Varicella vaccine should be introduced into the UK immunisation programme immediately
Andrew J Pollard
Varicella
• The vaccine programme is about improving child health
• Burden of disease
• Mortality
• Complications
Chickenpox Epidemiology
• 90% infected by 18 years of age• 670,000 cases per year in England & Wales• 51% of cases <5 years of age• 84% of cases <15 (~600,000)• 14% in 15-44 year age group = 100,000 cases
Extrapolation from German data
• Varicella-related hospitalization 14.1/100,000 children (95% CI: 9.7–18.6),
• 27 hospitalizations per 10,000 varicella cases.
• 1809 children hospitalised per year
• 6 deaths per year
Transmission
• 90% of non-immune household contacts become infected
• Any face to face contact• 15 minutes in the same room• Any ward exposure• Options
– VZIG– Active vaccination– Anti-virals
Complications
• BPSU Nov 2002-Nov 2003– 112 cases
• 30 pneumonia• 30 bacteraemia/septic shock• 26 encephalitis• 25 ataxia• 14 toxic shock• 7 necrotising fasciitis• 5 purpura fulminans• 5 fulminant varicella• 3 neonatal varicella• 29 admitted to icu• 6 deaths
Cameron at al 2007
Complications
• Blood• 69% Group A Strep• 12% Staph aureus
• Skin• 36% Group A Strep• 64% Staph aureus
Cameron at al 2007
Pregnancy
• 5-10% childbearing age are susceptible
• Tropical areas may be as high as 20-40%
• Infection in first 20 weeks = 1-2 % congenital varicella
Vaccine Efficacy
• 5 years = 90%
• 97% effective against severe and moderately severe disease
• Breakthrough cases 5-7% over 5 years
• 2nd dose of VZV
• 5-107 spots
• Mixture of maculopapular and vesicles
Shinefield 2002, Vazquez 2001, Chaves 2007
Adverse events
• Varicella rash – 4-6%– Day 2-33– Number of spots 1-100– Duration of spots 1-16
White 1991, Lau 2002
Oxman 2005ZOSTER
Impact of varicella vaccine
Decline in mortality in
USA
Nguyen 2005
Vaccine introduced in 1995