into four groups (A,B,C and D) and immunized with different hepatitis B vaccines produced by different campanies respectively.Before booster immunization,their blood plasma specimens were detected for hepatitis B virus (HBV) surface antigen (HBsAg),antibodies to HBV surface antigen (anti-HBs) and antibodies to HBV core antigen (anti-HBc) by chemiluminescence.In each group,the anti-HBs positive children were immunized with one dosage and anti-HBs negative children were immunized three dosages of the same vaccine.Their blood specimens were collected again after 1 month,and detected for anti-HBs.Results The anti-HBs positive rates of A,B,C and D group were 36.43%,37.59%,42.91% and 46.46% respectively before immunization while 89.20%,91.52%,90.96% and 85.45% respectively after immunization with one dosage,99.12%,99.47%,98.87% and 98.85% respectively after immunization with three dosages.The differences of anti-HBs positive rates in the four respective groups showed statistical significances between any two rates of pre-immunization,post-immunization with one dosage and post- immunization with three dosages (all P＜0.05).The anti-HBs positive conversion rates of four groups were 83.01%,86.41%,84.16% and 72.82% respectively after immunization with one dosage.The anti-HBs positive conversion rate of four groups were 98.62%,99.16%,98.03% and 97.84% respectively after immunization with three dosages and the difference of positive conversion rates in each group showed statistical significances between booster immunization with one dosage and booster immunization with three dosages.The average GMTs in anti-HBs positive children in the four groups were 2853.21,6254.23,3581.40 and 3021.32 mIU/ml respectively after immunization with one dosage.The average GMTs of anti-HBs negative children in the four groups were 273.08,648.52,387.87 and 245.36 mIU/ml respectively after immunization with one dosage,and were 632.30,2341.14,563.97 and 394.08 mIU/ml respectively after immunization with three dosages.Conclusion Our data showed that it would be suitable to anyone to use the four vaccines for anti-HBs positive children aged over 10 years with one dosage and for anti-HBs negative children aged over 10 years with three dosage booster immunization.     

新型冠状病毒灭活疫苗不同接种间隔的免疫原性和安全性研究

目的 比较公安人员按不同方案（0~14 d、0~21 d、0~28 d）接种新型冠状病毒（新冠病毒）灭活疫苗的免疫原性和安全性。方法 于2021年1-2月以山西省太原市405名公安人员为研究对象,通过随机分组将其分为3组,分别按照0~14 d、0~21 d和0~28 d方案接种2剂新冠病毒灭活疫苗,采用RT-PCR检测新冠病毒核酸,活病毒微量病变法检测新冠病毒中和抗体,分析3组的新冠病毒中和抗体GMT、血清阳转率和安全性。结果 0~14 d、0~21 d和0~28 d方案组新冠病毒中和抗体血清学阳转率均为100%,其中0~21 d组[166.70（95%CI：148.30~185.10）]和0~28 d组[179.50（95%CI：156.50~202.60）]新冠病毒中和抗体水平接近（P>0.05）,均明显高于0~14 d组[86.08（95%CI：72.36~99.80）]（P<0.001）。3个方案组不良反应发生率分别为1.48%（2/135）、0.74%（1/136）和1.49%（2/134）（P=0.750）,均为轻度不良反应。结论 公安人员按不同方案（0~14 d、0~21 d、0~28 d）接种新冠病毒灭活疫苗后均表现出较好的血清阳转率和安全性,0~21 d和0~28 d接种方案组新冠病毒中和抗体GMT高于0~14 d方案组。     

流行性乙型脑炎灭活疫苗与减毒活疫苗相结合的免疫策略研究

目的　为合理利用流行性乙型脑炎 (乙脑 )灭活疫苗和减毒活疫苗各自的优点 ,降低预防接种反应的发生率 ,提高免疫学效果 ,开展了乙脑灭活疫苗与减毒活疫苗相结合的免疫策略研究。方法　观察比较两种疫苗单一使用与联合使用的免疫学效果及安全性。结果　联合使用组在疫苗接种后 2 4h的全身中强以上发热反应发生率为 0 .73 % ,局部红晕反应为 1 .46 % ,而单一使用灭活疫苗组的发热反应发生率为 2 .8%。不同观察组疫苗接种后中和抗体几何平均滴度由免疫前的 1∶1 .0 5～1∶3 .35上升至 1∶47.34～ 1∶1 0 1 .30 ,联合使用组的中和抗体阳转率为 97.67% ,明显高于单一使用灭活疫苗组 86 .2 7%的阳转率 (χ2 =3 .89,P <0 .0 5) ,但与单一使用减毒活疫苗组 93 .75 %的阳转率差异无显著性 (χ2 =0 .74,P >0 .0 5)。结论　研究表明对婴幼儿使用乙脑灭活疫苗基础免疫、减毒活疫苗加强免疫有很好的免疫学效果及安全性 ,也是切实可行和比较理想的免疫策略     

肠道病毒71型灭活疫苗(Vero细胞)分别与乙肝、乙脑疫苗联合接种的免疫原性研究

目的 评价、探索肠道病毒71型(enterovirus 71,EV71)灭活疫苗与免疫规划疫苗中的重组乙型肝炎疫苗(hepatitis B vaccine,HepB)、乙型脑炎减毒活疫苗(live-attenuated Japanese encephalitis vaccine,LJEV)联合接种的效果及可行性,为EV...     

新生儿5微克重组乙型肝炎疫苗（酿酒酵母）无应答者不同剂次和剂量再免疫血清学效果研究

目的评价新生儿接种5微克（μg）重组乙型肝炎（乙肝）疫苗（酿酒酵母）[Hepatitis B Vaccine（HepB）Made by Recombinant Deoxyribonucleic Acid Techniques in Saccharomyces Cerevisiae Yeast,HepB-SCY]后无应答者,使用不同剂次、剂量HepB再免疫后的血清学效果。方法抽取上海、山东、江苏、广西等省（自治区、直辖市）完成5μg HepBSCY全程免疫后的7~12月龄婴儿8945人,将其中的无应答者随机分为2组,分别采用5μg HepB-SCY和10μg HepB（汉逊酵母）（Hansenula Polymorpha Yeast,HPY）,按0、1、6个月程序进行再免疫,于再免疫第1、3剂后各1个月采血检测抗乙肝病毒表面抗原抗体（Antibody to Hepatitis B Virus Surface Antigen Anti-HBs）。结果 5μg HepBSCY组再免疫第1、3剂后,Anti-HBs阳转率分别为78.95%（60/76）和91.67%（66/72）,差异有统计学意义（χ2=4.73,P=0.03）。10μg HepB-HPY组再免疫第1、3剂后,Anti-HBs阳转率分别为92.65%（63/68）和100.00%（64/64）,差异无统计学意义[费希尔（Fisher）精确检验法,P=0.06]。5μg HepB-SCY组再免疫第1、3剂后,Anti-HBs的几何平均浓度（Geometric Mean Concentration,GMC）分别为45.79毫国际单位/毫升（mIU/ml）和193.83mIU/ml,差异有统计学意义（t=3.55,P=0.001）。10μg HepB-HPY组再免疫第1、3剂后,GMC分别上升为107.71 mIU/ml和302.54mIU/ml,差异有统计学意义（t=3.52,P=0.001）。再免疫第1剂后,10μg HepB-HPY组Anti-HBs的GMC高于5μg HepB-SCY组,差异有统计学意义（t=-2.10,P=0.037）。结论对5μg HepB-SCY初次免疫后无应答婴儿使用5μg HepB-SCY再免疫3剂,或10μg HepB-HPY再免疫1剂,能获得较理想的免疫应答;再免疫3剂比1剂可获得更高的抗体水平。     

TBE booster immunization according to the rapid immunization schedule: are 3-year booster intervals really necessary?

In order to evaluate the need for further booster immunizations, 222 subjects aged 20-52 years, who had received the first booster dose with a new tick-borne encephalitis (TBE) vaccine in a preceding study, were invited for a serological follow-up. A total of 191 and 182 adult subjects were analyzed for the persistence of neutralizing TBE antibodies at 1 and 2 years following the first booster immunization, respectively. Both serological follow-ups revealed high levels of neutralizing TBE antibodies in more than 99% of subjects. Although an expected decline of the respective geometric mean titers (GMTs) was noted after booster immunization, the titers were still far above the values noted after primary immunization at the 2-year follow-up. The kinetic curve clearly indicates a longer persistence of neutralizing TBE antibodies than currently expected. To conclude, these results suggest that the administration of a further booster dose 3 years after the first one (according to current recommendations) does not seem to be necessary in this study population.     

TBE booster immunization according to the rapid immunization schedule: are 3-year booster intervals really necessary?

In order to evaluate the need for further booster immunizations, 222 subjects aged 20–52 years, who had received the first booster dose with a new tick-borne encephalitis (TBE) vaccine in a preceding study, were invited for a serological follow-up. A total of 191 and 182 adult subjects were analyzed for the persistence of neutralizing TBE antibodies at 1 and 2 years following the first booster immunization, respectively. Both serological follow-ups revealed high levels of neutralizing TBE antibodies in more than 99% of subjects. Although an expected decline of the respective geometric mean titers (GMTs) was noted after booster immunization, the titers were still far above the values noted after primary immunization at the 2-year follow-up. The kinetic curve clearly indicates a longer persistence of neutralizing TBE antibodies than currently expected. To conclude, these results suggest that the administration of a further booster dose 3 years after the first one (according to current recommendations) does not seem to be necessary in this study population.     

Immunogenicity of an adjuvanted SARS-CoV-2 trimeric S-protein subunit vaccine (SCB-2019) in SARS-CoV-2-naïve and exposed individuals in a phase 2/3, double-blind,randomized study

BackgroundWe evaluated immunogenicity of SCB-2019, a subunit vaccine candidate containing a pre-fusion trimeric form of the SARS-CoV-2 spike (S)-protein adjuvanted with CpG-1018/alum.MethodsThe phase 2/3, double-blind, randomized SPECTRA trial was conducted in five countries in participants aged ≥ 18 years, either SARS-CoV-2-naïve or previously exposed. Participants were randomly assigned to receive two doses of SCB-2019 or placebo administered intramuscularly 21 days apart. In the phase 2 part of the study, on days 1, 22, and 36, neutralizing antibodies were measured by pseudovirus and wild-type virus neutralization assays to SARS-CoV-2 prototype and variants, and ACE2-receptor-binding antibodies and SCB-2019–binding antibodies were measured by ELISA. Cell-mediated immunity was measured by intracellular cytokine staining via flow cytometry.Results1601 individuals were enrolled between 24 March and 13 September 2021 and received at least one vaccine dose. Immunogenicity analysis was conducted in a phase 2 subset of 691 participants, including 428 SARS-CoV-2-naïve (381 vaccine and 47 placebo recipients) and 263 SARS-CoV-2-exposed (235 vaccine and 28 placebo recipients). In SARS-CoV-2-naïve participants, GMTs of neutralizing antibodies against prototype virus increased 2 weeks post-second dose (day 36) compared to baseline (224 vs 12.7 IU/mL). Seroconversion rate was 82.5 %. In SARS-CoV-2-exposed participants, one SCB-2019 dose increased GMT of neutralizing antibodies by 48.3-fold (1276.1 IU/mL on day 22) compared to baseline. Seroconversion rate was 92.4 %. Increase was marginal post-second dose. SCB-2019 also showed cross-neutralization capability against nine variants, including Omicron, in SARS-CoV-2-exposed participants at day 36. SCB-2019 stimulated Th1-biased cell-mediated immunity to the S-protein in both naïve and exposed participants. The vaccine was well tolerated, no safety concerns were raised from the study.ConclusionsA single dose of SCB-2019 was immunogenic in SARS-CoV-2-exposed individuals, whereas two doses were required to induce immune response in SARS-CoV-2-naïve individuals. SCB-2019 elicited a cross-neutralizing response against emergent SARS-CoV-2 variants at antibody levels associated with clinical protection, underlining its potential as a booster.Clinicaltrials.gov: NCT04672395; EudraCT: 2020-004272-17.     

烟台市18岁及以上人群新冠疫苗加强免疫接种意愿调查

目的 调查烟台市18岁及以上人群新冠疫苗加强免疫的接种意愿，为相关卫生主管部门开展新冠肺炎加强免疫工作提供参考。方法 采用整群抽样方法，在烟台市14个区市中，每个区市随机抽取2个城市社区和2个行政村作为调查区域，对区域内18岁及以上全部人群进行问卷调查。结果 共有138 664名研究对象完成问卷调查，94.52%的研究对象表示愿意接种新冠疫苗加强剂次。不同年龄（χ2 = 616.448，P＜0.001）、职业（χ2 = 85.000，P＜0.001）、文化水平（χ2 = 659.261，P＜0.001）、居住地（χ2 = 84.803，P＜0.001）以及已是否接种新冠疫苗（χ2 = 2 429.739，P＜0.001）调查对象的接种加强剂次意愿差异有统计学意义，不同性别的接种加强剂次意愿差异无统计学意义（χ2 = 0.328，P = 0.567）。结论 烟台市居民对新冠疫苗加强免疫接种意愿较高，但部分居民对接种加强免疫的认识存在片面性，影响了接种加强免疫的积极性，建议加强新冠疫苗加强免疫相关知识的宣传教育。