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Mr Djamel Hamadache

3 rd Annual Conference of the Children’s HIV Association ‘ Young People and HIV: Back to the Future’. Mr Djamel Hamadache. Chelsea and Westminster Hospital London. Friday 15 May, The Bridgewater Hall, Manchester.

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Mr Djamel Hamadache

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  1. 3rd Annual Conference of the Children’s HIV Association ‘Young People and HIV: Back to the Future’ Mr Djamel Hamadache Chelsea and Westminster Hospital London Friday 15 May, The Bridgewater Hall, Manchester

  2. This house believes that Varicella vaccine should be given to children with HIV:Against the motion Djamel Hamadache Paediatric HIV Nurse Specialist Chelsea and Westminster Hospital

  3. Should we really vaccinate ALL children with HIV against Varicella?

  4. VZV vaccine safety and efficacy • 2 small studies (Levin et al.) • 2001: 41 HIV 1-infected children on HAART CD4 ≥ 25% • 2006: 87 HIV 1-infected children on HAART 1-8 y.o, CD4 ≥ 15-24% or ≥ 200 cells/µL and CDC stage A, B, N • CDC-ACIP recommendations 2007 • HIV 1 infected children ≥ 12-15 months • CD4 %: ≥ 15% or CD4 Count: ≥ 200cells/µL (age specific) • 2 doses 3 months apart • No MMRV Not All HIV 1-infected children should be vaccinated against Varicella

  5. Benefits of VZV vaccine on healthy children • Universal U.S. programme since 1995 and 2006 • Decreased incidence of Chicken Pox cases by 90% (Gershon, 2006) • Reduction associated hospital admission rate (i.e. 70%) (Gershon, 2006) • Good immune response 85-90% • Few adverse events (Levin, et al 2006; Gershon, 2006) • Infection with milder symptoms in vaccinated children (2-3% children) rash, seizure, SJS, HZ neuropathy

  6. Disadvantages of VZV vaccination • Universal U.S. Programme 1995 • Chicken Pox not eradicated (Offit, 2008) • Effectiveness VZV vaccine 44% (CDC) vs. 85% (Gershon, 2006) • Immunocompromised children excluded (limited Data) • Adverse events still present in healthy children

  7. Disadvantages of VZV vaccine • Public Health issue • ↘ exposure to wild type (Vaccine or not) • Breakthrough with ↗ Risk of VZV later in life (Oka strain Vs. Wild type) with complications • ↘ immunity boost with higher risk HZ (poor memory cells) (Bonmarin et al, 2008) • ↘ immunity if immunosuppression post vaccination (Hambleton, 2009) • Household transmission(if rash post VZV vaccine) • VZV naive adults

  8. Risks for HIV 1-infected children • Live attenuated vaccine (outweigh risks Vs. Benefits) • Lack data on use vaccine on adolescents with CD4≥ 200 cells/µL • Effective 80% HIV-infected children 1 year post vaccination • No data on long term efficacy in HIV infected children • No data on time for 2nd dose with risk exposure older HIV infected children to VZV • No data vaccine dose for older children

  9. Cell-mediated immunityObaro et al. 2004 Lancet • Immunological memory is key to successful immunisation • ? HIV replication + CD4 cells attrition interfere with development of memory responses • Risk of false positive CMI (Levin et al. 2006) • Risk of activation and proliferation T cells, Cytokine release and increased HIV replication with consequent immunological deterioration • HAART and degree of functional reconstitution= unclear

  10. Cell-mediated immunity • Need for use of better assays(IgG & Cellular proliferation) • FAMA 5gp: labour intensive, time consuming, poorly sensitive (false positive/ negative) • ? Elispot, HLA • If Booster • When? (CDC stage, CD4 count...) • Healthy children first? • How long does VZV vaccine last to decide when booster indicated?

  11. Herpes Zoster • Risk shifting HZ @ population level (Jumaan et al., 2005; Bonmarin, 2008) • Risk of HZ following HAART and increased life expectancy • Lack of baseline data (not a notifiable disease) Limited data on immunocompromised subjects pre & post vaccination • Risk of HZ following exposure and latency of both WT and vaccine strains

  12. How big a problem is chicken pox and Herpes Zoster in UK/IrelandCHIPS data 2008

  13. Health & social issues

  14. Induced pain

  15. Controversy around vaccination

  16. Long term efficacy of VZV vaccine

  17. Religion Vs Science

  18. Vaccination and the Law

  19. Cost-effectiveness(Brisson et al., 2003; Bonmartin et al., 2008) Universal programme Vs Targeted immunisation Potential increase HZ amongst adults Cost effectiveness and savings except when taking HZ into account Limited data on cost effectiveness with new US programme 2006 ? HZ Vaccination or ado/adults at risks, no data

  20. Summary Universal programme VZV vaccine effective, but ? Long term HIV infected children Better VZV immunity assays (humoral and cellular) Cost effective but risk of increase HZ in adulthood Related issues affecting Public Health and Society Very limited data on HIV 1 infected children and VZV vaccination

  21. Acknowledgements CHIPS Dr Alasdair Bamford Lizzie Hutchinson (Bristol) Dr Eleni Nastouli (Imperial College) Anyone else for moral support

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