Age: 78.0
Sex: M
Vaccine: COVID19, COVID19
Symptoms: Headache, Pruritus, Urticaria
Clinical narrative: Skin started itching everywhere; Skin started feeling sunburned everywhere; Some little raised bumps on his stomach like a little area of that itched/On his stomach he had the little welts that started to itch; This is a spontaneous report from a contactable consumer or other non hcp. A 78-years-old male patient received bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection), dose 2 via an unspecified route of administration, administered in Arm Left on 17Feb2021 11:00 (at the age of 78 years old) (Batch/Lot Number: EN6201; Expiration Date: Jun2021) as single dose for COVID-19 immunisation. Medical history included allergies. The patient's concomitant medications were not reported. Previously the patient received bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection), dose 1 via an unspecified route of administration, administered in Arm Left on 21Jan2021 (Batch/Lot Number: EL3249; Expiration Date: Jun2021) as single dose for COVID-19 immunisation and experienced itching all over his body. States he took Benadryl regularly for the side effects but after 4-5 hours of taking the Benadryl, his symptoms returned. After a few days the itchiness resolved. States he went to allergist and received a prescription for prednisone, epipen and Benadryl with instructions for use by allergist. He was instructed to take Benadryl prior to the 2nd shot of the vaccine. He was instructed to take Benadryl if reaction post vaccine shot was mild and instructed to use epipen and call if he had a bad reaction. Also instructed to take Prednisone if Benadryl was not working. Received his second vaccine shot yesterday and, in the afternoon, developed a sun burning sensation on his skin in addition to itchiness and a welt on his stomach. The patient took Benadryl and within 30 mins symptoms resolved. He had had to take Benadryl regularly (every 4-5 hours) as his symptoms returned about 4 hours after a dose of Benadryl. States he has not needed the epipen or prednisone and would like to know if Benadryl deactivates effectiveness of vaccine. The patient wanted Pfizer to conduct clinical trials/have information on how antihistamines may interfere with the vaccine and asked if there is a blood test he can take after a period after the second vaccine dose to determine effectiveness of the vaccine. Concerned about his reaction as wondering if he should avoid the vaccine if a booster is indicated down the road and especially if his reaction is consider serious reactions and asked about the half-life. This consumer called to ask if Benadryl he has taken would affect the efficacy of the Pfizer COVID-19 Vaccine that he has been administered. He has allergies so he took a Benadryl approximately 2 hours before being administered the vaccine around 11:00. After second dose was administered, he felt ok, he waited on site for about 30 minutes for monitoring like you are supposed to. About 2 hours after vaccine was administered his skin started feeling sunburned everywhere and skin started itching everywhere. In response to events he took another Benadryl. About 30 minutes after taking Benadryl the events went away. About 4-5 hours later the events came back the same way as when they started. He had some little raised bumps on his stomach like a little area of that that itched. His body itched all over but it felt horrible sunburned. He took another Benadryl and in about 30 minutes the events kind of cleared up, it was good. About 4 hours after that the Benadryl wore off, the events came back so he took another Benadryl. Today the events are ongoing but a lot milder than it was on 17Feb2021. It seemed like every 4-5 hours the events would come back but milder today. His question is since he had to take Benadryl or he would have been itching all over the place; and he did not want to go to emergency room which he probably would have had to if he had not taken the Benadryl; and he would like an answer, not a maybe; since he had to take Benadryl and taken Benadryl again today and got the Pfizer COVID-19 Vaccine shot yesterday, is the Benadryl counteracting the efficacy of the Pfizer COVID-19 Vaccine. He has had no other vaccines or immunizations other than the first dose of Pfizer COVID-19 Vaccine. He took Benadryl pill 2 hours before he went for the second dose of Pfizer COVID-19 Vaccine; had the second dose of Pfizer COVID-19 Vaccine shot, nothing happened until he would say maybe around 13:00; because he waited 30 minutes after the shot; got in the car and came home. Around 13:00 he started getting the itchiness but this time his skin felt like it was sunburned everywhere. He was not out in the sun, it is snowing there, there are clouds, no sun; skin all over felt like it was sunburned. On his stomach he had the little welts that started to itch; He took Benadryl. He did not want to use the Epi-Pen because the allergist said he had to call # if he used the Epi-Pen and he did not want to do that. Benadryl cleared it up; did not make it go away; about 4 hours later events started back; so he took Benadryl again; and about 4 hours later events came right back; it did that all night. Today, right now, he took a Benadryl let's say about 4-5 hours ago and events are not coming back like that. If events do not come back, he probably won't take another Benadryl. Events are a lot milder now, seems like they are going away. The Benadryl works. His concern is because he did hear on TV from one of those TV doctors on one of those daily regular daily talk shows that his idea was, and caller reported it is unknown how accurate the information is; but the doctor said avoid taking medications like Aspirin, Tylenol or antihistamines, all that stuff when you get your shot because it could affect the efficacy of the shot. Caller is not sure he is right; because his allergist just said take the Benadryl in case of anaphylactic shock which he did not have. Would like to know if this a waste of all this stuff he did because what they did now was he interfered with the action of the vaccine. No other vaccines were administered on same date with the Pfizer vaccine considered as suspect. The adverse events required visit to Physician office and not required to visit Emergency room and was not hospitalized. Therapeutic measures were taken as a result of the events. The outcome of the events was recovering.  No follow up attempts are possible. No further information is expected.