PIGG and scarlet fever: You Y collected 2484 strains of GAS during 2011–2018 and found that the prevalent emm types of GAS causing scarlet fever shifted for 8 years in Beijing since 2012, the frequency of emm12 S pyogenes started to decline from 2011, whereas emm1 started to increase and then exceeded emm12 in 2013 and 2014.