About 15-30% of children who get scarlet fever are ages 5-15-years. It rarely affects children under the age of three. About 5-15% of adults will get the illness.
There is research showing that infections could be rising. According to a 2019 study, 2018 saw the highest number of reported scarlet fever cases in china in 20 years. It is similarly reemerging in other parts of the world.