This page provides a brief summary of the disease and the vaccine that is available to prevent it. Links to more detailed information are provided at the bottom of the page.
What is chickenpox (varicella)?
Chickenpox is a disease is caused by the varicella-zoster virus. The disease is most common in childhood but chickenpox can be more severe in adults who have not been vaccinated.
How do people get chickenpox?
Chickenpox is spread by close contact with an infected person. The disease is very contagious and will spread to 9 out of ten unvaccinated close contacts.
What are the symptoms of chickenpox?
The virus infection causes an itchy rash which starts with red spots that typically develop into small fluid filled blisters (vesicles). After a few days these crust over before healing The rash usually is first seen on the head and neck and spreads to the rest of the body. There can be from a few to several hundred vesicles on the skin. A person with Chickenpox may feel sick, tired and have a fever (temperature of 38°C or higher). The vesicles are not painful unless they become infected.
What are the complications of chickenpox?
- Infection of the rash,
- skin scarring (especially if the rash is infected)
- encephalitis (inflammation of the brain),
- pneumonia,
- glomerulonephritis (kidney damage)
- myocarditis (inflammation of the heart)
- hepatitis (inflammation of the liver)
- coagulopathy (bleeding disorder) 1 in 6000 will get a blood clotting problem.
- In 2023, there were 170 hospitalisations after chickenpox infections and complications arising from chickenpox. Most people who were hopsitalised were children under 10 years of age.
Can you prevent chickenpox?
Yes. The chickenpox (varicella) vaccine protects against chickenpox (varicella). The vaccine is a live attenuated vaccine. This means that it contains a weakened form of the varicella zoster virus.
Who will be offered the chickenpox (varicella) vaccine?
Children born on or after 1st October 2024 will be offered the varicella vaccine when they are aged 12 months so the vaccine will be available from 1st October 2025. The vaccine will be available free through the GP practice.
The vaccine will not be available free for children born before 1st October 2024. If parents or guardians of children born before 1st October 2024 want them to get the chickenpox vaccine, they will have to pay for it privately.
Is the chickenpox (varicella) vaccine a new vaccine?
In the United States the chickenpox (varicella) has been available since 1995 for anyone aged 12 months or older. Germany was the first European country to introduce universal Varicella (Chickenpox) vaccination in 2004. The chickenpox vaccine has been available in Ireland for many years, but not as part of the childhood immunisation programme, so parents/guardians had to pay for it if they wanted their child vaccinated.
How many doses of chickenpox (varicella) vaccine are needed in the routine vaccination schedule?
The recommended schedule is two doses of chickenpox (varicella) vaccine. The first dose is recommended at 12 months of age. The second dose of chickenpox (varicella) vaccine will be given combined with the MMR vaccine (MMRV) when children born on or after 1 October 2024 are aged 4-5 years, in junior infants in primary school.
Who should not get the chickenpox (varicella) vaccine?
The varicella (chickenpox) vaccine is safe for most people.
However, your child should not get the vaccine if:
- they have had a severe allergic reaction (anaphylaxis) to a previous varicella vaccine or any part of the vaccine including gelatin or a severe allergic reaction to an antibiotic called neomycin.
- If a child’s immune system is severely weakened by illness or treatment (e.g. chemotherapy), they will not be able to have the varicella vaccine.
You should delay getting the vaccine if your child:
- is ill with a fever
- has recently received a blood transfusion or blood products
What to expect after getting chicken pox (varicella) vaccine?
After getting the vaccine, your child may have discomfort, redness or swelling around the area where the injection was given. They may be irritable and have a fever.
If this happens you can give them liquid infant paracetamol or infant ibuprofen. You should also give them plenty to drink. Make sure they are not too warm and that their clothes are not rubbing against the injection area.
Salicylate (e.g. aspirin)-containing medicines should be avoided for six weeks after vaccination in children under 16 years.
Children usually recover from these minor side effects within a day or two
Of the children who are immunised:
- 1 in 10 will have soreness redness and swelling where the injection was given
- 1 in 10 will have a fever or irritability
- 3 in 100 will develop a mild rash after 5-26 days
- Serious side effects are very rare.
Can my child get a rash after the chicken pox (varicella) vaccine?
Yes. About 3 in 100 children get a rash after getting the chickenpox vaccine. The rash can happen 5 – 26 days after getting the vaccine.
What does the rash look like?
There may be a few red spots. These spots can be flat or raised. Some spots may look a bit like chickenpox. The spots are usually where the injection was given, but they may be on other parts of the body.
Does the rash need treatment?
No. The rash does not make your child feel sick, and it goes away on its own without treatment.
What precautions should I take if my child has a rash after chickenpox (varicella) vaccine?
As a precaution, children who develop a rash after getting the vaccine should not have contact with pregnant women who have never had chickenpox and newborn babies in the first week of life, if their mothers have never had chickenpox.
Children who develop a rash after the vaccine should also have no contact with people with a very weak immune system – for example, people on chemotherapy for cancer. This is because there is an extremely small risk of getting a mild form of chickenpox from someone who has a rash after the chickenpox vaccine.
This advice is only until the rash has gone, or the small spots have dried up (usually about five days).
The risk of anyone getting an infection from a rash after the chickenpox vaccine is extremely small. In the USA, they gave 56 million doses of varicella (chickenpox) vaccines over 10 years and only six people got a mild chickenpox infection spread from someone who had a rash after the vaccine. This means that if your child develops a rash after the vaccine, the risk of them infecting someone else is just 1 in about 9 million.
What should I do if my child has a rash after the chicken pox (varicella) vaccine and they can’t avoid contact with people at risk?
Those at risk are pregnant women who never had chickenpox, newborn babies whose mothers never had chickenpox, and those with weakened immune systems. If your child can’t avoid being in contact with these people, talk to your GP or General Practice Nurse.
Remember – the risk of anyone getting chickenpox infection from a person with a rash after the chickenpox vaccine is extremely small (about 1 in 9 million).
Can a child whose mother is pregnant but has not had chickenpox have the chickenpox (varicella) vaccine?
Yes. It is very important that a child living with a pregnant woman who has never had chickenpox, or a newborn baby whose mothers never had chickenpox is vaccinated. Vaccination of the child helps protect the pregnant woman or baby from chickenpox (varicella) infection, and its serious complications.
Can a child who is living with someone with a very weak immune system have the chickenpox (varicella) vaccine?
Yes. It is very important that a child living with someone with a very weak immune system (for example someone getting treatment for cancer) has the chickenpox vaccine. Vaccination of the child helps to protect the person with the weak immune system from chickenpox (varicella) infection and its serious complications.
How does chickenpox (varicella) vaccine work?
The vaccine works by stimulating the immune system to develop protection against the chickenpox virus without giving your child chickenpox diseases.
How effective is chickenpox (varicella) vaccine?
The full course of chickenpox (varicella) vaccine offers very good protection against chickenpox (varicella) infection for up to 98% of children vaccinated.
For more information
- Further information on immunisation is available from your G.P., public health nurse, or local health office.
- Click here for additional resource matierials such as: Your Child’s Immunisations A guide for parents
This page was updated on 1 October 2024
