• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.229-234
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• 2006

Varicella, which is mostly a benign disease, but also can cause considerable health burden in the community, can be prevented by immunization with live attenuated varicella vaccine. Higher uptake of varicella vaccine by universal immunization in North America has apparently been associated with decline in the number of reported cases of varicella, varicella-related hospitalizations, and the number of deaths caused by complications of varicella. On the contrary, there has been some reluctance in endorsing varicella vaccine for universal immunization in most of European countries. Concerns include unanticipated outbreaks of varicella among vaccine recipients, risk of varicella among unvaccinated adults, risk of herpes zoster among vaccinees as well as unvaccinees. Recently developed measles, mumps, rubella, and varicella combination vaccine and herpes zoster vaccine that may be licensed in the upcoming years may be the solution for varicella vaccine to be utilized in a greater scale. In Korea several varicella vaccine products have been utilized since late 1980. The adoption of varicella vaccine for universal immunization since 2005 along with the changing view in varicella prevention strategy mandates more studies for immunogenecity and efficacy of varicella vaccines as well as more surveillance to delineate the changes in epidemiology of varicella in Korea.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.12-19
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• 2008

Varicella is a highly infectious disease caused by the varicella zoster virus. The varicella vaccine was developed by Michiaki Takahashi in Japan in 1974. Despite the worldwide distribution of efficient vaccines, varicella vaccination policy is extremely variable from country to country. Although varicella vaccine is not currently recommended for universal vaccination in Japan, most countries throughout Europe, and developing countries, it had been introduced into Korea in 1988 and 20 years have elapsed since its use. Currently, varicella vaccine has been most extensively used in the United States where routine 2-dose vaccination program has been recently implemented for children. Recent 2-dose schedule in the United States and the availability of combination measles-rubella-varicella vaccines may lead to future varicella vaccination policy changes in many countries. With this background, this article summarizes the current status of varicella vaccination policies worldwide and presents provisional updated recommendation of varicella vaccination in Korea.

• Pediatric Infection and Vaccine
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• v.29 no.2
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• pp.110-117
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• 2022

Herpes zoster (HZ) has been reported in immunocompetent children who received the varicella vaccine. In vaccinated children, HZ can be caused by vaccine-strain or by wild-type varicella-zoster virus (VZV). Like wild-type VZV, varicella vaccine virus can establish latency and reactivate as HZ. We report two cases of HZ in otherwise healthy 16- and 14-month-old boys who received varicella vaccine at 12 months of age. They presented with a vesicular rash on their upper extremities three to four months after varicella vaccination. In one case, a swab was obtained by abrading skin vesicles and VZV was detected in skin specimens by polymerase chain reaction. The VZV open-reading frame 62 was sequenced and single nucleotide polymorphism analysis confirmed that the virus from skin specimen was vaccine-strain. This is the first HZ case following varicella vaccination confirmed to be caused by vaccine-strain VZV in the immunocompetent children in Korea. Pediatricians should be aware of the potential for varicella vaccine virus reactivation in vaccinated young children.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.55-63
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• 2024

Purpose: A 2-dose varicella vaccination strategy has been introduced in many countries worldwide, aiming to increase vaccine effectiveness (VE) against varicella infection. In this network meta-analysis, we aimed to provide a comprehensive evaluation and an overall estimated effect of varicella vaccination strategies, via a Bayesian model. Methods: For each eligible study, we collected trial characteristics, such as: 1-dose vs. 2-dose, demographic characteristics, and outcomes of interest. For studies involving different doses, we aggregated the data for the same number of doses delivered into one arm. The preventive effect of 1-dose vs. 2-dose of varicella vaccine were evaluated in terms of the odds ratio (OR) and corresponding equal-tailed 95% confidence interval (95% CI). Results: A total of 903 studies were retrieved during our literature search, and 25 interventional or observational studies were selected for the Bayesian network meta-analysis. A total of 49,265 observed individuals were included in this network meta-analysis. Compared to the 0-dose control group, the OR of all varicella infections were 0.087 (95% CI, 0.046-0.164) and 0.310 (95% CI, 0.198-0.484) for 2-doses and one-dose, respectively, which corresponded to VE of 69.0% (95% CI, 51.6-81.2) and VE of 91.3% (95% CI, 83.6-95.4) for 1- and 2-doses, respectively. Conclusions: A 2-dose vaccine strategy was able to significantly reduce varicella burden. The effectiveness of 2-dose vaccination on reducing the risk of infection was demonstrated by sound statistical evidence, which highlights the public health need for a 2-dose vaccine recommendation.

• Pediatric Infection and Vaccine
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• v.7 no.1
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• pp.129-135
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• 2000

Purpose : We previously reported the short-term immunogenecity and safety of 47 passaged Oka strain live attenuated varicella vaccine in healthy children in 1997. Now, we conducted this two-year follow-up study to confirm the maintenance of immunity, the occurrence of natural varicella infection and the activation of vaccine induced latent infection on the same vaccine. Methods : 99 children who had been immunized by 47 passaged Oka strain live attenuated varicella vaccine in 1997 were followed up by questionnaire, and 46 children out of study group were followed up serologically. They were asked to report any instance of varicella or herpes zoster since they had been immunized. If there was any evidence of varicella or herpes zoster, they should be clinically or serologically confirmed by doctor. Also, those patients' parents were asked to report any instance of varicella or herpes zoster in their family, playmate, kindergarten, school, or other settings. The immunity to VZV was confirmed by EIA and FAMA test. Results : 6 recipients developed breakthrough varicella after exposure to VZV in family, kindergarten and school during follow-up period. However, clinical features of those patients were very mild and self limited without therapy. And none of the recipients developed herpes zoster during this observation period. The results of EIA test showed that study subjects were all seropositive except one, and the antibody titers and GMT of FAMA test were seropositively maintained in all subjects. Statistically, the antibody titers of EIA and FAMA test confirmed two years after vaccination were higher than those results confirmed one month after vaccination. Conclusion : Our study results suggest that the immunity of 47 passaged Oka strain live attenuated varicella is well maintained until 2 years later after vaccination, and mild natural infection after exposure to VZV can be occurred with low rate. There were not developing zoster in study vaccine after vaccination for two-years.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.195-201
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• 2005

Objective : The purpose of this study is to investigate the epidemiology and clinical characteristics of herpes zoster in children and adolescents in Korea and to delineate the effects of varicella vaccine on the incidence of zoster and its complication. Methods : We evaluated the clinical records of 201 patients younger than 20 years admitted for herpes zoster at four hospitals located in Kyung-Gi provine during Jul. 1995 to Jun. 2005. Results : The admitted patients for herpes zoster have increased during the past 10 years. The effects of varicella vaccine on the incidence of herpes zoster remain inconclusive in this study. Only twelve percent of the study patients had underlying diseases. In 34(17%) of 201 patients, complications were confirmed during hospitalization. Of 34 patients, meningitis occurred most frequently. Irrespective of varicella vaccination, occurrence of complications was higher in patients who had experienced varicella previously(=overt varicella infection) than patients who had not(=subclinical varicella infection). In case of no previous varicella history, we found complications to be much lower in those who had received the varicella vaccine than those who had not. Conclusion : We cannot conclude whether the varicella vaccine has an effect on the increasing incidence of zoster. We can conclude that the subclinical varicella infection or vaccination for varicella might lead to a decreased incidence of zoster complications.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.257-264
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• 1997

Purpose: We performed this study to find out short period humoral immunogenicity and safety of 47 passaged Oka strain live attenuated varicella vaccine(1,400PFU) in 12 months to 15 years aged healthy children. Methods: Ninety nine healthy chidren, who have no histories of varicella vaccination, recent chicken pox illness and contact, allergy to other vaccines and underlying severe diseases, were involved in this study from April 1997 to August 1997. 5ml blood were collected before vaccination and after vaccination from all vaccinees to measure varicella membrane antibody by FAMA, and varicella IgG antibody by EIA. And immediate reactions within 30 minutes after vaccination, local and systemic reactions within 3 days after vaccination and vaccine induced systemic illness during 6 weeks postvaccination period were observed in all vaccinees to identify side effects of study vaccine. Results: 1) 49 seronegative and 50 seropositive vaccinees were identified in both prevaccination serologic tests. 2) Serologic responses after vaccination measured by the FAMA in seronegative group showed that the mean GMT level revealed 64.0, and seroconversion rate was 97.9%. And serologic responses after vaccination measured by the FAMA in seropositive group showed that the mean GMT level(242.2) was markedly elevated comparing with the mean GMT level(9.2) of pre vaccination. 3) The results of EIA in seronegative group revealed that postvaccination mean GMT was 435.2(prevaccination GMT; 78.7), and 100% seroconversion rate. Also, the results of EIA in seropositve group showed that the mean GMT level(769.9) of postvaccination was almostly two fold hihger than the mean GMT level(419.7) of prevaccination. 4) Observed local reactions like injection sites redness, pain, hardness and itching sense were mild and disappeared within 3 days, also shorterm systemic reactions like irritability, lethargy, poor appetites and rash were not remarkable. And there were no remarkable side effects due to vaccine during study period in all vaccinees. Conclusion: We confirmed that 47 paasaged Oka strain live attenuated varicella vaccine has high shorterm humoral immunogenicity and safety. However, we need more detail and longterm humoral and cell mediated immunogenicity studies of this vaccine including clinical field trials.

• Pediatric Infection and Vaccine
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• v.14 no.2
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• pp.188-193
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• 2007

Varicella-zoster virus is a human herpesvirus that causes chickenpox (varicella), becomes latent in cranial nerve and dorsal root ganglia, and frequently reactivates to produce shingles (zoster) and postherpetic neuralgia. Varicella zoster meningitis is a rare complication after varicella zoster infection. It usually affects a patient of immunocompromised or impaired cellular immunity, is rare in a immunocompetent child. We report two cases of aseptic meningitis in association with varicella zoster, not having any complication in the immunocompetent children.

• KSBB Journal
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• v.25 no.6
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• pp.572-576
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• 2010

Biological products, such as live varicella vaccine, are composed of biological substances derived from biological organisms. It is very difficult to identify these biologics' characteristics by analysis of simple physical and chemical methods alone. So the reference material is essential in order to evaluate the quality of bilogics. The 1'st national standard for varicella live vaccine was manufactured, established in 2002 and 2003, and have been used for the manufacturer's quality control and national lot release since then. As the lack of its availability and the decrease of its stability, this study was initiated by National Institute of Food and Drug Safety Evaluation (NiFDS) in 2008 to manufacture and establish the 2nd national standard for varicella live vaccine. The candidate material was manufactured from one of domestic manufacterers and the joint research of the NiFDS and manufacturers of varicella live vaccine was conducted to estimate of the reliable virus content. In the collaborative study, 3 laboratories including NiFDS performed the virus content test more than 7 times and all assay results were statistically analyzed. The mean coefficient of variation (CV) was 1.24%, and the geometric mean titre (GMT) variation range of each laboratory was low. On the basis of the results of this study, the candidate material of 2nd national standard for varicella live vaccine was assigned a potency of 4.26 log10 pfu/0.5 mL, when reconstituted in 0.7 mL.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.1-4
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• 2008

Immunizations are among the most cost-effective and widely used public health interventions. This is a report a revision of recommendation of immunization for children by Korean Pediatric Society. Immunization. Vaccines were divided into 4 groups. 1) Vaccines that are recommended to all infants and children (BCG, hepatitis B vaccine, DTaP, Td, Polio vaccine, Japanese encephalitis vaccine, MMR, varicella vaccine, influenza vaccine [6-23 months of age], H. influenzae type b vaccine), 2) those that can be administered to all infants and children, but decision of administration is made by parents (pneumococcal conjugate vaccine, hepatitis A vaccine, influenza vaccine [healthy children ${\geq}24$ months of age], rotavirus vaccine, human papilloma virus vaccine), 3) those that should be given to high risk group (pneumococcal polysaccharide vaccine [high risk patients ${\geq}24$ months of age], influenza vaccine [high risk patients ${\geq}24$ months of age], typhoid vaccine), and 4) those administered for control of outbreaks or prevention of emerging infectious diseases. Immunization schedule recommended by Korean Pediatric Society in 2008 is presented.