Children with chickenpox are advised not to attend early childhood services, school or public places for at least one week from the appearance of the rash until all the blisters are dry and crusted. Adults are advised not to attend work or public places for the same period of time.
High risk contacts should also be excluded from early childhood services and school during the duration of an outbreak.
Varilrix® and Varivax® are the two chickenpox vaccine brands available for private purchase through your nurse or doctor. Both contain live weakened Oka strain varicella zoster virus. The combination measles, mumps, rubella and chickenpox vaccine is not available in New Zealand at this time.
The herpes zoster vaccine Zostavax® is licensed for adults 50 years of age and over for the prevention of shingles.
Chickenpox vaccine can be given from nine months of age ideally before but also if necessary after exposure to the disease. Studies have shown that giving the vaccine to children 12 years or younger within 72-96 hours of exposure to chickenpox can prevent the disease developing or reduce the severity of the disease. The vaccine can also be given to older children and adults after exposure to chickenpox. However, a single dose after exposure in this age group may not prevent or reduce the severity of disease. Receiving the vaccine after exposure to the disease will not make the disease more severe at any age.
All new born newborn infants exposed to chickenpox around the time of delivery, hospitalised infants born before 28 weeks of pregnancy or with a birth weight less than 1000 grams, and children and adults with weakened immune systems and no reliable history of chickenpox should receive zoster immunoglobulin, a human blood product that provides protection against the disease, as soon as possible after and within 96 hours of exposure to the disease.
Pregnant women with no reliable history of chickenpox should have an urgent blood test to check for immunity after exposure to chickenpox. If the blood test suggests no immunity against chickenpox, they can receive zoster immunoglobulin within 96 hours of exposure, or wait for the onset of symptoms and begin antiviral medicine immediately.
Contact can be defined as:
- Household contact – individuals living in the same house are very likely to be infected if susceptible.
- Play mate contact – defined as more than one hour of play indoors with an infected individual.
- Newborn infant contact – occurs when the mother of a newborn infant develops chicken pox, but not shingles, from one week before to one week after delivery.
Post-exposure prophylaxis with Zoster Immune Globulin (ZIG)
The recommended ZIG concentration is 100 U/mL with the volume of dose administered determined by the age of the recipient:
- Adults - 6mL
- Children aged 6-12 years - 4mL
- Children aged 0-5 years - 2mL
Human normal IG is indicated when ZIG is unavailable