Varicella vaccine

The vaccine gives protection against chickenpox and its secondary diseases, which are infected blisters and an extensive bacterial skin infection, encephalitis (inflammation of the brain) and pneumonia.
Vaccine-preventable diseases

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To whom is the varicella vaccine administered?

In the national vaccination programme, a free varicella vaccine is offered to all children born on or after 1 January 2006 who have not had chickenpox.

If a child has had a very mild form of chickenpox when under 12 months old, they may get it again. This is why the current recommendation is to also vaccinate these children.

The varicella vaccinations in the national vaccination programme are administered in connection with age-specific health examinations at their child health clinic and school.

The varicella vaccines of the national programme may also be used for varicella vaccinations referred to in section 48 of the Communicable Diseases Act. Only a few per cent of the adult population have not had chickenpox, which is why there is little need for these vaccinations. Varicella vaccines should not be ordered unnecessarily, for example by student or occupational healthcare services.

Which vaccine is used and what does it contain?

The product used in the vaccination programme is called Varivax. 

The varicella vaccine contains

  • live attenuated varicella viruses
  • sucrose, hydrolysed gelatine, urea, salts and monosodium L-glutamate as excipients
  • neomycin as residual components only
  • the vaccine contains no adjuvants.

Dosage and schedule

The vaccine dose is 0.5 ml.

The primary vaccination series consists of two doses. 

All children aged between 1.5 to 11 years are offered one dose of the vaccine in connection with the age-specific health examination at their child health clinic or school.

  • Children who have received the first dose when aged under 6 years are offered a booster at the child health clinic when they turn 6. In this case, the MMRV vaccine is used.
    MMRV vaccine
  • Children who received the first dose at the age of 6 to 11 years are offered a booster at the age of 12. This vaccination is administered by the school health care services.
  • Children aged 13 or over are administered two doses with an interval of 3 months between the doses.

The minimum interval between two varicella vaccine doses is 3 months. Varivax can be used to continue a vaccination series started with some other product.

What are the benefits of the varicella vaccine?

The vaccination gives protection against chickenpox, the symptoms of which are fever and a very itchy rash with blisters. The varicella virus causes a systemic viral infection. Among other things, the virus multiplies in the skin blisters, the liver and the spleen.

The vaccination gives protection against the secondary diseases of chickenpox, which include:

  • infected blisters and an extensive bacterial skin infection. Vaccinations also help prevent hospitalisation and scarring caused by infected blisters.
  • encephalitis (inflammation of the brain). Of those who contract chickenpox in adulthood, 1 out of 14,000 patients develop severe encephalitis.
  • pneumonia.

If a woman contracts chickenpox in early pregnancy, the foetus has a risk of developing birth defects, including microcephaly (smaller than normal head), malformations of the limbs and blindness.

Approx. one out of three of those whose who have had chickenpox contract shingles, which is a painful condition. The varicella vaccine reduces the incidence of shingles by 70% to 80%.

In the United States, two vaccine doses have been found to give 93% protection against all chickenpox infections, and almost 100% protection against severe cases.

Vaccinations have almost eradicated chickenpox infections in the United States and reduced the need for hospitalisations significantly.

What are the potential adverse effects of the varicella vaccine?

Most healthy recipients develop no symptoms.

One out of five experience local symptoms at the injection site, including pain, redness or swelling.

Less than 5% develop blisters typical of chickenpox close to the injection site or in other areas of the body. Usually, they only have two to five blisters.

Generalised symptoms are rare. Approx. 15% of those who are vaccinated develop a fever.

The local reactions and generalised symptoms may be treated with fever and pain medications.

Chickenpox is associated with a significant risk of encephalitis (inflammation of the brain), whereas severe neurological complications are extremely rare in those who have been vaccinated. Convulsions are usually observed in connection with fever caused by the vaccination. Febrile convulsions are very rare. The risk of convulsions associated with chickenpox is considerably higher.

If a more extended chickenpox-like rash occurs within 14 days of the vaccination being administered, it is most likely caused by a wild virus rather than associated with the vaccination. 

If a rash occurs within 15 to 42 days, it may have been caused by the virus in the vaccine. A chickenpox-like rash that occurs more than six weeks later probably means that the vaccine has not taken effect and the child has contracted chickenpox.

Shingles is extremely rare in healthy vaccine recipients

The virus in the vaccine may cause a latent infection and be activated as shingles, similarly to the ordinary chickenpox virus. It is not known, however, if the virus contained in the vaccine remains in the systems of all vaccine recipients. 

Shingles is extremely rare in healthy vaccine recipients. It seems to be more common in those who develop a blistering rash following the vaccination.

Vaccine virus rarely spreads from person to person

It is possible, but very rare, that the virus contained in the vaccine spreads to another person susceptible to chickenpox. The infection may be caused by a burst blister. 

Out of 55 million vaccine doses administered in the United States, only five cases were reported in which the vaccine virus had spread from a recipient with a normal immune system.

Vaccine reactions in immunodeficient recipients

One half of children with leukaemia have a reaction to the vaccine. Approx. one out of five develop more than 50 blisters. Persons in other at-risk groups are less likely to have a reaction.

Children with leukaemia who have been vaccinated are less likely to have shingles than those who have had chickenpox. If the child does not develop a skin reaction after vaccination, it is also unlikely that they will get shingles.

An immunodeficient varicella vaccine recipient should contact a physician if they develop a chickenpox-like rash. Acyclovir treatment is recommended to immunodeficient patients if they have more than 50 blisters.

History of the varicella vaccine in the national vaccination programme

The varicella vaccine was added to the national vaccination programme in autumn 2017. Children born on or after 1 January 2006 are entitled to the vaccinations. 

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