Oka Vaccine Strain Research Articles

Late-Onset Concurrent Infection of Vaccine Strain VZV and HSV-1 after Varicella Vaccination in a Child with Natural killer T Cell Deficiency

AbstractWe describe a case with natural killer cell deficiency of late-onset Oka vaccine varicella zoster virus (VZV) strain and Herpes simplex virus-1 (HSV-1) dual infection resulting in fatal clinical course. An 18-month-old boy presented with a papulovesicular rash, mucocutaneous candidiasis, encephalopathy, and severe respiratory distress 6 months after receiving varicella vaccine. VZV and HSV-1 were analysed by real-time reverse-transcriptase polymerase chain reaction (RT-qPCR) and Oka vaccine strain of VZV by gene sequencing. HSV-1 and VZV dual infection was detected in the blood and skin samples by RT-qPCR. Gene sequencing of VZV isolated from vesicular lesions was compatible with the Oka vaccine strain. Flow cytometry revealed a natural killer deficiency, but whole exome analysis failed to identify an associated genetic defect. Vesicular rashes in immunocompromised patients who were inadvertently vaccinated should be taken seriously, and antiviral therapy should be prompt and aggressive.

Safety and immunogenicity of a skin- and neuro-attenuated live vaccine for varicella: a randomized, double-blind, controlled, dose-escalation and age de-escalation phase 1 clinical trial

Despite the success in decreasing varicella-related disease burden, live-attenuated Oka vaccine strain of varicella-zoster virus (vOka) remains neuro-virulence and may establish latency and reactivate, raising safety concerns. Here we aimed to evaluate the safety and immunogenicity of a skin- and neuro-attenuated varicella vaccine candidate (v7D). This is a randomized, double-blind, placebo-controlled, dose-escalation and age de-escalation phase 1 clinical trial conducted in Liuzhou, China (ChiCTR1900022284). Eligible healthy participants aged 1-49 years, with no history of varicella vaccination and had no history of varicella or herpes zoster were sequentially enrolled and allocated to subcutaneously receive one of the three doses (3.3, 3.9, and 4.2 lg PFU) of v7D, vOka or placebo in a dose-escalation and age de-escalation manner. The primary outcome was safety, assessed by adverse events/reactions within 42 days after vaccination and serious adverse events (SAEs) throughout six months after vaccination. The secondary outcome was immunogenicity, assessed by the VZV IgG antibodies measured with fluorescent antibody to membrane antigen (FAMA) assay. Between April 2019 and March 2020, totally 224 participants were enrolled. Within 42 days post-vaccination, the incidences of adverse reactions were 37.5%-38.7% in the three doses of v7D groups which were similar to that of the vOka (37.5%) and placebo (34.4%) groups. No SAE has been judged as causally related to vaccination. At 42 days post-vaccination, 100% of children aged 1-12 years in the per-protocol set of immunogenicity cohort of the v7D groups became seropositive. Meanwhile, in the intent-to-treat set of immunogenicity cohort of subjects aged 1-49 years, the geometric mean increases of the three groups of v7D vaccine were 3.8, 5.8 and 3.2, respectively, which were similar to that of the vOka vaccine group (4.4) and significantly higher than that of the placebo group (1.3). The candidate v7D vaccine has been preliminarily shown to be well-tolerated and immunogenic in humans. The data warrant further evaluation of the safety advantage and efficacy of v7D as a varicella vaccine. The National Natural Science Foundation of China, CAMS Innovation Fund for Medical Sciences, and Beijing Wantai CO., LTD.

Vaccine-derived varicella zoster infection in a kidney transplant recipient after zoster vaccine live administration

A 49-year-old kidney transplant recipient, presented with a skin rash, and interstitial infiltrates three weeks after receiving a live attenuated varicella-zoster vaccine. Varicella-zoster Oka-vaccine strain was detected in plasma by polymerase chain reaction and sequencing analysis targeting open reading frame 62 (ORF 62). She was treated successfully with intravenous acyclovir. Our case report supports the current contraindication of live attenuated varicella-zoster vaccine in the solid-organ transplant recipients. Recombinant subunit varicella-zoster vaccine may be the vaccine of choice in these patients; nevertheless, further information is required to establish its safety, efficacy, and optimal timing.

Comparison of the Whole-Genome Sequence of an Oka Varicella Vaccine from China with Other Oka Vaccine Strains Reveals Sites Putatively Critical for Vaccine Efficacy

Varicella-zoster virus (VZV) infection results in varicella mostly in children. Reactivation of the virus causes herpes zoster (HZ), mostly in adults. A live attenuated vaccine (vOka-Biken) was originally derived from the parental strain pOka. Several live attenuated vaccines based on the Oka strain are currently available worldwide. In China, varicella vaccines have been licensed by four manufacturers. In this study, we analyze the whole-genome sequence (WGS) of vOka-BK produced by Changchun BCHT Biotechnology also known as Baike. vOka-BK WGS was compared against the genomic sequences of four other Oka strains: pOka, vOka-Biken, vOka-Varilrix from GlaxoSmithKline, and vOka-Varivax from Merck & Co. A previous study identified 137 single nucleotide polymorphisms (SNPs) shared by all vOkas. The current analysis used these data as a reference to compare with vOka-BK WGS and focused on 54 SNPs located in the unique regions of the genome. Twenty-eight nonsynonymous substitutions were identified, ORF62 and ORF55 featuring the most amino acid changes with 9 and 3, respectively. Among the 54 SNPs, 10 had a different mutation profile in vOka-BK compared to the other three vaccines. A comparison with the clade 3 strain Ellen, known to be attenuated, identified three shared amino acid changes: *130R in ORF0 and R958G and S628G in ORF62. This analysis provides the first comparison of a Chinese varicella vaccine to the other vaccines available worldwide and identifies sites potentially critical for VZV vaccine efficacy.IMPORTANCE Varicella, also known as chickenpox, is a highly contagious disease, caused by varicella-zoster virus (VZV). Varicella is a common childhood disease that can be prevented by a live attenuated vaccine. The first available vaccine was derived from the parental Oka strain in Japan in 1974. Several live attenuated vaccines based on the Oka strain are currently available worldwide. Among the four vaccines produced in China, the vaccine manufactured by Changchun BCHT Biotechnology, also known as Baike, has been reported to be very efficacious. Comparative genomic analysis of the Baike vaccine with other Oka vaccine strains identified sites that might be involved in vaccine efficacy, as well as important for the biology of the virus.

Severe and Complicated Varicella and Associated Genotypes 10 Years After Introduction of a One-Dose Varicella Vaccine Program.

This national, sentinel prospective study aimed to identify children with severe hospitalized varicella, despite availability of universal 1-dose vaccination since 2005, and determine associations between virus genotypes and disease severity. Children with varicella or zoster from 5 Paediatric Active Enhanced Disease Surveillance hospitals were enrolled. Lesions were swabbed for genotyping. Associations with disease severity were analyzed using multiple regression. From 2007 to 2015, 327 children with confirmed varicella (n = 238) or zoster (n = 89) were enrolled. Two hundred three (62%) were immunocompetent children; including 5 of 8 children who required intensive care unit management. Eighteen percent (36 of 203) of immunocompetent children had been previously vaccinated. Vaccinated children aged >18 months were less likely to have severe disease (9%; 5 of 56) than unvaccinated children (21%; 21 of 100; P = .05). Three of 126 children who had virus genotyping (2 immunocompromised) had varicella (n = 2) or zoster (n = 2) due to the Oka/vaccine strain. European origin clades predominated and were independently associated with more severe disease (odds ratio = 3.2; 95% confidence interval, 1.1- 9.5; P = .04). Severe hospitalized varicella still occurs with a 1-dose varicella program, although predominantly in unvaccinated children. Most 1-dose vaccine recipients were protected against severe disease. Viral genotyping in complex hospitalized cases is important to assist in monitoring disease due to Oka-vaccine strain.

Evaluating the effectiveness of the universal immunization program against varicella in Japanese children.

Matched case control study was conducted to elucidate the effectiveness of the Oka/Biken vaccine immediately after implementation of the universal immunization program in Japan. Cases were laboratory confirmed varicella patient under 15years of age diagnosed at 14 designated pediatric clinics between September 2015 and September 2016. Controls were selected from patients who visited the same practice for different reasons as the varicella case within 2weeks. Swab samples were collected from varicella suspected patients and molecular diagnostic assays were used to confirm varicella cases. Matched odds ratio were used to calculate vaccine effectiveness (VE). Varicella zoster virus DNA was detected in 183 (81.3%) of 225 suspected cases. One sample was excluded because it was positive for the Oka vaccine strain (182/225, 80.9%). Three hundred twenty-three control subjects were enrolled. The effectiveness of 1 dose of the Oka/Biken vaccine compared with no vaccine was 76.7% (95% confidence interval [CI]: 58.6-86.9%; P<0.001). The effectiveness of 2 doses of the Oka/Biken vaccine was 94.2% (95% CI: 85.7-97.6%; P<0.001). After adjusting for potential confounding effects, the adjusted VE of 1 and 2 doses of varicella vaccine were 76.9% (95% CI: 58.1-87.3%; P<0.001) and 94.7% (95% CI: 86.0-98.0%; P<0.001), respectively. VE of one dose of Oka/Biken varicella vaccine was insufficient to control varicella. Therefore, two doses of Oka/Biken varicella vaccine is significant for controlling varicella in Japan.

Identification of Varicella-Zoster Virus Infections Caused by Oka Vaccine Strain and Genotype Analysis in Children

Identification of Varicella-Zoster Virus Infections Caused by Oka Vaccine Strain and Genotype Analysis in Children

Safety profile of the varicella vaccine (Oka vaccine strain) based on reported cases from 2005 to 2015 in Japan

BackgroundAs of 2014, routine vaccination strategies in Japan have included the varicella vaccine. Given the widespread use of the vaccine, it is important to investigate the safety profile of the vaccine strain, Oka/Biken varicella, in Japanese patients. MethodsReports of adverse events associated with varicella vaccination between 2005 and 2015 were retrospectively reviewed. Virological analysis was performed on clinical specimens collected from some of the reported cases to determine whether the etiological agent was the wild-type or Oka vaccine–strains. ResultsThere were 351 reports (3.71/100,000 doses) of adverse events during the observation period. Among the 351 reports, there were 88 reports (0.93/100,000 doses) of varicella-like and 66 reports (0.70/100,000 doses) of zoster-like skin rashes. The wild-type strain induced varicella-like skin rashes earlier than the Oka vaccine strain. The Oka vaccine strain induced zoster-like skin rashes in younger patients compared to the wild-type strain. The onset of zoster-like skin rashes after vaccination was earlier in patients vaccinated with the Oka vaccine–type strain. ConclusionThe Oka/Biken vaccine is generally safe and well tolerated in Japan. Clinical aspects of adverse reactions caused by the Oka vaccine strain were consistent with previous reports from the United States and Europe.

Fatal disseminated varicella zoster infection following zoster vaccination in an immunocompromised patient

A 79-year-old man with chronic lymphocytic leukaemia presented with fever and a widespread vesicular rash on 19 November 2014. The patient had not been under immunosuppressive regime for 6 months. He had received a shingles vaccine on 14th October and developed flu-like symptoms after 2 weeks. Intravenous antimicrobial therapy including aciclovir was started. He remained stable with no evidence of systemic involvement. On day 5, he developed respiratory and renal failure that required transfer to intensive care unit. Vesicle fluid, bronchoalveolar lavage and plasma were positive for varicella zoster virus by PCR. Slight clinical improvement allowed extubation on day 16. He subsequently deteriorated and died on day 25. Multiorgan failure was considered the immediate cause of death whereas disseminated varicella zoster infection was stated in the medical certificate as the other condition leading to this outcome. Varicella zoster Oka vaccine strain was detected in vesicle fluid, using PCR.

A recombinant varicella vaccine harboring a respiratory syncytial virus gene induces humoral immunity

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is highly efficient and causes few adverse events; therefore, it is used worldwide. We previously constructed recombinant vOka (rvOka) harboring the mumps virus gene. Immunizing guinea pigs with rvOka induced the production of neutralizing antibodies against the mumps virus and VZV.Here, we constructed recombinant vOka viruses containing either the respiratory syncytial virus (RSV) subgroup A fusion glycoprotein (RSV A–F) gene or RSV subgroup B fusion glycoprotein (RSV B–F) gene (rvOka-RSV A–F or rvOka-RSV B–F). Indirect immunofluorescence and Western blot analyses confirmed the expression of each recombinant RSV protein in virus-infected cells. Immunizing guinea pigs with rvOka-RSV A–F or rvOka-RSV B–F led to the induction of antibodies against RSV proteins. These results suggest that the current varicella vaccine genome can be used to generate custom-made vaccine vectors to develop the next generation of live vaccines.

Novel polyvalent live vaccine against varicella–zoster and mumps virus infections

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is a highly immunogenic and safe live vaccine that has long been used worldwide. Because its genome is large, making it suitable for inserting foreign genes, vOka is considered a candidate vector for novel polyvalent vaccines. Previously, a recombinant vOka, rvOka-HN, that expresses mumps virus (MuV) hemagglutinin-neuraminidase (HN) was generated by the present team. rvOka-HN induces production of neutralizing antibodies against MuV in guinea pigs. MuV also expresses fusion (F) protein, which is important for inducing neutralizing antibodies, in its viral envelope. To induce a more robust immune response against MuV than that obtained with rvOka-HN, here an rvOka expressing both HN and F (rvOka-HN-F) was generated. However, co-expression of HN and F caused the infected cells to form syncytia, which reduced virus titers. To reduce the amount of cell fusion, an rvOka expressing HN and a mutant F, F(S195Y) were generated. Almost no syncytia formed among the rvOka-HN-F(S195Y)-infected cells and the growth of rvOka-HN-F(S195Y) was similar to that of the original vOka clone. Moreover, replacement of serine 195 with tyrosine had no effect on the immunogenicity of F in mice and guinea pigs. Although obvious augmentation of neutralizing antibody production was not observed after adding F protein to vOka-HN, the anti-F antibodies did have neutralizing activity. These data suggest that F protein contributes to induction of immune protection against MuV. Therefore this recombinant virus is a promising candidate vaccine for polyvalent protection against both VZV and MuV.

Cycling probe technology to quantify and discriminate between wild-type varicella-zoster virus and Oka vaccine strains

Rapid differentiation between wild-type varicella zoster virus (VZV) and Oka-vaccine (vOka) strains is important for monitoring side reactions of varicella vaccination. To develop a high-throughput molecular diagnostic method for the differentiation of wild-type VZV and vOka strains based on cycling probe technology. The primers were designed to amplify common sequences spanning a single nucleotide polymorphism (SNP) in gene 62 of VZV. DNA–RNA chimeric probes (cycling probes) were designed to detect the SNP at nucleotide 105705. The cycling probe real-time PCR assays for VZV wild-type and vOka strains specifically amplified plasmids containing target sequences that ranged between 10 and 1×106 copies per reaction. The inter- and intra-assay coefficients of variation were less than 5%. After initial validation studies, the clinical reliability of this method was evaluated using 38 swab samples that were collected from patients suspected of being zoster. Compared to the loop mediated isothermal amplification method, which is defined as the gold standard, cycling probe real-time PCR was highly sensitive and specific. The cycling probe real-time PCR technology is a reliable tool for differentiating between wild-type VZV and vOka strains in clinical samples.

The case for Zostavax vaccination in systemic lupus erythematosus

Data published thus far demonstrate that the HZ vaccine has been well tolerated by most individuals, immunocompetent and immunocompromised. It is currently licensed for healthy adults ≥ 50 years old. In the healthy population, advancing age is the greatest risk factor for the development of HZ, with highest rates seen in those ≥70 years of age, likely due to age-related diminution of CMI. HZ incidence is higher in SLE patients compared to healthy people at all ages. Hence, SLE patients, even as young adults, have higher reported HZ incidence than 80 year-old healthy adults, and should be considered a similar high-risk population who are most likely to derive meaningful benefit from vaccination. Even if the efficacy of vaccination in the SLE population proves to be less than seen in the immunocompetent elderly population, the reduction in incidence and severity of both acute HZ and PHN will provide benefit. Until results of randomized clinical trials of Zostavax in SLE patients are reported, we must rely on clinical assessment of potential risks and benefits of vaccinating this population. Risks of complications directly attributible to zoster vaccination, including the theoretic possibility of vaccine-induced infection, can be mitigated by several means. First, prior exposure to VZV can be easily confirmed by commercially available serology, thereby avoiding the introduction of live-attenuated VZV into naive patients. In these subjects, the varicella vaccine (Varivax (Merck) or Varilrix (GlaxoSmithKline)), which has significantly lower potency than Zostavax and is intended for primary prevention of varicella, may be considered. Vaccination should be delayed until acute flares have resolved and induction therapy has been completed and patients are receiving only maintenance immunosuppressive therapy. Discontinuing disease modifying therapy for the sole purpose of vaccination should only be undertaken after careful consideration of the risks of inducing flare of underlying disease after withdrawal of therapy. Finally, the OKA vaccine strain was attenuated by serial passages in cell cultures and is avirulant as compared to wild type strains. Furthermore, it is susceptible to standard antiviral therapy, shall any vaccine-induced infection occur. Clinical trials addressing the safety and efficacy of Zostavax in SLE will provide more definitive information upon which to base vaccination decisions. However, results remain years away. In the mean time, vaccination among stable SLE patients ≥50 years old should be strongly considered.

Herpes zoster nach Varicella-Zoster-Virus-Impfung

A five-year-old girl, vaccinated against varicella-zoster virus (VZV) presented with clinical symptoms of herpes zoster in the 6th cervical dermatome. A VZV direct immune-fluorescence assay was negative three times but additional genotypical analysis showed a VZV strain genotype 2 (Oka vaccine strain). Therefore the diagnosis of a breakthrough varicella disease with the vaccine strain was established. An immunodeficiency was ruled out and the patient responded well to the initiated therapy. This case demonstrates that a negative VZV direct immunofluorescence assay does not exclude an infection with the vaccine strain.

Sequencing and characterization of Varicella-Zoster virus vaccine strain SuduVax

Varicella-zoster virus (VZV) causes chickenpox in children and shingles in older people. Currently, live attenuated vaccines based on the Oka strain are available worldwide. In Korea, an attenuated VZV vaccine has been developed from a Korean isolate and has been commercially available since 1994. Despite this long history of use, the mechanism for the attenuation of the vaccine strain is still elusive. We attempted to understand the molecular basis of attenuation mechanism by full genome sequencing and comparative genomic analyses of the Korean vaccine strain SuduVax. SuduVax was found to contain a genome that was 124,759 bp and possessed 74 open reading frames (ORFs). SuduVax was genetically most close to Oka strains and these Korean-Japanese strains formed a strong clade in phylogenetic trees. SuduVax, similar to the Oka vaccine strains, underwent T- > C substitution at the stop codon of ORF0, resulting in a read-through mutation to code for an extended form of ORF0 protein. SuduVax also shared certain deletion and insertion mutations in ORFs 17, 29, 56 and 60 with Oka vaccine strains and some clinical strains. The Korean VZV vaccine strain SuduVax is genetically similar to the Oka vaccine strains. Further comparative genomic and bioinformatics analyses will help to elucidate the molecular basis of the attenuation of the VZV vaccine strains.

Reporter cell line-based screening for anti-varicella-zoster virus compounds

Objective To establish a novel method to screen for anti-varicella-zoster virus (VZV) compounds with our previously generated reporter cell line for VZV, MV9G. Methods MV9G cells were directly infected with cell-free virus of Oka vaccine strain (vOka) for 2 hours( CFV direct-infection) or cocultured with vOka-infected MeWo cells containing cell-associated virus for 48 hours (CAV co-culture) to promote expression of the reporter gene firefly luciferase. Antiviral compounds including heparin, mannose-6-phosphate( M-6-P), acyclovir( ACV ), resveratrol and roscovitine were added in the medium before or after the virus infection. Inhibitory effects( IC50 ) of the antiviral compounds were analyzed by comparing firefly luciferase activities of MV9G cells in the presence of antiviral compounds with those in the absence. Results Antiviral compounds inhibited luciferase activities of MV9G cells activated by CFV direct-infection and/or CAV co-culture in different levels. The reductions of luciferase activities statistically correlated with those of viral foci shown by immunostaining with a monoclonal antibody against VZV immediate early 62 antigens (IE62) in controls. Among these compounds, heparin, M-6-P, and 2.5 μmol/L of roscovitine inhibited CFV-activated more strongly than CAV-activated luciferase activities, whereas ACV and resveratrol inhibited CAV-activated more strongly than CFV-activated luciferase activities. Cell-associated ACV-resistant strains,Kanno and rOka YSR, activated luciferase activities of MV9G cells, too. However, the inhibitory concentrations (IC50) of ACV to the ACV-resistant strains were much higher than those to the ACV-sensitive strains,pOka and CaGu. Conclusion The CFV direct-infection and CAV co-culture assays were useful to screen for antiviral compounds targeting the early and late phases of VZV infection, respectively. The VZV reporter cell-based assays may provide a simple, rapid, sensitive, and high-throughput method to screen for anti-VZV compounds. Key words: Varicella-zoster virus; Reporter cell line; Mannose-6-phosphate; Resveratrol; Roscovitine

The History and Mystery of VZV in Saliva

The History and Mystery of VZV in Saliva

Characterization of varicella-zoster virus-encoded ORF0 gene—Comparison of parental and vaccine strains

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) differs from the parental strain (pOka) at several amino acid positions, but the mutations responsible for the attenuation of vOka have not been clearly defined. The ORF0 of vOka carries some of the mutations. Although we found that the ORF0 of both strains was incorporated into virus particles, the C-terminal region of vOka ORF0 was presented on the virion surface and was N-glycosylated, suggesting that the mutation in vOka ORF0 changes it into a novel envelope glycoprotein. In a mutant virus in which pOka ORF0 was replaced by vOka ORF0, the molecular weight of ORF0 was altered, but the plaque size was not. In addition, a pOka recombinant virus lacking the hydrophobic domain of ORF0 grew equally well as the wild-type virus, indicating that the mutation in ORF0 is not by itself sufficient for the attenuation of the vOka virus.

The Parental Strain of the Attenuated Virus (vOka) Used in the Varicella Vaccine Is Circulating in China: Implications for Vaccine Surveillance

Varicella-zoster virus (VZV) is the etiological agent of both varicella (chickenpox) and herpes zoster (shingles). Primary infection with VZV causes varicella, which usually occurs in childhood. Reactivation of VZV in previously infected individuals results in a herpes zoster that occurs most commonly in the elderly. In 1974, a live-attenuated VZV strain was established and subsequently licensed for vaccination in Japan (1). Comparison of the complete DNA sequences of the Oka vaccine strain (vOka) and the parental Oka strain (pOka) revealed there were only 42 nucleotide substitutions along the whole 125-kbp viral genome, 15 of which were located in the major transactivator ORF62 region (2). The high sequence homology between vOka and pOka increases the difficulty of distinguishing vOka from clinical isolates with the pOka genotype. The pOka-like wild-type strain constitutes 20–30% of all VZV isolates in Japan (3). In contrast, it seems a rare genotype in other countries such as the U.S. and Australia (4,5). In this study we report a case of herpes zoster infected by the pOka-like wild-type strain in a Chinese woman. A 27-year-old woman who was 8 months pregnant presented to the First Affiliated Hospital of Anhui Medical University (Hefei, China) with vesicle skin lesions. The diagnosis of zoster was made mainly based on the history and features of the rash. The zoster rashes had developed on the right side of her abdomen, and she had no post-herpetic neuralgia. VZV was isolated in human embryonic lung fibroblasts from vesicle fluid taken from the patient on day 2 after the onset of zoster and was identified by immunocytochemistry with monoclonal antibodies to VZV glycoprotein E (Biodesign International ® , Saco, Maine, USA). This strain is hereafter designated as ZW strain. Serologic assay by fluorescent antibody to the membrane antigen (FAMA) test revealed a specific VZV IgG antibody titer of 1:8 in the serum colleted on day 2, and 1:256 in the second serum specimen obtained 16 days after the onset of symptoms. Viral DNA was extracted from the fluid of the rash vesicles

Transmission of Varicella Vaccine Virus, Japan

Transmission of Varicella Vaccine Virus, Japan