At 12 months to 15 months, your child will receive a single shot immunizing her against mumps, measles and rubella. Though these diseases are best known for the rashes (measles and rubella) and glandular swelling (mumps) they produce, each may also cause serious medical complications. Immunizations against these diseases rarely cause any serious side effects, but your child may experience the following reactions, beginning seven to 10 days following the injection:
Very rarely, children will have slight swelling over the jaw, as if they had mild mumps from the mumps vaccine. The rubella part of the vaccine sometimes causes joint pains and swelling or, very rarely, an inflammation of the nerves of the arms or legs.
Because not all children are immune to these diseases after one vaccination and in order to give additional protection, each child should receive a second MMR vaccine. This booster dose is recommended to be given at 4 to 6 years of age. If this dose was not given earlier, it should be given at 11 to 12 years of age. In recent years physicians have become particularly concerned about outbreaks of measles, with more than half of the affected children having received only one MMR inoculation.
Because this vaccine contains a small amount of egg protein, there are differing opinions about whether or not your healthy child should receive these vaccines, if she is highly allergic to eggs. However, your pediatrician may want to consult with an allergist or immunologist, who will advise you and your child's doctor before a decision is made concerning the use of the vaccine. Also, if your child is taking any medication that interferes with the immune system, or her immune system is weakened for any reason, she should not be given the MMR.