USA - Before 1995 Each year 4 million people would get the chicken pox About 10,500 – 13,000 were hospitalized Majority : healthy children and 100 to 150 died adultshttp://www.cdc.gov 4Walter A., Orenstein M.D., National Immunization Program. Overview of the US Vaccination Program
Why a VZV vaccine? Varicella develops in nearly all persons living in the US • > 90% of adults immune to VZV Complications rate higher for persons ≥ 15 and < 1 years of age • Bacterial infection of skins lesions, pneumonia, dehydratation, encephalitis, hepatitis VZV vaccine licensed in several European countries (1984), Japan (1986), Korea (1988) • No safety concerns after the administration of > 2 million doses in these countries Varicella is less severe among vaccinated persons than unvaccinated persons • Afebrile, fewer vesicular lesions, shorter duration of illness Difference of incidence of herpes zoster • 18 per 100000 persons/year for vaccinated people • 77 per 100000 persons/year after natural Varicella 5MMWR, Advisory Committee on Immunization Practices (ACIP). Prevention of Varicella. July 12, 1996, Vol 45, No RR-11
Cost-effectiveness of a Routine Varicella Vaccination program for US children One dose/child under 6 30-year period following introduction $35/dose At school entry, vaccination coverage level = 97% by the 6th year Medical costs Work-loss costs • Varicella treatment : Acyclovir • Parents missing work when their children • Vaccinated people : no Acyclovir have the chickenpox ($201) • Complications • Adults contracting chickenpox Taking into account • Evidence about vaccine efficacy • Effects of expected changes in the age distribution of the disease • Empirical data on the costs of medical utilization and work loss from varicella 6Lieu, Tracy A et al. Cost-effectiveness of a Routine Varicella Vaccination program for US Children. JAMA; 1994; 271 (5), 375-381
Cost-effectiveness of a Routine Varicella Vaccination program for US children 7Lieu, Tracy A et al. Cost-effectiveness of a Routine Varicella Vaccination program for US Children. JAMA; 1994; 271 (5), 375-381
Effects of vaccinationMatthew M. Davis et al. Decline in varicella-related hospitalizations and expenditures for children and adults after introduction of 12varicella vaccine in the United States. Pediatrics; 2004; 114; 785-792.
What about France? ● Herpes zoster prevention : insufficient data ● >15 years vaccinating 11 years old children necessary to avoid 1 death, 30 severe complications and 30.000 cases ● Safety data : rash (injection site 1-4%, generalized 1-6%) ● Efficacy data : single-dose vaccination of children > 1 : not enough ● Fear : ↑ varicella among adolescents/adults and herpes zoster among the elderly ● Routine varicella vaccination not recommended for children > 1 ● Recommended, if no varicella history : - Vaccination within 3 days following exposure (adults & immunocompetent) - Health care workers - Contact with young children & immunodeficient people - Children organ recipientConseil Supérieur dHygiène Publique de France – Section Maladies Transmissibles – Avis relatif à la vaccination contre la varicelle 13 13(19 mars 2004)
“Ils sont fous ces américains” New driftsMailing infected clothes, saliva samples, infected lollipops... Danger for workers of mailing companies Risk of 20 years of imprisonment: under biohazard regulation (like anthrax)Looking for more dangerous diseases : Measles, mumps… 14