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