no second dose was administered; This non-serious case was reported by a pharmacist via call center representative and described the occurrence of incomplete course of vaccination in a patient who received HAB (Twinrix) for prophylaxis. Previously administered products included Twinrix (received 1st dose of Twinrix vaccine on March 2024). On an unknown date, the patient did not receive Twinrix. On an unknown date, an unknown time after receiving Twinrix, the patient experienced incomplete course of vaccination (Verbatim: no second dose was administered). The outcome of the incomplete course of vaccination was unknown. This report is made by GSK without prejudice and does not imply any admission or liability for the incident or its consequences. Additional Information: GSK Receipt Date: 10-JAN-2025 The Healthcare professional reported on the day of reporting, 10th January 2025 that a patient received the first dose of Twinrix on March 2024 and had not received the second dose. The reporter was called to made clinical decision, no second dose was administered at the moment of the call yet. Till the time of reporting, the patient did not receive 2nd dose of Twinrix, which led to incomplete course of vaccination.