Measles In Children Do Children Need A Booster Vaccine After Having One For Measles When 18 Months Old ?

Do children need a booster vaccine after having one for measles when 18 months old ? - measles in children

my twins are not "MMR", as they were concerned about possible side effects, although three shots in a private school when she is 17 months, now 7, are always protected against measles?