“…65 A similar rise in invasive, septic GAS disease was observed during the same time period in the UK, involving the same M types. 18,66 In contrast to what was seen in the US, no strains producing SpeA were identified from patients with severe or fatal acute infections, 18,66 suggesting that the increase in invasivity was related to an increase in the dominance of virulent M types rather than the presence or absence of speA. 18 SpeA has also been implicated in ARF, but (for example), while M5 and M18 are both strongly associated with ARF, 67 the M18 strain associated with ARF carries speA 39 while M5 does not.…”