Patient then developed seizure disorder on 4/24/2021 after receiving his 2nd RECOMBIVAX HB; Caller reports the child has since been diagnosed with "CDKL5" which his HCP states is the reason for his seizures; his first RECOMBIVAX HB vaccination on 25-FEB-2021/ his 2nd RECOMBIVAX HB vaccine on 01-APR-2021; Circumcision; Caller reported her son developed gastrointestinal issues such as gas and constipation, constant crying and irritability immediately after receiving his first RECOMBIVAX HB vaccination; Caller reported her son developed gastrointestinal issues such as gas and constipation, constant crying and irritability immediately after receiving his first RECOMBIVAX HB vaccination; Irritability; constant crying; This spontaneous report was received from the patient's mother referring to male patient of unknown age. The concomitant medication was reported as none. There was not known drug allergies. The patient's concurrent conditions and medical history were not reported.  On 25-FEB-2021, the patient was vaccinated with the first dose of hepatitis b vaccine (recombinant) (RECOMBIVAX HB) 0.5 ml, intramuscularly (IM) (lot # S002770, expiration date: 04-NOV-2021) (strength and anatomical location were not reported) for routine vaccination. The patient developed gastrointestinal issues such as gas and constipation, constant crying and irritability immediately after receiving his first dose of hepatitis b vaccine (recombinant) (RECOMBIVAX HB). On 11-MAR-2021, the patient had circumcision. On 01-APR-2021, the patient was vaccinated with the second dose of hepatitis b vaccine (recombinant) (RECOMBIVAX HB) 0.5 ml, IM (lot # S002769, expiration date: 04-NOV-2021) (strength and anatomical location were not reported) for routine vaccination (inappropriate schedule of product administration).   On 03-MAY-2021, the patient developed seizure disorder after receiving his second dose of hepatitis b vaccine (recombinant) (RECOMBIVAX HB). The patient was hospitalized for the seizures from 04-MAY-201 until 07-MAY-2021. The patient was treated with "antivirals and antibiotics" (unknown names of medications) and levetiracetam (KEPPRA). Spinal tap, computerized tomography (CT), magnetic resonance imaging (MRI), labs and genetic testing were performed. The patient had since been diagnosed with "CDKL5" which his healthcare professional (HCP) stated was the reason for his seizures. The patient did not receive a third dose as the parent decided to stop vaccinating him.  The patient received the following vaccines on 18-MAY-2021: diphtheria (+) tetanus toxoids (+) acellular pertussis adsorbed (+) inactivated poliovirus (+) haemophilus b conjugate (tetanus toxoid conjugate) vaccine (PENTACEL), pneumococcal conjugate vaccine (PREVNAR 20) and rotavirus vaccine, live, oral, pentavalent (ROTETEQ) (lot # U007860, expiration date 14-JAN-2022 received 2ml orally). No new adverse events (AEs) were reported from these vaccines administered on 18-MAY-021. The outcome of CDKL5 and seizure was reported as not recovered. The outcome of gas and constipation, constant crying, irritability and circumcision was unknown.     The causality between the events and hepatitis b vaccine (recombinant) (RECOMBIVAX HB) was not reported.  The reporter considered that CDKL5 and seizure to be medically significant, disability and life threatening.  This is one of the two reports received from the same reporter (the other one is the patient's twin brother). ; Sender's Comments:  US-009507513-2203USA004828: