My arm felt a little heavy; This is a spontaneous report received from a contactable consumer (the patient). A 62-year-old female patient received the first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, lot number was unknown) via an unspecified route of administration on 01Apr2021 at single dose for COVID-19 immunisation. Medical history included ongoing memory issues, ongoing brain fog, got COVID in the fall, ongoing headache, felt feverish and headache affected short term memory. The patient's concomitant medications were not reported. The patient reported she did not have any reactions. She didn't feel it when she got the shot. She woke up the next morning and her arm felt a little heavy but that's it (02Apr2021). The patient already had antibodies. She got covid in the fall. She had her second dose scheduled for 29Apr2021 and she drove there but something told her she shouldn't get it. She had struggled with brain fog and memory issues and she was still having this issue. She was fearful. She was going to give blood again, and would find out if she have antibodies; She didn't want another headache and do damage to brain. She always had an excellent memory but she didn't anymore. It was frightening. She had appointment the next with her HCP. She was 62 years old; She didn't need to be messing with her brain. The patient asked if any people with brain fog studies or studies with people with too many antibodies. She didn't know how to make this decision. She still getting headachey all the time. After she got the covid infection she had a headache, felt feverish, no body ache. She wasn't tired. And lingered on all this time. In the past her head was so clear in the morning and she couldn't do anything. Currently she just sit and stare and try to focus and she was still struggling, not as bad as it was. She was wondering if there were studies. She wouldn't mind being part of something. The patient was calling because she actually had COVID and unfortunately in the fog and she had a really, really bad headache and a fever, but by the next day she was better, but she had the lingering headache and off and on headache, she was not somebody who often get headache and it affected her short term memory too and she got the first vaccine on the first of April and she was schedule to get the second one on the 29th but when she drove all the way down there, talk to pharmacy and she just have this overwhelming feeling that she shouldn't be getting it that day and she didn't feel that it all before she left, but her daughter didn't feel anything after got the vaccine at the first time, the patient did not feel anything either, her daughter got really sick (severe headache) from the second dose. The patient thought she just do not like, she wasn't ready that day to get this but currently she can find fear is that, whatever happen to her when she got Covid still have to be, her fear was that if she go and got the second vaccine, was she end up with another headache and do more damage. The patient further stated while she was getting her first vaccine she have a rare blood type, so she tried to donate blood when she can. And she did donate blood, before she got vaccine and that's how she was confirm that it was indeed Covid that she had because they need give blood to find out 100% pretty much that you have it or not. So right now she was headache and she have antibodies, basically a headache and antibodies when she got that blood tested shortly before giving the first vaccine and then she got the first vaccine so she was feeling like she must have quite a few antibody then. When probed for second shot, the patient stated "No", she did not get it on 29, she was panic, she changed her mind , she didn't want to get the second vaccine and end up with the another severe headache in the damage to her brain. The patient had no side effect whatsoever from the vaccine nothing. She didn't have any side effect, she didn't have any side effect first time either but her headache all started back in 2020 in the fog, when she actually got covid. The patient stated asked if it was necessary to her to get the second vaccine, she did not want to get ever headache. The outcome of event "my arm felt a little heavy" was unknown.  Information about lot/batch number has been requested.