Received May 6, 2026
| Type | Name | Manufacturer | Dose | Lot | Route / Site |
|---|---|---|---|---|---|
| HEP | HEP B (ENGERIX-B) | GLAXOSMITHKLINE BIOLOGICALS | 2 | EB9ZX | — |
| HEP | HEP B (ENGERIX-B) | GLAXOSMITHKLINE BIOLOGICALS | 1 | EB9ZX | — |
| HEP | HEP B (NO BRAND NAME) | UNKNOWN MANUFACTURER | UNK | — | — |
Negative titers after Hepatitis B vaccination (with unknown brand) as a child; Vaccine administered to pregnant patient; late second dose on March 2nd 2026; This non-serious prospective pregnancy case was reported by a consumer via call center representative and described the occurrence of therapy non-responder in a 30-year-old female patient who received HBV (Engerix B) (batch number EB9ZX) for prophylaxis. Co-suspect products included HBV (Engerix B) (batch number EB9ZX) for prophylaxis and Hepatitis B vaccine for an unknown indication. On 02-MAR-2026, the patient received the 2nd dose of Engerix B. On 29-DEC-2025, the patient received the 1st dose of Engerix B. On an unknown date, the patient received Hepatitis B vaccine. On 02-MAR-2026, an unknown time after receiving Engerix B, not applicable after receiving Engerix B and Hepatitis B vaccine and not applicable after receiving Engerix B and Hepatitis B vaccine, the patient experienced drug dose administration interval too long (Verbatim: late second dose on March 2nd 2026). On an unknown date, the patient experienced therapy non-responder (Verbatim: Negative titers after Hepatitis B vaccination (with unknown brand) as a child) and vaccine exposure during pregnancy (Verbatim: Vaccine administered to pregnant patient). The outcome of the therapy non-responder, drug dose administration interval too long and vaccine exposure during pregnancy were not applicable. Pregnancy exposure: Pregnancy Exposure (Engerix B): Trimester unknown Pregnancy Exposure (Engerix B): Trimester unknown Pregnancy Exposure (Hepatitis B vaccine): Trimester unknown Estimated Delivery/Due date: 10-JUL-2026 Pregnancy Outcome: Pregnancy was ongoing 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: 23-APR-2026 The adult pregnant patient reported that she had been fully vaccinated with Hepatitis B as a child back in the 90s and did not know the brand name. Her titers had come back negative, and her primary physician had recommended that she start the series over with Engerix-B. She received the first dose on 29-DEC-2025 and a delayed second dose on 02-MAR-2026. She was confused because she believed the doctor had messed up the schedule, since they had initially told her the schedule would be first dose, then second dose 2 months later, and third dose 4 months later. Potential interchangeability of vaccine brands was reported as a precautionary measure because the brand used for the childhood series was unknown. Negative titers were also reported as a potential adverse event in case the Hepatitis B series administered in childhood had been Engerix-B.