This 42 year old USAF services member reported receiving five Anthrax (AVA) vaccinations in 1999 with no remembered adverse events. He reported experiencing a sudden severe headache following receipt of Anthrax vaccine#6 06 Nov 2000. He described this headache as a constant throbbing excruciating pain 10/10 to the crown of his head with no other symptoms remembered ("too long ago to remember"). He denied any previous headaches, migraines, illness, trauma, or medical problems. He reported mild seasonal sinusitis. He sought medical care for "severe headache x 24 hours" at Hospital and was transported to Hospital where MRI was completed with normal results. He doesn't remember how long it took his HA to resolve or how much time lost from work. His concerns center on resumption of the Anthrax vaccine and possible reoccurrence of the headache. He denied any reoccurring headache since 2000 matching the 1999 episode. Evaluation by physicians around February 2007 diagnosed him with history of "cluster headaches" stating "it was coincidence that the headache came after the shot". Available medical records from 1999-2000 documented complaints of headaches x 2 weeks on 23 June 1999. He was diagnosed with musculoskeletal and treated first with Naproxen and Flexeril the Toradol and Midrin. In July 1999, he complained of a one month history of recurrent headaches described as throbbing dull pain about right eye, some photophobia, some nasal congestion, and no nausea. One episode had pain behind right ear to eye. Headaches would last several hours to days with sudden oneset. He smokes up to 1ppd of Cigarettes. His diagnostics included right Otitis media (ROM), URI and cluster headaches. Head CT 7/21/1999 documented sphenoid sinus mucosal disease otherwise normal. Midrin initially relieved headaches and later relieved with Imitrex.  By August 1999 his headaches were daily to right temporal and frontal regions relieved with Advil and nasal Lidocaine. He was diagnosed with sinusitis and treated with Septra and Entex with good relief of symptoms. Neuro evaluations in June 1999 were normal. 19 September 2000 his records show treatment for complaints of headaches- first 2 weeks ago for 3 hours and again 23 Sept 2000 x 2 hours. His exams were normal and he was diagnosed with ROM and migraine/cluster headaches. He was treated with Naproxen, Cafergot then Entex and Amoxicillin and finally Imitrex before headache resolved. By May 2007 he presented to ED with "his third episode of cluster headaches". His first cluster was in 1999, second in Sept 2000 (18 months after AVA#6) and now. His headache again resolved with Imitrex 6mg. Neurology evaluation Jun 2007 documented severe right right hemicranial headaches in evening with ipsilateral rhinorrhea and photophobia x1 hour. These headaches occur once a day for 1-2 months then spontaneously subside. Neuro exam was normal with MD diagnosing cluster headaches. A taper of Prednisone was given and started on Verapam with SQ Imitrex prn. His records remain sporadic with next evaluation in Aug 2008 where he reported his last cluster headache was around April-May 2008 relieved with Imitrex. He was given a prescription refill for "ounce a year cluster headaches". Medications on Aug 2008 are only Asthma medications.