injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red; injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red; injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red; injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red; injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red; Initial information regarding this unsolicited valid non-serious case  was received from a consumer and transmitted to Sanofi on 27-Oct-2020.  This case involved a 5 years old male patient who experienced injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red (Vaccination site inflammation associated with Vaccination site erythema, Vaccination site pain, Vaccination site swelling and Vaccination site mass), while he received vaccine INFLUENZA QUADRIVAL A-B VACCINE [FLUZONE QUADRIVALENT].  Relevant medical history, past medical treatment, vaccination details and family history were not provided.  Concomitant medications included NA (sodium).  On 25-Oct-2020, the patient received a 0.5 mL dose of suspect INFLUENZA QUADRIVAL A-B VACCINE (lot number and expiry date not reported) via intramuscular route in the left arm for prophylactic vaccination.  On 26-Oct-2020, the patient was having an injection site reaction to the left arm described as the arm hurting, having a quarter sized red area the day after injection, then the area growing to a softball sized red area, the area now being hot to the touch, the arm being really sore, the arm being very swollen and red (Vaccination site inflammation associated with Vaccination site erythema, Vaccination site pain, Vaccination site swelling and Vaccination site mass), 1 day following the administration of INFLUENZA QUADRIVAL A-B VACCINE and the arm was not getting better.   The mother reported that the pharmacy was called; that she was advised to administer Benadryl; that the Benadryl did not help; that the consumer has not had a fever throughout the event; that the consumer has gotten flu shots in the past with no reaction.  Relevant laboratory test was not reported.  Final diagnosis was injection site reaction to the left arm described as the arm hurting, having a quarter sized red area, the area growing to a softball sized red area, now being hot to the touch, the arm being really sore, the arm being very swollen and red.   At the time of reporting, the patient had not recovered from the reported events.