This case was reported in a literature article and described the occurrence of hepatitis B in a patient who received Hepatitis B vaccine for prophylaxis. Concurrent medical conditions included hemodialysis. Concomitant products included Hepatitis B vaccine, Hepatitis B vaccine and Hepatitis B vaccine. On an unknown date, the patient received the 4th dose of Hepatitis B vaccine. On an unknown date, unknown after receiving Hepatitis B vaccine, the patient experienced hepatitis B (serious criteria hospitalization and GSK medically significant) and shortness of breath (serious criteria hospitalization). On an unknown date, the outcome of the hepatitis B and shortness of breath were unknown. The reporter considered the hepatitis B and shortness of breath to be related to Hepatitis B vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of hepatitis B virus infection in a patient unspecified age and gender who was vaccinated with unspecified hepatitis B virus (HBV) vaccine (manufacturer unknown) for prophylaxis. The patient was started on haemodialysis in 2010. There was no evidence that the patient had ever been tested for HBV. The patient's vaccination status was also unknown. No information on patient's family history or concomitant medication was provided. On an unspecified at 0, 1, 2, and 6 months, the patient received 4 doses of unspecified HBV vaccine (administration route and site unspecified; batch number not provided for both) as recommended for haemodialysis patients. The age of vaccination was not provided. On an unspecified date in 2010, an unknown period after vaccination, the patient had post-vaccination testing and was positive for hepatitis B surface antibody (anti-HBs: 82 mIU/mL), indicating immunity to HBV. Post vaccination HBsAg testing was performed with a Food and Drug Administration (FDA)-approved assay at Laboratory was negative. As recommended for patients with demonstrated immunity, only anti-HBs was monitored routinely from 2010 to 2016 to ensure continued protection (anti-HBs more than 10 mIU/mL). In 2016, the patient was hospitalised for acute shortness of breath, and an HBsAg test was performed as part of a routine evaluation at laboratory and was found to be positive, indicating a current infection with HBV. The positive result was confirmed by additional testing at commercial and public health laboratories. Insufficient data were available to determine whether the patient acquired HBV infection before or after vaccination. After the positive HBsAg results were reported, an epidemiologic investigation was initiated to determine the cause of the false-negative test results and to identify any HBV transmission. A blood sample was collected in April 2017 and sent to the Centers for Disease Control and Prevention (CDC) to confirm the HBV diagnosis. CDC testing found high HBV deoxyribonucleic acid (DNA) levels (14,200,000 IU/mL), evidence of immunity (anti-HBs equal to 114 mIU/mL), and HBsAg positivity by one assay and negativity by another assay. Sequencing the S gene of HBV DNA identified an sG145R surface antigen mutation. This mutation is associated with false-negative results, which explains the failure of multiple tests to identify the patient as being HBsAg-positive. None of the contacts had prior evidence of HBV infection, all were screened by tests capable of detecting this mutant virus (using a suitable HBsAg assay or by HBV DNA), and all test results were negative, indicating no evidence of HBV transmission, despite the potential exposures to the HBV-infected patient. Family members without evidence of prior HBV vaccination were also advised to complete the HBV vaccination series. This case has been considered serious due to hospitalisation. Treatment was unknown. The outcome of the event was not reported. The authors stated, "Insufficient data were available to determine whether the patient acquired HBV infection before or after vaccination. This case highlights a unique challenge associated with detecting HBV infections when a surface antigen mutation is present". Following internal check, it was noticed that the initial GSK receipt date was incorrectly recorded as 14 January 2018 instead of 16 January 2019. Lab Comments: After the positive HBsAg results were reported, an epidemiologic investigation was initiated to determine the cause of the false-negative test results and to identify any HBV transmission. A blood sample was collected in April 2017 and sent to the Centers for Disease Control and Prevention (CDC) to confirm the HBV diagnosis. CDC testing found high HBV deoxyribonucleic acid (DNA) levels (14,200,000 IU/mL), evidence of immunity (anti-HBs equal to 114 mIU/mL), and HBsAg positivity by one assay and negativity by another assay. Sequencing the S gene of HBV DNA identified an sG145R surface antigen mutation. This mutation is associated with false-negative results, which explains the failure of multiple tests to identify the patient as being HBsAg-positive. None of the contacts had prior evidence of HBV infection, all were screened by tests capable of detecting this mutant virus (using a suitable HBsAg assay or by HBV DNA), and all test results were negative, indicating no evidence of HBV transmission, despite the potential exposures to the HBV-infected patient.