The British government said last week it was drawing up protocols to ease shortages of penicillin drugs used to treat strep A infections, allowing pharmacists to prescribe substitutes when stocks run low.
According to the UKHSA, there have been 27,486 cases of scarlet fever from 12 September to 18 December.
That compared with 3,287 cases at the same point in the year during the previous relatively high season in 2017 to 2018, the agency said, although cases began to rise at a different time in that season.