Woke up in a fog and have not been able to shake it; Lethargic; Feeling very low energy; Feel very tired; Injection site was just a little sore; Arm being a little sore; Spontaneous report received on 12FEB2021.  A consumer reported that, "arm being a little sore" (PT: Pain in extremity), "woke up in a fog and have not been able to shake it" (PT: Feeling abnormal), "feeling very low energy" (PT: Asthenia),"lethargic" (PT: Lethargy), "feel very tired" (PT: Fatigue), and "injection site was just a little sore" (PT: Injection site pain) following the immunisation with BioThrax (anthrax vaccine adsorbed). On 11FEB2021, the patient received first dose of BioThrax injection in the arm. On the same day, the patient had little soreness in the arm. Next morning, the patient woke up in a fog and was not able to shake it. Despite of 7-8 hours of sleep, the patient felt very tired like he got an hour of sleep only. The patient felt lethargic with very low energy but no fever or body aches. The patient stated that the injection site was about what he was expecting, just a little sore. The outcome of the reported events was unknown at the time of report.  Company Comments: A consumer received first dose of BioThrax and on the same day developed injection site pain, arm was little sore (pain in extremity), and the next day the consumer was feeling abnormal with fatigue, lethargy, and asthenia even after having 7 to 8 hours of sleep. Further details of the events is limited. Injection site pain, pain in extremity, and fatigue are known effects of BioThrax, and the causality of these events is assessed as possible. Considering the case information, the causality of lethargy, asthenia, and feeling abnormal is assessed as possible with BioThrax.  Follow up information received from the consumer on 03MAR2021 which included time of administration of BioThrax, address of the reporter, gender of the consumer, date of birth, treatment medications, and outcome of the events.  It was updated that the male patient was administered BioThrax injection at 3 pm.   It was updated that all his symptoms last for about 24-36 hours, except for the sore arm which was persisted for 3 days. On 12-Feb-2021, his symptoms were resolved by 9 pm, except for the sore arm which lasted for three days. He used ibuprofen and Tylenol (paracetamol) for sore arm.  Company Comment: A consumer received first dose of BioThrax and on the same day developed injection site pain, arm was little sore (pain in extremity), and the next day the consumer was feeling abnormal with fatigue, lethargy, and asthenia even after having 7 to 8 hours of sleep. All events resolved within 24 to 36 hours except for pain in extremity which resolved after three days after taking tylenol and ibuprofen. Injection site pain, pain in extremity, and fatigue are known effects of BioThrax, and the causality of these events is assessed as possible. Considering the case information, the causality of lethargy, asthenia, and feeling abnormal is assessed as possible with BioThrax.; Sender's Comments: A consumer received first dose of BioThrax and on the same day developed injection site pain, arm was little sore (pain in extremity), and the next day the consumer was feeling abnormal with fatigue, lethargy, and asthenia even after having 7 to 8 hours of sleep. All events resolved within 24 to 36 hours except for pain in extremity which resolved after three days after taking tylenol and ibuprofen. Injection site pain, pain in extremity, and fatigue are known effects of BioThrax, and the causality of these events is assessed as possible. Considering the case information, the causality of lethargy, asthenia, and feeling abnormal is assessed as possible with BioThrax.