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:
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 strain of the varicella-zoster (chickenpox) virus which has been weakened (attenuated), so that it stimulates the immune system but does not cause disease in healthy people. It should not be given to people who are clinically immunosuppressed (either due to drug treatment or underlying illness). This is because the vaccine strain could replicate too much and cause a serious infection. This includes babies whose mothers have had immunosuppressive treatment while they were pregnant or breastfeeding. For more information see the MHRA's Drug Safety Update (April 2016) .
In some countries all children are offered either the chickenpox (varicella) vaccine or MMRV vaccine (a combined measles, mumps, rubella and varicella vaccine). MMRV vaccine is not currently available in the UK, but the UK Government is considering whether to introduce varicella vaccine in future. See ‘More information about the vaccine’ below.
The virus strain used in the vaccine 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:
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):
Common side effects (between 1 in 100 and 1 in 10 people):
Less common side effects (between 1 in 1000 and 1 in 100 people):
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.
The chickenpox vaccine currently available in the UK is a single vaccine. However, several countries use the MMRV vaccine, which combines the MMR (measles, mumps and rubella) vaccine with a varicella (chickenpox) vaccine. This vaccine is given routinely in the USA, Germany and Australia. For children aged two and younger, studies have shown that more of them develop fever after the MMRV vaccine, compared with giving the MMR vaccine and the chickenpox vaccine separately on the same day. In particular there is an increased risk of febrile convulsions (fits). These occur 7 to 10 days after MMRV vaccination.
The Joint Committee on Vaccination and Immunisation (JCVI) , which advises the UK Government, has so far advised that it would not be cost effective to introduce the chickenpox vaccine or the MMRV vaccine into the routine UK schedule. As long as most children received the vaccine it would be very effective in reducing cases of severe chickenpox disease, but it is thought that cases of shingles in older people would increase. Shingles is very expensive for the NHS to treat. It is believed that many adults in the UK get their immunity to chickenpox boosted by coming into contact with children who have the disease. Several studies have shown that this may make adults less likely to develop shingles as they get older. If a chickenpox vaccine was introduced but not taken up by many people, there might be more adults who did not receive the vaccine or have “wild” chickenpox in childhood. They would then be at an increased risk of severe chickenpox infection as adults.
However, the JCVI is currently reviewing data from other countries where the vaccine has been in routine use over the past decade or two. It will use this to see what impact the chickenpox or MMRV vaccine is having on chickenpox and on shingles, and then advise the Government on whether there should be any change to the current advice on chickenpox vaccine. For more information see the JCVI minutes from October 2009 .