Buzzy the Bee will be used on the patient during the 9-month vaccination procedure. Thanks to its cold wings and vibration, Buzzy reduces pain and helps distract the patient during the injection, thereby alleviating feelings of pain and fear. Buzzy will be placed 5 cm above the injection site; after a 15-second wait, the actual vaccination will be administered.

HST technique maneuvers will be applied to the 9-month-old infants in this group during vaccination. HST consists of a four-stage tapping sequence. The administering nurse will perform approximately 10 taps over a 5-second period using the palmar surface of the dominant hand's fingers to relax the leg muscles at the injection site (Stage 1). Following skin disinfection, the nurse will position the thumb and index finger of the non-dominant hand in a V-shape and perform 3 taps on the injection site using the palmar surface of those fingers (Stage 2). Simultaneously with the third tap, the nurse will insert the needle into the muscle at a 90-degree angle while continuing to tap the skin lightly with the palmar surface of the non-dominant hand's fingers (Stage 3). Once the medication has been fully administered, the nurse will perform 3 taps on the skin with the palmar surface of the non-dominant hand's fingers and withdraw the needle simultaneously with the final tap (Stage 4).

No intervention other than the administration of the vaccine by the nurse will be performed on the 9-month-old infant in this group. The 9-month-old infant will receive routine vaccination.