Body shaking; muscle spasm; intense body shaking; muscle spasm; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the parent.  A 31-year-old male patient received bnt162b2 (COMIRNATY), administered in arm, administration date 22Apr2021 (Lot number: EW0172) at the age of 31 years as dose 2, single and administered in arm, administration date 31Mar2021 (Lot number: EP7534) as dose 1, single for covid-19 immunisation. The patient's relevant medical history was none. There were no concomitant medications. The following information was reported: TREMOR (non-serious) with onset 31Mar2021, outcome "recovered" (2021), described as "intense body shaking"; MUSCLE SPASMS (non-serious) with on-set 31Mar2021, outcome "recovered" (2021), TREMOR (non-serious) with onset 22Apr2021, out-come "recovered" (2021) and all described as "Body shaking"; MUSCLE SPASMS (non-serious) with onset 22Apr2021, outcome "recovered", described as "muscle spasm".  Additional information: The reporter (Father), calling on behalf of his son, who received both doses of Pfizer Covid-19 vaccine. Reporter stated that after about 10 hours after both doses he had intense body shaking, muscle spasm that lasted for 2 mins each time event, late afternoon early evening both times. The doctor didn't really don't know what to tell about it withheld they don't advice getting booster, if he have reaction to it. Reporter stated in his particular case, his doctor has no answer for him about why he had these particular reactions, and the withheld form to check the booster, where he went, has a bottom disclaimer that if you had adverse reactions to either shot not to have the booster. The reporter was kind a afraid about that we wonder what is the alternative if withheld is advising against taking a booster under his condition anybody's condition to that matter. The reporter clarified that with both injections his son had the same reactions. Reporter stated had the same unfamiliar reactions each time. Reporter stated, has not seen anything written or talked about on this. Reporter stated that his son has recovered from the events but was scared to get the booster. His son's last dose was in Apr2021, reporter does not have the exact dates of the vaccine administration. Reporter stated, in his particular case, his doctor has no answer for him about why he had these particular reactions, and the withheld form to check the booster, where he went, has a bottom disclaimer that if you had adverse reactions to either shot not to have the booster. He is kind a afraid about that we wonder what is the alternative if withheld is advising against taking a booster under his condition anybody's condition to that matter. Reporter stated lot of people are getting pretty discouraged about this. I don't think my son is gonna go to those processes to a third party again. If the alternative is a reaction plan, there's no alternative to the booster. Most of the reaction plans were already publicized but you know, monoclonal antibody treatment, it seems to be very popular at the time, as far as a reaction to getting the symptoms so I don't think that's the issue. The issue is you know being proactive, what can you do ahead of time if there's no alternative to the booster then I don't think, reaction plans I don't see any problem. Reporter stated, I'm not seeing any reports of this particular reaction especially having the same reaction twice, once after each shot, mean generally there's seems to be a variety of reactions but nothing like this. Reporter stated that they were the standard approved time apart. The intense reactions lasted about two minutes after onsets the person stayed home. The doctor was consulted afterwards but could not offer any opinion of cause or advice. The (name Withheld) applications for booster if you have had adverse effects in response to previous covid vaccine injections. The vaccination Facility was a large drive through vaccination event. The any AE(s) did not require a visit to emergency room, physician office, he called the physician the next day. Prior Vaccinations (within 4 weeks) If applicable, list any other vaccinations within four weeks prior to the first administration date of the suspect vaccine was unknown. The AE(s) following prior vaccinations was none. The family medical history relevant to ae(s) was none. The relevant tests was none.   No follow-up attempts are possible. No further information is expected.