Good day, mate has just been diagnosed with PV, having Jak2 mutation. Have had phlebotomy - several to get into range. Now will start Hydrea. Interested in side effects and how long they occur. I'm sure there will be many questions to come but key ones I have are (1). if JAK2 inhibitor drug is used to stop production, is there any information that there is a possibility once the inhibitor is stopped, the high production of blood cells may stop as well? The reason I ask, is that I was getting severe migraines. I could not get rid of the pain. My doctor put me on a pain inhibitor as she thought maybe the pain transmitters were not 'shutting off'. After several days 10 - 14, I stopped taking the pain inhibitor drugs and the pain was gone. Thinking could this be the same with the JAK2 inhibitor drugs. (2). Are there any relations between blood disorders, like PV - high platelets, high hemoglobin and high red blood count being related to the Covid19 vaccines - specifically Pfizer? Thank you in advance for your comments.