ProQuad

ProQuad is a vaccine against measles, mumps, rubella, and varicella (chickenpox). ProQuad is available as a powder and solvent that are made up into a suspension for injection. The active substances are attenuated (weakened) viruses for the diseases.

ProQuad is given to children from 12 months of age to help protect them against the four diseases: measles, mumps, rubella, and chickenpox. ProQuad may also be given to children from nine months of age in certain situations, for example as part of a national vaccination programme, during an outbreak or for travel to a region where measles is common.

The vaccine can only be obtained with a prescription.

ProQuad is used according to official recommendations, including the number of doses and the interval between them.

For children above 12 months of age, one ProQuad injection is sufficient to provide optimal protection against measles, mumps and rubella. To protect against chickenpox, a second injection is needed, given one to three months after the first one; this can be done either by giving a second dose of ProQuad, or by giving a dose of another vaccine that only protects against chickenpox.

Children between nine and 12 months of age should receive a second dose at least three months after the first dose to ensure that they are adequately protected against measles and chickenpox.

The vaccine is injected into a muscle or under the skin, preferably in the thigh in younger children and in the shoulder area in older children and adults. It is only given under the skin in patients with low levels of platelets in the blood or other bleeding disorders, as they may experience bleeding if the vaccine is injected into a muscle.

ProQuad is a vaccine. Vaccines work by ‘teaching’ the immune system (the body’s natural defences) how to defend itself against a disease. ProQuad contains weakened forms of the viruses that cause measles, mumps, rubella and chickenpox. When a person is given the vaccine, the immune system recognises the weakened viruses as ‘foreign’ and makes defences against them. In the future, the immune system will be able to respond more quickly when it is exposed to the viruses again. This will help to protect against the diseases caused by these viruses.

Because ProQuad contains well known weakened viruses, which are already used in other vaccines, the company presented data from vaccines that are already on the market. The main studies were carried out to look at the ability of one or two doses of the vaccine to trigger an immune response in 5,446 healthy children (aged 12 to 23 months). ProQuad was compared with its ‘component vaccines’, a triple vaccine against mumps, measles and rubella, and a vaccine against chickenpox. Another study also looked at the responses one year after vaccination in 2,108 children.

A study has also been carried out with ProQuad in 1,620 children who received the first dose at 9, 11 and 12 months of age, and the second dose three months later. This study looked at the ability of the vaccine to trigger immune responses in these age groups.

The response rates in children above 12 months of age (measuring how the immune system had responded to the viruses) were: 98% for measles, 96% to 99% for mumps, 96% for rubella and 91% for chickenpox. After the second dose, the rates were around 99% for measles, 100% for mumps, 98% for rubella, and 99% for chickenpox.

The study in children from nine to 12 months of age showed that, after two doses of ProQuad, the immune response against mumps, rubella and chickenpox in children who received the first dose at nine months of age was comparable with those who received the first dose at 12 months of age. However, children who received the first dose at nine months of age had a lower immune response against measles.

The most common side effect with ProQuad (seen in more than 1 patient in 10) are fever, and pain and erythema (redness) at the site of injection. For the full list of all side effects reported with ProQuad, see the package leaflet.

ProQuad must not be used in children who are hypersensitive (allergic) to any chickenpox vaccine or measles, mumps or rubella vaccine, to any of the other ingredients, or to neomycin. It must not be used in children who have severely weakened immune systems. It must also not be used in a pregnant woman. For the full list of restrictions, see the package leaflet.

The CHMP decided that ProQuad’s benefits are greater than its risks and recommended that it be given marketing authorisation for use in children above 12 months of age, noting that a second vaccination against chickenpox should be given for full protection against the disease.

The Committee also recommended that the vaccine be authorised in children from nine to 12 months of age only in certain situations, for example as part of a national vaccination programme, during an outbreak or for travel to a region where measles is common.

The European Commission granted a marketing authorisation valid throughout the European Union for ProQuad on 6 April 2006.

For more information about treatment with ProQuad, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.