The Immunogenicity of Varicella-zoster Virus Vaccine in HIV-infected Children
Condition: HIV Infections; Varicella-zoster Virus
MeSH terms: Herpes Zoster; Chickenpox; Varicella Zoster Virus Infection
Study type: Interventional
Phase: Phase 4

Summary: 
      To study about the immunogenicity, safety and efficacy of varicella-zoster virus vaccine in
      HIV-infected children.
    

Detailed description: 
      VZV causes two clinical diseases, primary infection results in varicella (chickenpox) after
      which virus latent in dorsal root ganglion. Reactivation of VZV results in herpes zoster
      (shingles) about years or decades. Immunocompetent children, varicella generally mild self
      limiting illness. In HIV infected children, VZV is often more severe illness with progressive
      varicella characterized by continuing eruption of lesions and high fever persist into second
      weeks, as well as encephalitis, hepatitis and pneumonia can developed. Zoster in
      immunocompromised patient become disseminated with lesions appearing outsides primary
      dermatomes and with visceral complications and can cause recurrences of herpes zoster. VZV
      illness in patients with immunodeficiency disorders require admission to hospital and the use
      of antiviral drugs. Sometimes, antiviral drug fails in immunocompromised children. Passive
      immunization with varicella zoster-immunoglobulin (VZIG), administered within three days of
      exposure, is effective in preventing disease or in reducing severity of illness in
      susceptible immunocompromised persons. About half of the cases of varicella in
      immunocompromised children occur without a recognised exposure to VZV. Both severe and fatal
      varicella has been documented despite appropriate immunoprophylaxis withVZIG. Furthermore,
      VZIG is expensive and short supply. These limitations make passive immunization a less than
      optimum strategy for preventing chickenpox. Permanent protection provided by administering
      the vaccine to high-risk persons would be preferable.

      Sartori AM., University of Sao Paolo in Sep 2004 found that after give two doses of the
      varicella vaccine in 41 susceptible HIV-infected childrens in CDC class N1 or A1.
      Seroconversion occurred in 53% and 60% of vaccines after one and two doses, respectively. No
      significant fall in CD4 T lymphocytes or increase in HIV viral load at eight weeks after
      vaccination.

      Saro H. Armenian, University of Southern California in Nov 2005 administrated single dose of
      live varicella vaccine to 10 HIV infected children. After vaccination, positive VZV-LPA
      response was detected in 50% of patients at week 2 and 100% at week 4, remained positive in
      90% at week 52. VZV IgG was detected in 11% at week 2, 67% at week 8, only 33% at week 52.

      Myron J. Levin, University of Colorado in June 2006-2008 study about the safety and
      immunogenicity of vaccine in varicella-zoster virus (VZV) naive, HIV-infected children with
      moderate symptoms and/or more pronounced past or current decreases in CD4+ T cell counts.
      Recipients (97 children) were stratified into 3 groups : group I - CDC category 1 and
      immunologic category 1 (least affected group of HIV-infected children), group II - CDC
      category A, B, or N and immunologic category 2 (CD4% = 15-24), group III : CDC category C
      and/or immunologic category 3, but at least 3 months prior to vaccination, had achieved
      clinical category A or N and equivalent of immunologic category 1 (CD4% = 25). After 2 doses
      of vaccines , 79% of children developed VZV-specific antibody and/or CMI 2 months after
      vaccine and 83% were responders 1 year after vaccination. Bekker V., Emma Children's
      Hospital, Netherland in Nov 2006 administered 2 doses of varicella vaccine to 15
      VZV-seronegative HIV-1 infected children (total lymphocyte counts > 700 lymphocytes/microl)
      and 6 HIV-negative VZV-seronegative. Only 60% of the HIV-1 infected children had VZV-specific
      Ab after two immunizations, where as 100% of the siblings seroconverted.

      Thai HIV infected children usually start antiretroviral late due to limited access to care
      with more severe suppressed of immune status than children in developed countries. Moreover,
      VZV vaccine is not in the country guideline and still expensive. We would like to provide VZV
      prevention for this group of children and to evaluate the VZV antibody response in Thai HIV
      children after VZV vaccination.
    

Intervention name(s): VZV vaccination
Intervention type(s): Biological
Intervention description(s): Dose : 0.5 ml Route : subcutaneous injection (SC)
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: varicella-zoster virus vaccine; varicella-zoster virus antibody; immunogenicity; safety and efficacy; HIV-infected children; Assess protective VZV Antibody; Adverse events from VZV vaccine