b型流感嗜血杆菌结合疫苗中载体蛋白质的效力研究

考察b型流感嗜血杆菌(Hib)结合疫苗的载体蛋白质—破伤风类毒素(TT)的免疫原性,为百白破与Hib四联疫苗中TT的使用提供参考。方法:将小鼠随机分为四组,分别注射Hib结合疫苗、Hib与百白混合疫苗、Hib与百白破混合疫苗、破伤风类毒素,比较它们在NIH小鼠体内所诱导产生的特异性抗体水平,并对这四组疫苗进行破伤风效力保护试验。结果表明,破伤风类毒素组,Hib与百白破混合疫苗组刺激的TT抗体水平远大于Hib结合疫苗组和Hib与百白混合疫苗组。效力试验虽四组间没有差异,只说明一定的抗体量就可以对小鼠提供保护。认为Hib结合疫苗中的载体蛋白并不能替代百白破疫苗中的破伤风类毒素。     

国产b型流感嗜血杆菌结合疫苗免疫原性观察

目的:了解兰州生物制品研究所研制的b型流感嗜血杆菌结合疫苗的免疫原性。方法:采用单纯随机抽样方法对柳州市709名3～59月龄婴幼儿按照规定的免疫程序接种兰州所(或巴斯德)Hib疫苗,2年内在不同时段采集血清样本,采用ELISA方法检测Hib-PRP抗体滴度。结果:基础免疫后血清Hib-PRP抗体含量平均水平为18.043μg/ml,抗体阳转率为97.19%,1年后血清Hib-PRP抗体含量为7.575μg/ml,抗体阳转率为93.75%。加强免疫后血清Hib-PRP抗体含量为130.330μg/ml,抗体阳转率为100.00%,加强免疫1年后血清Hib-PRP抗体含量为51.723μg/ml,抗体阳转率为100.00%。基础免疫后接种巴斯德Hib疫苗组血清Hib抗体含量高于接种兰州所Hib疫苗组,抗体阳转率则没有差别;免后1年,接种兰州所Hib疫苗儿童体内Hib抗体含量平均水平高于接种法国巴斯德Hib疫苗儿童;其余各时段两组儿童血清Hib-PRP抗体含量及抗体阳转率均无差别。结论:兰州所Hib疫苗有较好的免疫原性和免疫持久性。     

破伤风类毒素-细菌多糖结合疫苗中载体蛋白识别的结构性标志物

正细菌性脑膜炎的全球负担主要是由于奈瑟脑膜炎球菌和肺炎链球菌的侵袭性感染造成的。发达国家在1987年引入b型流感嗜血杆菌(Hib)结合疫苗前,Hib是许多细菌性脑膜炎的病因。Hib结合疫苗降低了Hib发病率达80%或更多,这依赖于疫苗的普及程度。单价脑膜炎球菌C群(Men C)疫苗于1999—2000年上市,在英国降低了由Men C引起的侵袭性脑膜炎球菌病90%以上。现在有3个上市     

两种恒温状态下疫苗温度指示标签对Hib结合疫苗的有效性研究

目的研究25℃与37℃恒温状态下疫苗温度指示标签(vaccine vial monitor, VVM)失效时间与b型流感嗜血杆菌(Haemophilus influenzae type b, Hib)结合疫苗有效性指标之间的关系,判断VVM对疫苗温度暴露情况的指示作用是否可靠。方法将检定合格的3批贴有VVM标签的Hib结合疫苗分别放置于25℃与37℃温度中,25℃放置的样品于0、10、20、30、40、50、60 d取样,37℃放置的样品于3、7、9 d取样,检测VVM反应区与参照区吸光度差值和Hib结合疫苗各有效性质量指标之间的关系。当测量VVM上至少2个点的A_(R-I)≤0.00时,肉眼观察反应区颜色与参照区颜色相同或更深,提示VVM失效。绘制VVM吸光度差值结果与疫苗有效性变化统计表和曲线图,研究VVM与疫苗失效时间的先后顺序,了解VVM是否存在先于疫苗失效的情况。结果 25℃时,VVM开始失效的时间范围为45～50 d;37℃下,VVM开始失效的时间范围为6～7 d。疫苗在25℃放置60 d和37℃放置7 d,各有效性指标均符合标准规定。观察期内未发现疫苗失效情况,疫苗稳定性较好。结论 2种温度下VVM均于疫苗失效前到达终点。证明VVM应用于Hib结合疫苗的匹配性良好,可反映该疫苗的热暴露情况,为疫苗接种前的有效性确认提供可靠帮助。     

四价脑膜炎球菌结合疫苗或第四剂流感嗜血杆菌-脑膜炎C/Y结合疫苗对婴儿期曾接受HibMenCY-TT三剂免疫的儿童具有免疫原性

正背景:在幼儿接种流感嗜血杆菌-脑膜炎C/Y结合疫苗(HibMenCY-TT)疫苗的第二年进行单剂四价脑膜炎球菌结合疫苗(Men ACWY-TT)或第四剂Hib Men CY-TT的安全性和免疫原性的评价。方法:健康婴儿被随机(5∶1)分组,在2、4和6个月龄接种Hib Men CY-TT和白喉-破伤风-无细胞百日咳-乙肝-灭活脊髓灰质炎病毒(DTa PHBV-IPV)疫苗;或Hib-TT和DTaP-HBV-IPV疫苗(对照组)。     

2011—2016年河南省b型流感嗜血杆菌结合疫苗预防接种不良反应监测分析

目的分析2011—2016年河南省b型流感嗜血杆菌结合疫苗(简称Hib疫苗)预防接种不良反应的发生特征,评价Hib疫苗预防接种的安全性。方法通过中国免疫规划信息管理系统,收集2011—2016年河南省报告的Hib疫苗不良反应个案数据和Hib疫苗接种数据,采用描述流行病学方法对其进行分析。结果 2011—2016河南省共报告Hib疫苗接种不良反应960例,年平均报告发生率为10.55/10万剂次;以一般反应为主,占93.23%;4—8月为高峰;主要集中在郑州市、洛阳市、濮阳市和周口市;男性多于女性;<1岁儿童为主要报告人群;不良反应主要发生在首剂次接种后及接种后2 d内。一般反应的主要症状为发热、红肿、硬结,异常反应主要为过敏反应性疾病,治愈或好转达99.79%。结论 Hib疫苗不良反应报告发生率较低,具有良好的安全性。     

重组(CHO细胞)乙型肝炎疫苗细菌内毒素含量检测法的建立

采用鲎试剂法检测重组 (CHO细胞 )乙型肝炎疫苗中的细菌内毒素含量 ,研究了甲醛、硫柳汞、氢氧化铝等疫苗成分对鲎试剂试验的影响。结果表明 ,疫苗中各成分对检测未见影响 ,所以检测本疫苗中内毒素含量时 ,采用鲎试剂法是可行的。同时 ,用此试验方法对本室所生产的重组 (CHO细胞 )乙型肝炎疫苗进行了检测 ,疫苗中内毒素含量全部合格     

b型流感嗜血杆菌疫苗的研究进展及应用策略

b型流感嗜血杆菌(Hib)是儿童感染性疾病的主要原因之一,常引起严重感染,自Hib疫苗问世以来,已有九十多个国家的儿童接种了该疫苗,在常规接种疫苗的国家Hib疾病的发病率迅速下降,Hib疾病成为可用疫苗预防的疾病。本文对Hib疫苗的发展及免疫策略作一综述。     

b型流感嗜血杆菌培养及细菌溶解产物制备工艺研究

目的研究b型流感嗜血杆菌(Haemophilus influenza type b,Hib)培养条件及细菌溶解产物制备工艺。方法比较Hib在传统培养基和改良培养基的生长情况,优化改良培养基在生物反应器中对Hib培养条件(p H值、温度、溶解氧等),研究最佳菌体细胞破碎方法及细菌溶解产物纯化制备工艺。结果改良培养基可代替传统培养基用于Hib的生产培养,且Hib在p H7.4、温度为36℃、溶解氧为25%的改良培养基中,生长迅速,菌体产量最高。高压匀浆破碎法的破碎效果明显优于超声波破碎法,破碎效果达到98%以上,纯化后的细菌溶解产物的多糖含量、总氮含量、蛋白质含量、核酸含量及细菌内毒素含量均符合《中华人民共和国药典》(三部)2010版中b型流感嗜血杆菌结合疫苗的质量标准。结论初步建立了b型流感嗜血杆菌培养及细菌溶解产物制备工艺。     

乙型脑炎灭活疫苗细菌内毒素检查方法的研究

将细菌内毒素检查法(凝胶法)扩大应用于乙脑灭活疫苗的质量控制及其内毒素的检测.按<中国药典>及<中国生物制品规程方法>方法,复核鲎试剂灵敏度、确定疫苗的L值、计算MVD、进行干扰试验及内毒素的检测.疫苗L值确定为300 EU/mL,MVD为1 200倍.用灵敏度0.25 EU/mL的鲎试剂,疫苗的最大非干扰浓度为将其稀释30倍,将此疫苗稀释120倍进行干扰试验,对内毒素的检测无干扰作用.以此法对15批疫苗进行内毒素检查均呈阴性反应.结果显示,此法用于乙脑灭活疫苗质量控制及其内毒素检查是可行的.     

DTaP-Hib联合疫苗中Hib-TT免疫原性研究

考查DTaP-Hib联合疫苗中Hib-TT的免疫原性,对其剂量、免疫持久性和抗原相容性进行分析。将不同剂量的Hib-TT、DTaP-Hib联合疫苗分别免疫小鼠,设单价的Hib-TT结合疫苗为对照,末次免疫后1、2、4、6、8、10w分别采集血清测定血清中Hib多糖抗体滴度。结果显示,不同剂量的Hib-TT和DTaP疫苗联合后均具有较好的免疫原性,血清中Hib多糖抗体阳转率达100%,并具有剂量效应和较好的免疫持久性。2.5μg剂量Hib-TT的DTaP-Hib联合疫苗免疫小鼠后1~2w诱导产生的Hib多糖抗体水平显著性地低于单价Hib-TT(P<0.05),4~10w,二者的Hib多糖抗体水平无显著性差异(P>0.05)。5μg剂量Hib-TT的DTaP-Hib联合疫苗在免疫小鼠后1w诱导产生的Hib多糖抗体水平与单价2.5μg剂量Hib-TT无显著性差异(P>0.05),免后2~10w则显著性地高于单价2.5μg剂量Hib-TT(P<0.001)。Hib-TT和DTaP疫苗联合后,仍然具有较好的免疫原性、剂量效应和免疫持久性;其抗原性干扰只是暂时的。     

Evaluation of a guinea pig model to assess interference in the immunogenicity of different components of a combination vaccine comprising diphtheria, tetanus and acellular pertussis (DTaP) vaccine and haemophilus influenzae type b capsular polysaccharide conjugate vaccine.

A guinea pig model to assess the immunogenicity of a combination vaccine containing diphtheria, tetanus and acellular pertussis (DTaP) vaccine and Haemophilus influenzae type b (Hib) capsular polysaccharide conjugated to tetanus toxoid (HibT) was evaluated comparatively with the mouse immunogenicity test to study the effect of combining these antigens on the immunogenicity of various components. The immunogenicity test in mice was performed by subcutaneous injection of groups of 10 animals twice at an interval of four weeks with 1/10 of a single human dose of various formulations of combination vaccines, DTaP or HibT vaccine. The animals were bled at 4 and 6 weeks and IgG or total antibodies to various components were determined by ELISA or RIA. The guinea pig immunogenicity model included groups of animals injected subcutaneously twice at an interval of six weeks with 1.5 times the single human dose of various formulations. The animals were bled at 4, 6 and 8 weeks and serum samples were tested for antibodies to various components by ELISA, RIA and/or neutralization tests. Additionally, potency of tetanus and diphtheria components was assessed as per the US Food and Drug Administration's regulations. Aluminium phosphate (AIPO(4)) adsorbed HibT vaccine or HibT as a combination with AIPO(4)adsorbed DTaP vaccine showed significant increases in IgG antibodies to tetanus toxin in mice as well increased tetanus antitoxin levels in guinea pigs as compared to soluble HibT vaccine. In general, combining DTaP and HibT vaccines did not affect the antibody levels to tetanus and diphtheria toxoids whereas DTaP-HibT combination vaccine elicited significantly lower IgG antibodies to pertussis toxin and filamentous haemagglutinin than DTaP vaccine alone, particularly after first injection. Mice showed similar Hib antibody responses for the combination and HibT alone whereas guinea pigs consistently showed lower anamnestic responses to Hib for combination formulations than for HibT alone. Reducing the amount of HibT and/or tetanus toxoid in the combination formulations reduced this suppression of Hib antibody response in guinea pigs. Suppression of Hib antibody response in combination vaccines has also been reported from recent clinical trials. Based on the results from this study, it appears that the guinea pig model may be able to predict the human response to various components of combination vaccines.     

The Impact of Residency and Urbanicity on Haemophilus influenzae Type b and Pneumococcal Immunization in Shanghai Children: A Retrospective Cohort Study

Background

Haemophilus influenzae type b (Hib) vaccine and pneumococcal conjugate vaccine (PCV) are relatively expensive, newly introduced vaccines in China. This study evaluates the impact of residency and urbanicity on Hib vaccine and PCV coverage for children aged 2 to 7 years living in Shanghai, China, in August 2012.

Methods

In this exploratory cohort study, a sample of children aged 2 to 7 years, all of whom were eligible to have received the complete series of Hib vaccine and PCV, was obtained from the Shanghai Immunization Program Information System. Three measures of vaccination coverage for Hib vaccine and PCV were examined: dose 1 coverage, series completion, and timeliness of dose 1 vaccination. Multivariable binomial regression was used to estimate the difference in vaccination coverage between locals and the floating population.

Results

Dose 1 coverage was 50.9% for Hib vaccine and 11.4% for PCV for the 28,141 abstracted pediatric records. For both vaccines, dose 1 coverage was higher in locals than in the floating population. The disparity in coverage between locals and the floating population was greater in suburban areas than urban areas. Of all children who received dose 1, 79.7% completed the Hib vaccine series, and 91.3% completed the PCV series. Timely dose 1 coverage was 8.2% for Hib vaccine and 0.5% for PCV.

Conclusion

Low vaccination coverage and extremely low levels of timely dose 1 vaccination indicate that current vaccination efforts are inadequate to reduce the burden of Hib and pneumococcal disease among Chinese children, especially infants. Government funding of the Hib vaccine and PCV through the Expanded Program on Immunization would increase uptake and could also ensure that improvement in the timeliness of administration and series completion is targeted for all demographic groups.     

Mutual interactions between DTaP-IPV and Haemophilus influenzae type b (Hib)-conjugated vaccines in laboratory animal models.

Potency and/or immunogenicity of three different Haemophilus influenzae type b-conjugated vaccines (Hib) and a DTaP-IPV vaccine alone, and their mutual interactions in DTaP-IPV-Hib combination was tested. In a mouse model, only combination of Act-Hib, in which tetanus toxoid (TT) was as active as non-conjugated TT, significantly increased the immunogenicity and potency of TT component of DTaP-IPV vaccine. Also, only combination of Hib-TITER, in which CRM197 was used as the carrier with DTaP-IPV, increased the potency of diphtheria toxoid (DT) component of DTaP-IPV vaccine significantly. It shows that the additive effect of tested Hib vaccines on immunogenicity and/or potency of TT and DT was mostly due to the existence of TT and CRM197, respectively, as the carrier in the mentioned Hib vaccines. No difference was shown in inoculation of DTaP-IPV and Hib conjugated vaccines in the same syringe or at separate sites. DTaP-IPV had dual effects on anti-Hib capsular polysaccharide (HibCP) responses to Hib vaccines in the mouse model. This duality was probably related to the carrier B-cell epitopes activity of Hib conjugated vaccines. The immunogenicity of TT component of Act-Hib and Amvax Hib-TT in the guinea pig model was shown and combination of mentioned Hib vaccines with DTaP-IPV, remarkably increased anti-TT antibody responses to the TT component of DTaP-IPV vaccine. These confirmed our results in the mouse model. Using two different protocols to evaluate the guinea pig model for induction of anti-HibCP immunity showed that a "long interval" protocol does not have any advantage over the "short interval" protocol. Also, combination of DTaP-IPV with Hib vaccines did not have any noticeable effect on anti-HibCP antibodies in the guinea pig model. Taken together, our observations in laboratory animal models may facilitate a better understanding of the mutual interactions between the different antigen components of a combined vaccine such as DTaP-IPV-Hib vaccine.     

Process development of a New Haemophilus influenzae type b conjugate vaccine and the use of mathematical modeling to identify process optimization possibilities

Vaccination is one of the most successful public health interventions being a cost‐effective tool in preventing deaths among young children. The earliest vaccines were developed following empirical methods, creating vaccines by trial and error. New process development tools, for example mathematical modeling, as well as new regulatory initiatives requiring better understanding of both the product and the process are being applied to well‐characterized biopharmaceuticals (for example recombinant proteins). The vaccine industry is still running behind in comparison to these industries. A production process for a new Haemophilus influenzae type b (Hib) conjugate vaccine, including related quality control (QC) tests, was developed and transferred to a number of emerging vaccine manufacturers. This contributed to a sustainable global supply of affordable Hib conjugate vaccines, as illustrated by the market launch of the first Hib vaccine based on this technology in 2007 and concomitant price reduction of Hib vaccines. This paper describes the development approach followed for this Hib conjugate vaccine as well as the mathematical modeling tool applied recently in order to indicate options for further improvements of the initial Hib process. The strategy followed during the process development of this Hib conjugate vaccine was a targeted and integrated approach based on prior knowledge and experience with similar products using multi‐disciplinary expertise. Mathematical modeling was used to develop a predictive model for the initial Hib process (the ‘baseline’ model) as well as an ‘optimized’ model, by proposing a number of process changes which could lead to further reduction in price. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:568–580, 2016     

Comparative economic evaluation of Haemophilus influenzae type b vaccination in Belarus and Uzbekistan

Background

Hib vaccine has gradually been introduced into more and more countries during the past two decades, partly due to GAVI Alliance support to low-income countries. However, since Hib disease burden is difficult to establish in settings with limited diagnostic capacities and since the vaccine continues to be relatively expensive, some Governments remain doubtful about its value leading to concerns about financial sustainability. Similarly, several middle-income countries have not introduced the vaccine. The aim of this study is to estimate and compare the cost-effectiveness of Hib vaccination in a country relying on self-financing (Belarus) and a country eligible for GAVI Alliance support (Uzbekistan).

Methods and Findings

A decision analytic model was used to estimate morbidity and mortality from Hib meningitis, Hib pneumonia and other types of Hib disease with and without the vaccine. Treatment costs were attached to each disease event. Data on disease incidence, case fatality ratios and costs were primarily determined from national sources. For the Belarus 2009 birth cohort, Hib vaccine is estimated to prevent 467 invasive disease cases, 4 cases of meningitis sequelae, and 3 deaths, while in Uzbekistan 3,069 invasive cases, 34 sequelae cases and 341 deaths are prevented. Estimated costs per discounted DALY averted are US$ 9,323 in Belarus and US$ 267 in Uzbekistan.

Conclusion

The primary reason why the cost-effectiveness values are more favourable in Uzbekistan than in Belarus is that relatively more deaths are averted in Uzbekistan due to higher baseline mortality burden. Two other explanations are that the vaccine price is lower in Uzbekistan and that Uzbekistan uses a three dose schedule compared to four doses in Belarus. However, when seen in the context of the relative ability to pay for public health, the vaccine can be considered cost-effective in both countries.     

Presence of multiple copies of capsulation loci in invasive Haemophilus influenzae type b (Hib) strains in Japan before introduction of the Hib conjugate vaccine

Despite the effectiveness of the Hib vaccine, multiple amplification of the capb locus contributes to vaccine failure. However, there has been no report on the effect of Hib locus amplification in Japan. We examined 24 Hib strains from Japanese children with invasive diseases due to Hib. Although all strains showed the same capb sequence, Southern blot analysis showed that four strains (16.7%) harbored multiple copies (more than two) of the capb locus. Careful analysis of the locus in circulating Hib strains is necessary now that the Hib vaccine has been introduced into Japan.     

Difficulties in Establishing a Serological Correlate of Protection After Immunization with Haemophilus Influenzae Conjugate Vaccines

Abstract. in several studies the protective concentration of anti-Haemophilus infiuenzae type b (Hib) capsular polysaccharide (PS) antibodies has been concluded to be around 0·04 to 0·20 μg/ml. After the Finnish Hib polysaccharide vaccine trial it was estimated that 1 μg/ml has to be achieved to predict long term protection after vaccination. These estimates of protective anti-Hib PS antibody concentrations were based on the assumption that protection from invasive Hib disease is mediated by antibodies and the role of cell-mediated immunity is negligible. This assumption was justified since the Hib PS is a T cell-independent antigen. The matter becomes quite different when the character of the PS vaccine is altered by conjugating it to a protein carrier, so that it acquires the ability to stimulate T cells, and the immunological memory plays a role in the protection. The immunized infants are thought to be able to respond with a rapid and high antibody response after exposure to the organism. After immunization with conjugate vaccines, protection can be seen at a lower serum antibody concentration than after polysaccharide vaccine. In addition, higher avidity of anti-Hib PS antibodies is associated with the response to conjugate than PS vaccine, and there are differences between the conjugates. This might have an influence on the functional activity of the antibodies. Hib conjugate vaccines are also able to reduce the carriage rate of Hib. This should be kept in mind when estimating what is needed from protective immune response after immunization with Hib conjugate vaccines.     

Evaluation of Haemophilus influenzae type b carrier status among children 10 years after the introduction of Hib vaccine in Brazil

The aim of the present study was to assess the prevalence of Haemophilus influenzae type b (Hib) nasopharyngeal (NP) colonisation among healthy children where Hib vaccination using a 3p+0 dosing schedule has been routinely administered for 10 years with sustained coverage (> 90%). NP swabs were collected from 2,558 children who had received the Hib vaccine, of whom 1,379 were 12-< 24 months (m) old and 1,179 were 48-< 60 m old. Hi strains were identified by molecular methods. Hi carriage prevalence was 45.1% (1,153/2,558) and the prevalence in the 12-< 24 m and 48-< 60 m age groups were 37.5% (517/1,379) and 53.9% (636/1,179), respectively. Hib was identified in 0.6% (16/2,558) of all children in the study, being 0.8% (11/1,379) and 0.4% (5/1,179) among the 12-< 24 m and 48-< 60 m age groups, respectively. The nonencapsulate Hi colonisation was 43% (n = 1,099) and was significantly more frequent at 48-< 60 m of age (51.6%, n = 608) compared with that at 12-< 24 m of age (35.6%, n = 491). The overall resistance rates to ampicillin and chloramphenicol were 16.5% and 3.7%, respectively; the co-resistance was detected in 2.6%. Our findings showed that the Hib carrier rate in healthy children under five years was very low after 10 years of the introduction of the Hib vaccine.