“…20 of the 55 studies included population-based control groups [ 10 , 11 , 19 , 20 , 23 , 24 , 26 , 29 , 33 , 35 , 36 , 38 , 39 , 46 , 47 , 53 , 60 – 63 , 65 ]. 18 (33%) recruited from a mix of previously hospitalised and non-hospitalised [ 11 , 23 , 26 , 31 , 32 , 35 , 36 , 40 , 41 , 48 , 49 , 51 , 53 , 58 , 61 , 65 , 67 , 71 ], 27 (49%) recruited from non-hospitalised CYP [ 10 , 12 , 19 , 20 , 24 , 27 – 29 , 33 , 37 , 38 , 45 – 47 , 52 , 54 – 57 , 59 , 60 , 62 , 63 ,…”