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A live varicella vaccine in a pediatric community
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Live varicella vaccine immunization in children showed good long-term immunity for over 6 years. While reactions were higher in children with malignancies, vaccinated leukemic children had significantly less zoster incidence.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Varicella-zoster virus (VZV) poses risks, particularly to immunocompromised children.
- Live varicella vaccine (VZV vaccine) is used to prevent varicella.
Purpose of the Study:
- To evaluate the safety, immunogenicity, and efficacy of live varicella vaccine in children with various underlying diseases.
- To assess long-term immunity and protection against varicella and zoster.
Main Methods:
- A cohort of 663 children received live varicella vaccine over seven years.
- Clinical reactions, VZV-specific antibody levels (FAMA, IAHA), and skin-test responses were monitored.
- Incidence of clinical varicella and zoster was compared between vaccinated and unvaccinated groups, especially in children with malignancies and acute leukemia.
Main Results:
- Clinical reactions occurred in 32.4% of children with malignancies versus 0.3% in other groups.
- Immunity, detected by FAMA, IAHA, and skin-tests, persisted for over 6 years.
- Clinical varicella occurred in 12 children (8 with malignancies).
- Zoster incidence in vaccinated acute leukemia patients (9.1%) was significantly lower than in unvaccinated leukemic children (21.6%).
Conclusions:
- Live varicella vaccine is generally safe and induces long-lasting immunity in children.
- Vaccination is effective in reducing zoster incidence, particularly in high-risk groups like children with acute leukemia.
- The vaccine demonstrates a favorable safety and efficacy profile for pediatric immunization programs.
Abstract:
A total of 663 children with various underlying diseases were immunized with a live varicella vaccine at the vaccine clinic of Osaka University Hospital during a period of seven years from October, 1975. Clinical reactions after vaccination occurred in 32.4% (24/74) of the children with malignancies and in 0.3% (2/591) of those in other groups. Vaccine-induced immunity was detected for more than 6 years, by FAMA (fluorescent antibody to membrane antigen) and IAHA (immune adherence hemagglutination) tests, and a skin-test for varicella-zoster virus (VZV). During an observation period of more than 7 years, clinical varicella developed in 12 children, 8 of whom were in the group with malignancies. Zoster occurred in only 4 (9.1%) of 44 vaccinees with acute leukemia, this incidence being significantly less (p less than 0.05) than that (21.6%, 8/37) in un-vaccinated leukemic children.