Clinical trial of the Oka strain of live attenuated varicella vaccine on healthy children

Clinical and serological follow-up studies were made on 257 healthy children who had received live varicella vaccine (strain Oka) in Showa Hospital. Good antibody responses were shown with a seroconversion rate of 98.4% (253/257) by the immune adherence hemagglutination test. Mild adverse reactions were observed in 11 of the vaccinated children. During observation periods of 6 months to 4 years, 6 of the 253 children who were successfully vaccinated contracted mild varicella, while all 4 vaccinees who showed no primary immune response contracted mild to moderate clinical varicella. It is concluded that this vaccine is highly immunogenic and causes few clinical reactions in normal children.     

Clinical application of a live varicella vaccine (Oka strain) in a hospital

A total of 239 children, including 22 high-risk children and 55 non-high risk diseased children have been immunized with a live varicella vaccine (Oka strain) since June, 1978. No clinical reaction attributable to the vaccine has been observed. Of these children, 87 received emergency vaccination. Of 47 children receiving emergency vaccination because they had been in contact with varicella patients either in hospital, school or a playground, only 5 developed varicella and their symptoms were mild. Of 40 children receiving emergency vaccination because of exposure to varicella in their home, 10 developed mild varicella and 30 were protected. Clinical symptoms of varicella when seen seemed to be due to incomplete protection because the vaccine was given too late rather than to clinical reactions to the vaccine. During follow-up period of 6 to 66 months after vaccination, 8 children showed very mild rashes without fever as the result of exogenous varicella infection.     

A five-year immunological follow-up study of the institutionalized handicapped children vaccinated with live varicella vaccine or infected with natural varicella

Twenty-two institutionalized handicapped children who were susceptible to varicella were vaccinated with live varicella vaccine of the Oka strain and their immune status was followed for 5 years under conditions without exposure to natural varicella. Simultaneously, 7 children infected with natural varicella were followed. Of the 22 vaccinees, 16 showed sero-positive conversion by the fluorescent antibody to membrane antigen (FAMA) test, the other 6 remaining seronegative during 5 years of observation period. All the 16 cases showing seroconversion had detectable antibody for 5 years after vaccination, and 14 of them gave a positive reaction in the varicella skin test. All the 7 cases after natural varicella gave positive reactions in both the FAMA and skin test. These results suggest that immunity conferred by the vaccination would persist long even in the absence of exposure to natural varicella, though further follow-up studies are needed.     

Immunization of acute leukemic children with a live varicella vaccine (Oka strain)

A total of 52 acute leukemic children have been safely and effectively vaccinated with live varicella (Oka strain) vaccine given under close clinical and immunological observation. The incidence of zoster in the vaccinated children group was slightly less than that in the group that had experienced natural varicella.     

Spread of varicella in hospitalized children having no direct contact with an indicator zoster case and its prevention by a live vaccine

Varicella spread from a child with zoster to a total of 3 susceptible infants in another room in a children's ward, although they had been strictly isolated. To prevent spread of the disease, the staffs and patients were doing their own washing and no source of natural infection could be found. The cases indicate that it is difficult to predict nosocomial varicella infection or to prevent spread of the disease simply by isolation in a children's ward. A total of 11 other children without history of varicella in the ward were given live varicella vaccine before or immediately after this event. None of these children developed symptoms of varicella and all the susceptible children who were vaccinated showed an antibody response.     

Development of a live attenuated varicella vaccine.

The Oka strain of varicella virus, isolated in our labolatory, was serially cultivated in guinea-pig embryo cultures (GPEC), and a considerable amount of cell-free virus was obtained from infected cell. GPEC passage virus at the 6th passage level was used in a small scale field trial. Susceptible children of 1 to 10 years old were injected subcutaneously with 100 to 1,000 PFU of virus. No clinical reactions due to the vaccination were observed in any children, and a high rate of antibody response was obtained with viral doses of more than 200 PFU. Attenuated virus obtained by passage in GPEC was propagated in human diploid (WI-38) cells, and it was also effective in inducing an immune response without clinical reactions. The results show that the Oka strain of varicella virus passaged in GPEC and human diploid (WI-38) cells may be used safely and effectively as a live attenuated vaccine.     

国产冻干水痘减毒活疫苗免疫原性研究与应用

对１２９名４岁儿童采用国产、进口水痘减毒活疫苗进行免疫,对疫苗的安全性和免疫原性进行研究,用ＥＬＩＳＡ进行免前、免后水痘抗体测定。结果表明国产水痘疫苗接种后无明显副反应,国产、进口疫苗血清的阳转率相似,达８５％以上,证明国产ＯＫａ株水痘减毒活疫苗具有良好的安全性和免疫性,可以推广使用。     

Immune response induced by live attenuated varicella vaccine and short term follow-up on immunity of the vaccinated children

Live attenuated varicella vaccine (Oka strain, 500 to 750 PFU) was inoculated into 234 children with various underlying diseases. Varicella-zoster virus (VZV) specific immune adherence hemagglutination antibody developed in 95% of initially seronegative subjects. VZV specific cellular immune responses were detected in 91% of subjects within 6 weeks after vaccination. A preliminary survey of 46 vaccinated normal-risk subjects during the first and the third year revealed excellent protection with the exception of one case who had not shown any antibody response at the fourth week.     

建立膜抗原荧光抗体试验评价北京株冻干水痘疫苗免疫效果

为了建立用于水痘疫苗接种后血清中特异性抗体检测的膜抗原荧光抗体(FAMA)法,并对接种水痘疫苗后儿童血清中水痘特异性抗体进行检测,评价北京株水痘疫苗的免疫效果。以水痘带状疱疹病毒(VZV)感染细胞作为抗原制备成固定抗原玻片,以异硫氰酸荧光素(FITC)标记的羊抗人IgG作为二抗建立FAMA法,并对该法的敏感性、特异性进行验证。运用此法对不同剂量北京株水痘疫苗接种后儿童血清中特异性抗体进行检测,分析儿童血清中水痘特异性抗体水平以及免后抗体阳转率,并与Oka株水痘疫苗进行比较。结果显示,FAMA法敏感性可达0.0196IU/ml,特异性好。应用此法检测300名观察者免前免后双份血清样本中抗VZVIgG,易感者中北京株水痘疫苗原苗(39810PFU/0.5ml)、2000PFU/0.5ml、500PFU/0.5ml接种组儿童血清免后抗体阳转率分别为100%、98.77%、85.42%,抗体几何平均滴度(GMT)分别为36.4、34.3、18.6,原苗与2000PFU间的抗体阳转率和GMT均无显著性差异(P>0.05),但原苗与500PFU、2000PFU与500PFU间的抗体阳转率和GMT均有显著性差异(P<0.05)。对照国产、进口Oka株水痘疫苗接种后抗体阳转率分别为95.35%、96.97%,抗体GMT分别为13.3、16.0,不同剂量北京株疫苗抗体阳转率与国产、进口Oka株疫苗相比,差别无显著性(P>0.05),但北京株疫苗原?     

Live varicella vaccine: prevention of nosocomial infection and protection of high risk infants from varicella infection

For prevention of nosocomial infection, 25 infants including high risk patients received an emergency injection of live varicella vaccine. Three patients developed a rash within 5 days after vaccination, but their symptoms were mild. The other 22 showed no clinical symptoms and gave an immune response. Twenty-two patients receiving immunosuppressive therapy were vaccinated and 20 of them showed a positive response in the varicella skin test. Of 14 vaccinated patients with malignancies, 2 giving a positive skin test, later showed clinical varicella, but their symptoms were not severe. One case with ALL was immunized safely under very poor conditions during the first induction therapy. No complications were observed in any patients.     

Evaluation of varicella vaccine in childhood leukemia. Observation over 6 years

Since 1977, we have used a live attenuated varicella vaccine to immunize 10 children with acute leukemia. 8 patients had no adverse clinical reaction but 2 patients developed mild fever and papulovesicular rash after vaccination. All 9 tested children became seropositive after the vaccination. Also in all 3 children who were observed for more than 4 years, persistence of neutralizing antibody was detected. Most of the recipients were prevented from developing symptoms of varicella in spite of contact exposure. Two patients developed varicella when they were in severe immunosuppressive states but their symptoms were mild. None of the children developed herpes-zoster during the 6 year follow-up period. The results suggest that the varicella vaccine is effective in children with acute leukemia, and that long-term effectiveness can be expected.     

Effect and follow-up study on varicella vaccine

Attenuated liver varicella vaccine (Oka strain) was used to vaccinate 242 children and 5 adults between August 1976 and December 1982; namely emergency vaccinations were given to 163 cases, including 35 high risk children, on 17 occasions, and non-emergency vaccinations were given to 84 cases including 7 high risk ones in remission. The viral doses varied from 250 to 3,000 PFU. Vaccinations prevented subsequent infection in all cases. Emergency vaccinations were given within 100 h after contact of the subjects with cases of varicella. Humoral and/or cellular immunity was acquired in 97.6% (40/41) of the high risk group and 91.8% (179/195) of the non-high risk group. As clinical reactions, rashes and fever developed in 43.9% (18/41) and in 17.0% (7/41) of high risk patients, and 7.8% (16/204) and 1.0% (2/204) of the non-high risk patients respectively. Reactions were generally slight, but were severe or atypical in 3 immunocompromized patients. Follow-up studies were carried out every year since 1980. Among the 41 high risk patients, herpes-zoster developed in 4, and varicella in 5 patients. Among the 179 non-high risk patients, there were no cases of herpes-zoster but 21 cases (12.3%) of varicella, which were mostly extremely mild. Six patients were revaccinated because of their humoral and/or cellular immunity decreased, and as a result acquired an immune response again. Criteria for varicella vaccination and details of the results of vaccination and follow-up studies are described.     

Prevention of varicella in urgent cases by passive transfer of vaccine-induced immunity

For the purpose of preventing spread of infection to high risk children whose immunities were severely impaired by intensive chemotherapy or for some other reason, when cases of varicella occurred in a children's ward or in a family, healthy adults (mothers and a doctor) were immediately given live varicella vaccine, blood was collected from these adults 5 to 7 days after vaccination and the whole blood or plasma including the buffy coat was transferred in the high risk children. Subsequently the children showed little or no clinical reaction, and follow-up studies by the neutralizing test and skin test with varicella antigen indicated that their inapparent or subclinical varicella infection occurred in them and that their immunity to varicella was lasting. Skin tests with varicella antigen showed that booster reaction occurred in adults with a previous history of varicella as early as 5 to 7 days after vaccination. The cellular immunity thus induced in the donors may have played a role in preventing a clinical reaction in the high risk children. Thus passive transfer of vaccine-induced immunity seems a convenient and effective method for preventing infection in subjects whose immune capacities are severely impaired.     

Development and characterization of a live varicella vaccine (Oka strain)

A live varicella vaccine (Oka strain) was developed by serial passage of the Oka strain isolated in our laboratory, in human embryonic lung cells (11 times at 34 C) and guinea pig embryo cells (12 times at 37 C). It is slightly temperature sensitive at 39 C and shows a higher ratio of infectivity in guinea pig embryo cells to infectivity in human embryo cells than wild-type strains. The DNA digest with Hpa I enzyme of the Oka strain contained one unique fragment (K), although its mobility differed only slightly from that of the corresponding fragment of wild-type strains. Studies with clinical varicella zoster virus (VZV) isolates from vaccinees indicated that tests on the ratio of infectivity in guinea pig embryo fibroblasts (GPEF) to that in human embryo fibroblasts (HuEF) and the profile of the DNA digest with Hpa I are useful for differentiation of the vaccine strain from wild-type strains. The vaccine virus showed stable immunogenicity during at least 15 further repeated passages in human diploid cells, a character which seems helpful for production of a large quantity of vaccine virus for practical use.     

A clinical trial of live attenuated varicella vaccine (Biken) in children with malignant diseases

The live attenuated varicella vaccine (Biken) derived from the Oka strain was used for immunization of childhood cancer patients in remission but on chemotherapy. Thirty nine patients were immunized without any severe adverse effects but 6 recipients had a small number of vesicles. Seroresponses were observed in 90% of recipients examined. During the follow-up period 6 leukemia recipients were suffered from natural varicella in family or community contacts. No vaccinee developed herpes-zoster during this study period.     

Use of live varicella vaccine in children with acute leukemia and malignant lymphoma

Live varicella vaccine was given to 7 children with acute leukemia and 1 child with non-Hodgkin's lymphoma. Seroconversion without any clinical reactions was observed in 4 children in remission from acute leukemia without interruption of anticancer medication. These children have been free from varicella for 5 to 11 months after vaccination. Mild to severe clinical reactions developed in 3 of 4 children who were receiving remission induction chemotherapy. It is concluded that live varicella vaccine is effective in children with acute leukemia without interrupting anticancer medication, but that it is not suitable for children with leukemia and lymphoma who are receiving remission induction chemotherapy with antileukemic agents.     

Varicella vaccination: evidence for frequent reactivation of the vaccine strain in healthy children

Wild-type varicella zoster virus (VZV) causes chickenpox, a common childhood illness characterized by fever and a vesicular rash and rare serious complications. Wild-type VZV persists in a latent form in the sensory ganglia, and can re-activate to cause herpes zoster. More than 10 million American children have received the live attenuated Oka strain VZV vaccine (OkaVZV) since its licensure in 1995. Pre-licensure clinical studies showed that mean serum anti-VZV levels among vaccinees continued to increase with time after vaccination. This was attributed to immunologic boosting caused by exposure to wild-type VZV in the community. Here, we examine the alternative, that large-scale asymptomatic reactivation of OkaVZV might occur in vaccinees. We analyzed serum antibody levels and infection rates for 4 years of follow-up in 4,631 children immunized with OkaVZV. Anti-VZV titers decreased over time in high-responder subjects, but rose in vaccinees with low titers. Among subjects with low anti-VZV titers, the frequency of clinical infection and immunological boosting substantially exceeded the 13%-per-year rate of exposure to wild-type varicella. These findings indicate that OkaVZV persisted in vivo and reactivated as serum antibody titers decreased after vaccination. This has salient consequences for individuals immunized with OkaVZV.     

二代测序法深度分析水痘疫苗Oka株病毒基因特征

采用二代测序(next-generation sequencing,NGS)技术,对上海生物制品研究所有限责任公司(简称SIBP)2015-2017这3个年度生产的Oka株水痘疫苗进行深度测序,从分子水平分析疫苗质量的一致性,并与不同厂家疫苗/毒种进行比较,分析它们之间的遗传特征相关性。结果显示,3个年度生产的水痘疫苗中平均有77个位点的疫苗型位点检出频率(proportion of vaccine-type allele,Pv)≥10%,至少在两批疫苗中出现Pv≥10%的位点数共76个,两两之间Pv最大差值<10%,与平均值的最大差值为<5%。共有40个位点的Pv均值≥30%,其中19个位点导致氨基酸残基变异;15个位于ORF62区域。筛选出35个位点,比较5个公司水痘疫苗/毒种的Oka株病毒基因序列,结果显示它们之间存在相关性,同时存在一定的差异。研究表明,SIBP不同年度生产的水痘疫苗Oka株病毒具有良好的分子水平上的一致性,为疫苗质量管理与市场监督提供了方法和基础数据。     

Oka株水痘病毒的生物学特性研究

将日本大阪大学微生物病研究会（BIKEN）提供的Oka水痘病毒第28代减毒株,通过MRC－5人二倍体细胞连续传递10代,建立主代及工作代毒种批,并对其后的32代,34代,36代及38代病毒按WHO规程进行全面检定,证实其生物学特性相似,免疫原性良好,确保制备水痘减毒活疫苗毒种的稳定性和一致性。     

Delayed-type hypersensitivity and in vitro lymphocyte response in guinea pigs immunized with a live varicella vaccine

The relation of delayed type hypersensitivity (DTH) assessed by the Varicella-Zoster virus (VZV) skin test and lymphocyte transformation (LTF) with VZV antigen was investigated in guinea pigs immunized with live varicella vaccine virus, or heat-inactivated vaccine virus. Guinea pigs immunized with live varicella vaccine virus showed positive DTH and LTF responses to viral antigen as well as a neutralizing (NT) antibody response, while those immunized with heat-inactivated vaccine virus showed only an NT antibody response of the same degree as that to live vaccine virus. These results show the reliability of the skin test in assessing cell-mediated immunity (CMI) to VZV and the advantage of the live varicella vaccine over the inactivated one in immunizing guinea pigs.