Hospitalization; overdose; This serious case was reported by a consumer via other manufacturer and described the occurrence of hospitalization in a 6-month-old male patient who received DTPa-HBV-IPV (Pediarix) (batch number 7MM3Z) for prophylaxis.   Co-suspect products included MMR (MMR vaccine) for prophylaxis and VARICELLA ZOSTER VACCINE LIVE (VARICELLA VACCINE) for prophylaxis.   Previously administered products included Engerix-B (received on 7th June 2017 with batch number 9232L) and Pediarix (received 1st dose on 7th August 2017 with batch number 924Y3). Concomitant products included PEDIARIX.   On 18-DEC-2017, the patient received the 3rd dose of Pediarix. On an unknown date, the patient received MMR vaccine and VARICELLA VACCINE. On 18-DEC-2017, an unknown time after receiving Pediarix and not applicable after receiving MMR vaccine, the patient experienced extra dose administered (Verbatim: overdose). On an unknown date, the patient experienced hospitalization (Verbatim: Hospitalization) (serious criteria hospitalization). The outcome of the hospitalization was resolved (duration 10 days) and the outcome of the extra dose administered was unknown.   It was unknown if the reporter considered the hospitalization to be related to Pediarix and MMR vaccine.     It was unknown if the company considered the hospitalization to be related to Pediarix and MMR vaccine.   Additional Information: GSK receipt date: 28-SEP-2023 The patient received a dose of GSK's ENGERIX-B vaccine per CDC recommendations and received a 3 dose series vaccine, GSK's PEDIARIX. ENGERIX-B is a vaccine for Hepatitis B (FDA Approved 1987) PEDIARIX is a combination vaccine for DTaP + polio + Hep B (FDA Approved 2002) The CDC recommendation is to give 3 doses of Hep B, with medical facility use of PEDIRIX, patient's received 4 doses of Hepatitis B. The reporter may not be a physician but he/she know that 1 plus 3 is 4, making medical facility's protocol to use the PEDIARIX product an intentional overdose of Hepatitis B. This intentional overdose set off a chain reaction of events, including hospitalization of patient's 10 days after receiving the MMR and varicella vaccine. Although patient was given an extra dose of the Hepatitis B vaccine, you indicated medical facility providers have denied any connection between patient's symptoms and the vaccines,  The reporter stated that GSK last revised their PEDIARIX PI was in November 2022, 5 years after patient's received the PEDIARIX series.  The GSK package insert for this product specifically said there is limited safety data on children who receive 4 doses of Hep B.  The doctors at medical facility and GSK's PEDIARIX website both state that, per the CDC, it is safe to give 4 doses of Hepatitis B. Then why is this not reflected in the PEDIARIX PI?  Is GSK's PI not in compliance with the Code of Federal Regulations? OR was this a talking point everyone is supposed to take a face value and never question?  Why does medical facility have access to this magical data that the manufacturer of the product did not seem to have? It appeared that someone was lying. Who is it? The CDC? GSR? All of the above?  The grievance response reporter received from medical facility completely ignored my concerns about their partnership with the CDC's Vaccine Safety and my question about the PI.  The assistant physician-in-chief advised that you met with physician a specialist in Infectious Disease, about your concerns.  The physician reviewed the data and the CDC recommendations and explained there is no harm in administering an extra dose of the Hepatitis B vaccine. It was unknown if the reporter considered the hospitalization to be related to Varicella vaccine.  The patient received 3rd dose of Pediarix, which led to extra dose administered of hepatitis B antigen.