Chickenpox (Varicella) Vaccine
This vaccine gives protection against chickenpox infection. Two doses of the vaccine give about 98% protection in children and about 75% protection in teenagers and adults. For those who are vaccinated but still get chickenpox, the symptoms will generally be milder.
In the UK the chickenpox vaccine is not currently part of the routine childhood schedule. It is recommended for those in close contact with people who are particularly at risk of complications from chickenpox. This includes:
- Healthcare workers of all kinds who are not immune to chickenpox
- Healthy family members and contacts of people without a fully-working immune system (for example, those with HIV, those without a spleen, people who have had an organ transplant, and those receiving chemotherapy treatment). As the chickenpox vaccine is a live vaccine (see Ingredients below), people without a fully-working immune system cannot receive the vaccine themselves.
The vaccine is also available for laboratory workers who are not immune to chickenpox and who may come into contact with the virus as part of their job.
The vaccine can be given to adults and children over the age of one year. Two doses are given, 4-8 weeks apart.
The vaccine contains a live, but weakened (attenuated) strain of the varicella-zoster (chickenpox) virus. The virus strain is grown in the laboratory using human cell-lines. See more information on human cell-lines.
There are two chickenpox vaccines recommended for use in the UK. Both may contain traces of neomycin, an antibiotic used in the production process. See more information on antibiotics in vaccines.
One of the chickenpox vaccines offered in the UK (Varivax) contains gelatin derived from pigs. See more information on gelatin in vaccines.
The other vaccine (Varilrix) may contain traces of human serum albumin, a very common protein found in human blood, used as a stabiliser.
The vaccine may also contain very small amounts of:
- salts based on sodium and potassium, used as acidity regulators
- sorbitol, mannitol, lactose or urea, safe organic compounds used as stabilisers
The chickenpox vaccines used in the UK do not contain the preservative thiomersal (mercury).
Very common side effects (affecting more than 1 in 10 people):
- reactions at the site of the injection, including redness, pain and swelling.
- high temperature (fever)
Common side effects (between 1 in 100 and 1 in 10 people):
- chickenpox-like rash (in up to 10% of adults and 5% of children)
- mild cold-like symptoms
- itching at the injection site
Less common side effects (between 1 in 1000 and 1 in 100 people):
- swollen glands, headache, sore throat, cough, or runny nose
- feeling sick or being sick
- a rash with blisters
- joint or muscle pain
- very high temperature
- drowsiness, tiredness, or feeling generally unwell
As with any vaccine, medicine or food, there is a very small chance of an immediate severe allergic reaction called anaphylaxis. Anaphylaxis is different from less severe allergic reactions because it causes life-threatening breathing and/or circulation problems. It is always serious but can be treated with adrenaline. In the UK between 1997 and 2003 there were a total of 130 reports of anaphylaxis following ALL immunisations, but all of these people survived. Around 117 million doses of vaccines were given in the UK during this period, making the overall rate around 1 in 900,000. Depending on the cause of the reaction, and following expert guidance, the person may be able to have vaccinations in the future.
Reactions listed under ‘possible side effects’ or ‘adverse events’ on vaccine product information sheets may not all be directly linked to the vaccine. See Vaccine side effects and adverse reactions for more information on why this is the case.
See more information on the monitoring of vaccine safety.
Because it is a live vaccine, there is a very small risk that someone who has been vaccinated could pass on the virus to someone who is not immune to chickenpox. This is usually only a risk if the person who has been vaccinated develops a chickenpox type rash at the injection site or elsewhere on the body.
The chickenpox vaccine should not be given to anyone with a weakened immune system. It should also not be given to pregnant women; women who have had the vaccine should avoid getting pregnant for three months after vaccination. However, studies have shown that the vaccine virus does not get passed to the baby through breast milk, so it is safe for breast-feeding women to be vaccinated.
A treatment called human varicella zoster immunoglobulin (VZIG) is given to people in risk groups who have been exposed to chickenpox. Immunoglobulins are special concentrated antibody preparations which provide immediate short-term protection against disease. VZIG can help to reduce the severity of chickenpox symptoms for some people in risk groups.
Published by Sarah Loving
Medical content reviewed by Professor Andrew Pollard
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Last updated 12 October 2015