Varicella vaccine

Overview

The varicella vaccine is a shot that helps protect against chickenpox, a common and often mild childhood illness caused by the varicella-zoster virus. The vaccine teaches your immune system to recognize and fight the virus, so if you are exposed later, you either do not get chickenpox or get a very mild case.

Yes, the varicella vaccine is a routine childhood vaccine in many countries, including the UK (as part of the MMRV combination vaccine in some cases) and the US. Most children receive it as part of their regular immunisation schedule.

The vaccine is recommended for all children, and also for older children and adults who have never had chickenpox and have not been vaccinated. It is especially important for people who are at higher risk of complications from chickenpox, such as healthcare workers, teachers, and people with weakened immune systems.

Symptoms

Common symptoms

• Mild soreness, redness, or swelling at the injection site
• Low-grade fever
• A mild rash (sometimes a few chickenpox-like spots) that appears 5–26 days after vaccination

Symptoms in children

• Same as above; most children have no symptoms beyond mild injection site discomfort

Symptoms in older adults

• Older adults may have a slightly higher chance of mild fever or fatigue after vaccination, but serious reactions are rare

Causes

Main causes

• The varicella vaccine is given to prevent chickenpox, which is caused by the varicella-zoster virus. The vaccine itself contains a weakened form of the virus that triggers immunity without causing illness.

Risk factors

• Children aged 12 months and older who have not had chickenpox are at highest risk of infection, which is why vaccination is routine.
• Adolescents and adults who have never had chickenpox or the vaccine are at risk of more severe disease if they catch it.
• People with weakened immune systems (due to illness or medication) are at higher risk of complications from chickenpox and may need special vaccination advice.

When to see a doctor

See a doctor urgently if:

• If you or your child has any of the emergency symptoms listed above after vaccination.

Book a routine appointment if:

• If you have questions about whether the vaccine is right for you or your child.
• If you missed a dose of the vaccine and need to catch up.
• If you are pregnant, planning pregnancy, or have a medical condition that affects the immune system.

Diagnosis

There is no diagnosis needed for the varicella vaccine itself. Your healthcare provider will review your medical history and check if you have ever had chickenpox or the vaccine. A blood test can confirm if you are already immune, but this is not usually required.

Tests that may be done

• A simple blood test (varicella antibody test) can check if you have immunity from past infection or vaccination.
• No test is needed before routine vaccination.

What to expect at your appointment

Your healthcare provider will ask about any allergies or health conditions. The vaccine is given as an injection under the skin (subcutaneous). After the shot, you may be asked to wait 15 minutes to watch for any immediate allergic reaction. The provider will give you a vaccination record card.

Treatment

The varicella vaccine is a preventive measure, not a treatment for chickenpox. If you or your child has mild side effects from the vaccine, you can usually manage them at home.

Self-care at home

• Apply a cool, damp cloth to the injection site to reduce soreness.
• Give plenty of fluids and rest if there is a mild fever.
• Do not give aspirin to children or teenagers because of the risk of Reye’s syndrome.
• Use paracetamol or ibuprofen for fever or pain, following the recommended doses for age and weight.

Medical treatments

If a serious allergic reaction (anaphylaxis) occurs, it will be treated immediately with adrenaline and other emergency measures. Very rarely, people may develop a more pronounced rash or fever that needs evaluation by a healthcare provider, but most cases resolve without specific treatment.

When is surgery considered?

Not applicable. The vaccine does not require surgery.

Living with this condition

After receiving the varicella vaccine, you can generally go back to your usual activities right away, as long as you feel well. If you have a mild fever or sore arm, take it easy for a day.

Lifestyle tips

• Keep your vaccination record in a safe place so you know when the next dose is due.
• Follow the recommended immunisation schedule to ensure full protection.
• If you develop a rash after vaccination, avoid contact with pregnant women and people with weak immune systems until the rash clears, as the vaccine virus can rarely spread to others.

Diet and exercise

No special diet is needed. Eating well, staying hydrated, and getting regular exercise helps keep your immune system healthy. You can resume normal activity as soon as you feel up to it.

Mental health and emotional wellbeing

For most people, vaccination is a quick, simple step that brings peace of mind. Some people feel anxious about needles. If you or your child feels nervous, talk to your healthcare provider – they can offer ways to make the experience easier.

Prevention

Chickenpox is very effectively prevented by the varicella vaccine. The vaccine is the main way to protect yourself and your community from the disease.

Vaccines

The varicella vaccine is a live attenuated vaccine. It is sometimes given as a single shot or combined with the measles, mumps, and rubella vaccine (MMRV). The vaccine schedule and availability vary by country. Your healthcare provider can tell you which vaccine is used where you live.

Screening programmes

There is no routine screening required before vaccination. A blood test to check immunity is only done in certain cases, such as for healthcare workers or pregnant women.

Complications

If left untreated

• Not applicable – the vaccine is a preventive measure. However, if a person does not get vaccinated and catches chickenpox, possible complications include bacterial skin infections, pneumonia, inflammation of the brain (encephalitis), and, rarely, death.

Long-term outlook

The varicella vaccine is very safe and highly effective. After two doses, most people are protected from chickenpox for many years, likely for life. Even if a vaccinated person does get chickenpox, it is usually very mild with only a few spots and no fever. The vaccine has dramatically reduced the number of chickenpox cases, hospitalisations, and deaths worldwide.

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