“…The majority of the studies (93%) were from high-income countries [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 44 , 45 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ], and only two studies [ 43 , 46 ] were from low- and middle-income countries. In total, fourteen studies focused on the influenza vaccine [ 27 , 28 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 39 , 40 , 41 , 46 ], six studies on Tdap vaccine [ 42 , 45 , 47 , 48 , 49 , 52 ], eight studies on both Influenza and Tdap vaccines [ 29 , 38 ,…”