Varicella (chickenpox) vaccine - what you need to know

The varicella vaccine helps protect you from chickenpox. Chickenpox is caused by the varicella-zoster virus.

The vaccine contains a live but weakened form of the virus. It trains your immune system to recognize the virus without causing typical chickenpox in most people. Vaccination greatly lowers the chance of chickenpox and offers strong protection against severe illness.

The vaccine is given as an injection, usually in the upper arm or thigh. Depending on the product and local practice, it may be placed under the skin or into a muscle.

Some people receive a vaccine containing only varicella. Children may sometimes receive a combined measles, mumps, rubella, and varicella vaccine, known as MMRV.

The vaccine is given to prevent chickenpox. It may be offered as part of routine childhood vaccination or as catch-up vaccination for an adolescent or adult who does not have evidence of immunity.

Vaccination may be especially important if you could be exposed at work, while travelling, or through close contact with children. It also reduces the chance that you will pass the virus to someone who could become seriously ill.

The vaccine may be recommended soon after exposure to chickenpox. When given promptly, it may prevent the infection or make it milder. It is not a treatment for chickenpox that has already developed.

The recommended number and timing of doses are based on your age, previous vaccinations, health, and exposure history.

The vaccine is generally suitable for children, adolescents, and adults who do not have evidence of immunity to chickenpox. Evidence may include documented vaccination, laboratory evidence of immunity, or a history that meets local public health criteria.

Because this is a live vaccine, it is not right for everyone. It is usually avoided during pregnancy and in people with severe immune suppression. This can include some people receiving cancer treatment, transplant medicines, or other treatments that strongly suppress the immune system. People with certain immune conditions may still be eligible after specialist assessment.

You should not receive another dose if you had a life-threatening allergic reaction to an earlier dose or to a vaccine ingredient. Varicella vaccines may contain ingredients such as gelatin or traces of neomycin, depending on the product.

Vaccination may need to be delayed if you:

• Have a moderate or severe current illness
• Recently received a blood transfusion, plasma, or immune globulin
• Take antiviral medicine active against varicella-zoster virus
• Take medicines that suppress your immune system
• Are pregnant or may be pregnant

A mild illness, such as a minor cold, does not always require delay. Breastfeeding is not generally a reason to avoid varicella vaccination.

Tell the vaccination team if you take aspirin or another salicylate medicine. They can review the product-specific precautions and whether your treatment can safely continue.

Follow the treating facility’s own instructions first, because its preparation and screening process takes priority.

Bring your vaccination record if you have one. Be ready to discuss previous chickenpox infection, earlier vaccine doses, allergies, pregnancy, recent blood products, and medicines that affect your immune system.

You do not usually need to fast. You can eat, drink, and take most regular medicines as normal unless the facility gives you different instructions.

Wear clothing that makes your upper arm easy to reach. If injections make you faint or feel light-headed, tell the person giving the vaccine. You may be vaccinated while sitting or lying down.

Do not stop a prescribed medicine without instructions from the clinician responsible for it.

Before the injection, a healthcare professional checks your identity, vaccination history, allergies, and reasons the vaccine might need to be delayed. You can ask questions before agreeing to proceed.

The skin may be cleaned. A small needle is then used to inject the vaccine into the upper arm or thigh. The injection itself takes only a few seconds.

You may be asked to remain at the clinic briefly afterward. This allows staff to help if you feel faint or have an immediate allergic reaction.

No anaesthetic or sedation is needed. You remain awake throughout.

Your arm may feel sore, tender, or slightly swollen. A cool compress can help. Ask your healthcare team which pain medicine is suitable if you need it.

You can eat and drink normally after vaccination.

Most people can return to their usual activities immediately. If you feel feverish or tired, rest and avoid strenuous activity until you feel better.

There is no routine driving restriction. Do not drive if you feel faint, dizzy, or unwell.

You can usually return to work or school the same day. A small number of people develop a mild chickenpox-like rash after vaccination. If this happens, contact your healthcare team for advice, particularly if you have close contact with a pregnant person, newborn, or someone with severe immune suppression.

Common effects include pain, redness, or swelling where the injection was given. Some people develop a fever or a small number of chickenpox-like spots.

Fainting can happen around any injection, especially in adolescents. Sitting or lying down during vaccination and remaining seated afterward can reduce the chance of injury.

Less common complications include a seizure associated with fever or a temporary reduction in certain blood cells. Serious nervous-system or lung complications have been reported but are uncommon.

A severe allergic reaction can occur after any vaccine. Vaccination facilities should have equipment and trained staff available to treat it.

Because the vaccine contains a weakened live virus, transmission of the vaccine virus is possible but very unusual. It has mainly been reported when the vaccinated person developed a rash.

The vaccine cannot prevent every case. If chickenpox occurs after vaccination, it is often milder, but you can still pass the infection to other people.

The vaccine begins building protection over the following weeks. There is no immediate result to see, and routine blood testing after vaccination is not usually needed.

Before leaving, confirm whether you need another dose and when it should be given. Keep the written or electronic vaccination record, including the product, date, and clinic.

Contact the clinic routinely if you lose your record, are unsure whether another dose is due, or later learn that you were pregnant or severely immune-suppressed at the time of vaccination. These situations need individual review but are not automatically emergencies.

There is no non-vaccine option that provides the same kind of long-term active protection.

You can choose not to be vaccinated. This avoids vaccine side effects but leaves you at risk of chickenpox and its complications. Deliberate exposure to chickenpox is not a safe alternative because the severity of infection cannot be predicted.

Avoiding close contact with an infected person may lower exposure, but it is unreliable. Chickenpox can spread before the rash appears, and the virus can travel through the air.

After exposure, certain people who cannot receive the vaccine may be offered varicella-zoster immune globulin. This provides ready-made antibodies for temporary protection. It is reserved for specific higher-risk situations and does not replace routine vaccination.

A combined MMRV vaccine may be an option for some children. It reduces the number of separate injections but has different age restrictions and side-effect considerations. It is not generally used for adults.

Contact your healthcare team for advice if you develop:

• A high or persistent fever
• A spreading or worsening chickenpox-like rash
• Unusual bruising or bleeding
• Symptoms that are severe, unexpected, or not improving
• A rash when you have close contact with someone at high risk

Seek emergency help immediately for trouble breathing, swelling of the face or throat, widespread hives, severe weakness, collapse, or other signs of a serious allergic reaction.

A seizure, severe confusion, difficulty waking, or major breathing difficulty also needs emergency assessment.

Routine arm soreness, mild tiredness, or a low fever can usually be monitored at home. If you are uncertain, contact the clinic that gave the vaccine.

Will I be asleep?

No. The vaccine is a quick injection and does not require sedation or anaesthesia.

Can I drive home?

Yes, in most cases. Do not drive if you feel faint, dizzy, or unwell after the injection.

How painful is it?

You may feel a brief sting. Your arm can remain sore for a day or two, but severe pain is not expected.

When will I know it worked?

Protection develops over several weeks. There is usually no follow-up test. Your vaccination record shows that the dose was given, but no vaccine offers complete protection.

Can the vaccine give me chickenpox?

It does not usually cause typical chickenpox. A small number of people develop a mild rash with a few spots because the vaccine contains weakened live virus.

Can I have it if I am pregnant?

Varicella vaccine is not given during pregnancy. If you may be pregnant, tell the vaccination team before the injection. People are generally advised to avoid pregnancy for one month after each dose.