This case was reported by a other health professional via call center representative and described the occurrence of therapy non-responder in a 17-year-old female patient who received ENGERIX B adult. Co-suspect products included ENGERIX B adult, ENGERIX B adult, Hepatitis B vaccine, Hepatitis B vaccine and Hepatitis B vaccine. On 13th January 2014, the patient received the 1st dose of ENGERIX B adult. On 14th March 2014, the patient received the 2nd dose of ENGERIX B adult. On 6th August 2014, the patient received the 3rd dose of ENGERIX B adult. In 2008, the patient received the 1st dose of Hepatitis B vaccine and the 2nd dose of Hepatitis B vaccine. In 2009, the patient received the 3rd dose of Hepatitis B vaccine. In January 2014, not applicable after receiving ENGERIX B adult, ENGERIX B adult and ENGERIX B adult, 6 years after receiving Hepatitis B vaccine and Hepatitis B vaccine and 5 years after receiving Hepatitis B vaccine, the patient experienced therapy non-responder. On 5th August 2015, the patient experienced therapy non-responder. On an unknown date, the patient experienced drug dose administration interval too long and drug dose administration interval too short. On an unknown date, the outcome of the therapy non-responder, therapy non-responder, drug dose administration interval too long and drug dose administration interval too short were unknown. It was unknown if the reporter considered the therapy non-responder to be related to ENGERIX B adult, ENGERIX B adult, ENGERIX B adult, Hepatitis B vaccine, Hepatitis B vaccine and Hepatitis B vaccine. It was unknown if the reporter considered the therapy non-responder to be related to Hepatitis B vaccine, Hepatitis B vaccine and Hepatitis B vaccine. Additional details provided are as follows: Healthcare professional reported that, the patient completed two series of Hepatitis B vaccine and underwent titre testing after completion of both the vaccination series, which showed patient was non-reactive to Hepatitis B surface antigen. Initial series with Hepatitis B vaccine was started in 2008 and completed in 2009 (the reporter was unsure which Hepatitis B product was used in the initial series). In January 2014, approximately 6 years after receiving the 1st and 2nd doses of Hepatitis B vaccine and approximately 5 years after receiving the 3rd dose of Hepatitis B vaccine, the patient performed titre testing and was found to be negative (non-reactive) for Hepatitis B surface antigen. After which the patient started on her second series of Hepatitis B vaccination with ENGERIX B adult. On 13th January 2014, the patient received her 1st dose of ENGERIX B. On 14th March 2014, the patient received her 2nd dose of ENGERIX B, which led to lengthening of the schedule. On 6th August 2014, the patient received her 3rd dose of ENGERIX B, which led to shortening of the schedule. On 5th August 2015, approximately 7 years after receiving 1st and 2nd doses of Hepatitis B vaccine, approximately 6 years after receiving 3rd dose of Hepatitis B vaccine, 569 days after receiving the 1st dose of ENGERIX B adult, 509 days after receiving the 2nd dose of ENGERIX B adult, 364 days after receiving the 3rd dose of ENGERIX B adult vaccines, the patient returned for titre testing and again the results were negative (non-reactive) for Hepatitis B surface antigen, causing the patient to be a non-responder to therapy. No further information was reported regarding the event.