The Safety of Oka Varicella in Children Prior to Solid Organ Transplantation

Recruitment & Eligibility

Inclusion Criteria

Children > 9 months of age and adolescents < 18 years of age.
Pediatric transplant candidates who are in any of the following categories:
1. listed to receive kidney, liver, heart, lung or other or solid organ transplantation in a Canadian transplant centre
2. not yet officially listed, but are regarded by their physicians as transplant candidates by virtue of their underlying diseases
No clinical history for varicella.
Seronegative for antibodies to VZV except infants 9 - 12 months of age who may be seropositive due to maternal antibodies.
Informed consent obtained

Exclusion Criteria

Previous immunization with varicella vaccine.
Any established immune deficiency (underlying disease or drug induced) or any neoplastic disease
Children on any oral and / or intravenous steroids within 3 months prior to immunization. Children on inhaled corticosteroids in excess of 800 mcg of beclomethasone dipropionate ( or equivalent ) per day.
Any exposure to varicella or herpes zoster in the previous 4 weeks involving household, playmate or hospital contacts.
Inability to delay the transplantation for up to 6 weeks following the last varicella immunization.
Presence of a person at increased risk for varicella infection in direct and unavoidable proximity with the vaccinees ( e.g. an immunocompromised sibling)
Past history of varicella or known positive antibody titer for varicella except infants 9 - 12 months of ages who may be seropositive due to maternal antibodies
Known hypersensitivity to any of the components of the vaccine, including neomycin and gelatin
Patients whose mothers are known to be seronegative and plan to become pregnant in the subsequent three months
Administration of VZIG or any other blood products in the previous six weeks (packed red blood cells excepted).
Any significant infection and/or fever at the time of vaccination
Any patient receiving or planning to receive salicylates in the six weeks after immunization
Any patient who has received any live vaccine for 6 weeks or killed vaccine for 2 weeks prior to or after the scheduled VARIVAX™ vaccination.

Study & Design

Arm && Interventions

Group	Intervention	Description
varicella vaccine (VARIVAX)	varicella vaccine (VARIVAX)	varicella vaccine (VARIVAX)

Primary Outcome Measures

Name	Time	Method
Determination of the safety of VARIVAX™	up to 6 months	All transplant recipients were monitored over the follow-up period for microbiological and clinical evidence of reactivation of other herpes group viruses.
Determination of the proportion immunized who demonstrate seroconversion and maintain humoral immunity seroconversion at 6, 12 and 24 months post-transplantation	up to 12 months	Control antigen was prepared in parallel from uninfected cells. A gpELISA antibody level of \>0.6 gpEU/mL defined seroconversion, and a gpELISA antibody level exceeding 5 gpEU/mL defined seroprotection.
Determination of the proportion immunized who demonstrate seroconversion and maintain humoral immunity seroconversion at 6, and 12 months post-transplantation	Up to 12 months	VZV-specific antibodies were measured at Merck Research Laboratories using a previously validated ELISA method that detected antibodies to VZV glycoproteins purified from VZV-infected human fibroblasts.

Secondary Outcome Measures

Name	Time	Method

Recruitment & Eligibility