dull ache; had a rash 30 minutes into the infusion; got booster dose; got booster dose; This is spontaneous report from Pfizer. A contactable 78-year-old male consumer (patient) reported.  A 78-year-old male patient received bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Lot number: FC3183), via an unspecified route of administration in right arm on 23Aug2021 (at the age of 78-year-old) as dose 3, single for COVID-19 immunisation at pharmacy. Medical history included bronchial Asthma (the patient taking Privigen) and bronciectasis (the patient taking Privigen). Concomitant medications included immunoglobulin human normal (PRIVIGEN) taken for asthma, bronchiectasis from an unknown date in Jan2019 to an unspecified stop date; atorvastatin calcium (LIPITOR) taken for respiratory therapy, start and stop date were not reported (been on it 10 to 15 years). The patient previously took bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Lot number: EG9261), via an unspecified route of administration in right arm on 25Jan2021 (at the age of 78-year-old) as dose 1, single for COVID-19 immunisation and experienced pain, bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Lot number: EM9809), via an unspecified route of administration in right arm on 17Feb2021 (at the age of 78-year-old) as dose 2, single for COVID-19 immunisation and experienced pain, He took a statins for respiratory therapy (There are no other medications would be relevant. No further details provided), He had been taking the IVIG for 2 years and had no problem. He asked if there was a certain timeframe recommended to wait between having the booster vaccine dose and getting an infusion of Privigen immunoglobulin. He reported that for over 2 years he had been getting Immunoglobulin infusions (10% Privigen, dose of 30 grams) a 4-hour infusion, every 28 days. 1 week ago, for antibodies for increasing your level of immune therapy, he received the Covid vaccine booster dose. He reported that during his last infusion, which he received 1 week after the booster dose, he experienced a reaction, stating, "when we get our blood tested my immunoglobulin is usually up and that's good, but this time for the first time I had a rash 30 minutes into the infusion" and reported that the doctor had to stop the infusion early and told him that "we may be taking it too soon after getting the booster" and said "we should wait around 30 days and try again. He reported that he never had a reaction from the immunoglobulin and the only variable patient checked was getting the booster, the patient even checked that the bag they were infusing into my arm was the correct thing. He reported that now, he was perfectly fine "today" and plans to go back for another infusion 30 days from that Monday. He reported that he heard from his doctor and nurse that infusion patients or cancer patients should have a time lag between the shot and their next infusion or treatment. He reported that his doctor and nurse were not aware of any timeframe required in between the two products. Now calling to obtain more information. He then asked, "Who is the manufacturer of Privigen?" He reported that he received an infusion and took a picture of the product label but was not printed on there for him to know who the manufacturer was and if the booster dose was the same as both previous doses. He stated that even before they started the nurse said that she thought there was a time lag in between shot or booster or anything. When he had the first two in January and February there was a time that he went in for his IVIG and he had no reaction. It never even came up. It was not discussed, but for some reason the nurse said that before the procedure. The only new variable was the booster. As he understood, it was the same as the first two shots he had in January and February. He did not have a clue. Maybe it did not. He felt fine before the IVIG and felt fine now, and he had recovered nicely. The reaction occurred at the hospital in "PRIVACY". Rash was occurred on 30Aug2021 at 11:00. Once they stopped the treatment the rash was gone within 12 hours. Caller clarified that he would not define it as a rash. It was reddening of skin on face and chest. He has recovered 100 percent. It was 10% Privigen. Immunoglobuin was on the label. It says route for IV (intravenous). Dose was 30gram. It was prepared that morning when he showed up. He took a picture when they hung it to put it in the arm. The picture was what he was reading to provide product information. He did not see NDC, lot, and expiry on the picture he has. He started on an unknown date in Jan2019. He skipped the dose on the 30Aug2021 and will go 28 days out into September and he will go in a repeat the treatment. At that point they will see what the reaction was. The first two were given at the "PRIVACY". The third one was done at the "PRIVACY". No test was done. He waited 24 hours and it went away. It went away after stopping IVIG. The doctor and the nurses brought up the fact there may be a time lag that should occur from the time someone gets Moderna, Pfizer, or anything before doing this kind of thing including cancer treatments at infusion center. There was no prescribed time lag from when a person gets any of the shots until the next treatment. That was the unknown. He did not know if Moderna or Pfizer should came up with something to say wait such and such amount of time. After he had the next treatment, he will be happy the next day or whenever to call back and report any reaction or any difference going forward. He has been taking the IVIG (immunoglobulin) for 2 years and had no problem. The only variable was the booster shot. All three shots were given in right upper portion of arm. Over 24-hour period he had dull ache and it went away. That happened for all three shots. He needs to have his flu shot. Does Pfizer recommend waiting a certain period of time between the booster and the flu or shingles shot? The pharmacist and doctor asked to wait to one week. He knew that Pfizer was close to this because there are three or four other variants that will show up. This virus was not going away. We were going to be doing distancing and boosters forever. We would have to work as a team. The outcome of dull ache and had a rash 30 minutes into the infusion was reported as resolved on an unknown date.  Follow-up (09Sep2021): This is a follow up spontaneous report from a contactable consumer. This consumer reported in response to HCP telephonic follow-up activity that included: physician's mailing address added.  Follow-Up (17 Sep2021): Follow-up attempts are completed. No further information is expected.