title: [Results of Booster Vaccination in Children with Primary Vaccine Failure after Initial Varicella Vaccination].
abstract: In October 2014, the varicella vaccination policy in Japan was changed from a single voluntary inoculation to two routine inoculations. This paper reports the results of booster vaccination in children who did not show seroconversion after initial vaccination (i.e., primary vaccine failure : PVF) over a 7-year period prior to the introduction of routine varicella vaccination. Between November 2007 and May 2014, 273 healthy children aged between 1.1 and 14.5 years (median : 1.7 years) underwent varicella vaccination. Before and 4 to 6 weeks after vaccination, the antibody titers were measured using an immune adherence hemagglutination (IAHA) assay and a glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). In addition, side reactions were examined during the four-week period after vaccination. Children who did not show IAHA seroconversion (PVF) were recommended to receive a booster vaccination, and the measurement of antibody titers and an assessment of side reactions were performed after the booster dose. In May 2015, a questionnaire was mailed to each of the 273 participants to investigate whether they had developed varicella and/or herpes zoster after vaccination. After initial vaccination, the IAHA seroconversion rate was 75% and the mean antibody titer (Log2) with seroconversion was 4.7, while the gpELISA seroconversion rate was 84% and the mean antibody titer (Log10) with seroconversion was 2.4. Among children with PVF, 54 received booster vaccination within 81 to 714 days (median : 139 days) after the initial vaccination. After booster vaccination, the IAHA seroconversion rate was 98% and the mean antibody titer (Log2) with seroconversion was 5.8. Both the seroconversion rate and the antibody titer were higher compared with the values after the initial vaccination (p < 0.01). After booster vaccination, the gpELISA seropositive rate was 100% and the mean positive antibody titer (Log 10) was 3.6 ; similar results were obtained for the IAHA assay, with a significantly higher, antibody response than that after the initial vaccination (p < 0.01). Side reactions were generally minor, including fever (≥ 37.5 degrees C), rash at the injection site, and rash at other sites. There were no significant differences in the incidences of side reactions between the initial and booster vaccinations. A total of 185 participants responded to the questionnaire (response rate : 68%), and the period between receiving the initial vaccination and their response to the questionnaire ranged from 1.0 to 7.5 years (median : 4.0 years). The prevalence of breakthrough varicella after the initial vaccination was 17% among seroconverters who did not receive booster vaccination and 14% among non-seroconverters who received booster vaccination, showing no significant difference between the two groups. In conclusion, there are no safety issues regarding the administration of a booster vaccination to children with PVF after an initial varicella vaccination, and,a good antibody response can be expected.
authors.forename: Takao
authors.initials: T
authors.lastname: Ozakiv
authors.forename: Naoko
authors.initials: N
authors.lastname: Nishimura
authors.forename: Kensei
authors.initials: K
authors.lastname: Gotoh
authors.forename: Keiji
authors.initials: K
authors.lastname: Funahashi
authors.forename: Hironori
authors.initials: H
authors.lastname: Yoshii
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Okuno
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000032:analysis / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D002644:Chickenpox / Q000276:immunology* / Q000517:prevention & control; D019433:Chickenpox Vaccine / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007117:Immunization, Secondary; D007223:Infant; D007564:Japan; D008297:Male
chemical_list: D000914:Antibodies, Viral; D000942:Antigens, Bacterial; D019433:Chickenpox Vaccine; C050598:vaccin