Grant: CIHR Fellowship

Many parents and vaccine providers are worried about the number of needles that children receive when they go for their immunizations. Putting multiple vaccines into one needle is one way to decrease the number of needles a child needs. In 2010, Alberta introduced a vaccine that combined the chickenpox (also called varicella) vaccine with another vaccine that includes measles, mumps, and rubella. This combination vaccine, called 'MMR-V', is now being used in 9 provinces and territories in Canada. One less needle is a good idea for people who think there are too many needles, and it may increase the number of people agreeing to immunize their child. However, studies have found that a similar vaccine in the USA resulted in more 'febrile seizures' (seizures related to high fever) after the vaccine. Although febrile seizures do not usually result in any long term harm, they can be extremely distressing to parents. Some parents may also refuse the MMR-V vaccine because they believe combination vaccines in general are unsafe, or because they don't want their child to get one part of the vaccine, even though they don't mind the other part. The purpose of this study is to determine whether introducing the MMR-V combination vaccine in Alberta increased the number of children getting immunized or whether parents are refusing the vaccine or choosing the separate vaccines. We also want to know whether there has been any change in the number of febrile seizures in children receiving the vaccine, compared to children that received the separate vaccines before MMR-V was introduced. We will conduct this study by looking at information in provincial databases that keep track of immunizations, as well as doctor, emergency department, and hospital records. This research can help us decide whether the MMR-V vaccine is safe to use, whether parents prefer these kinds of vaccines, and whether using more combination vaccines in the future would be a good idea.