Sore throat; Exhaustion; I'm having more relapses than usual, it's more hyped than in old age past. My immune system was stimulated to hyper level.; I'm having more relapses than usual, it's more hyped than in old age past. My immune system was stimulated to hyper level.; Brain fog; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 76 year-old female patient received bnt162b2 (BNT162B2), administration date 01Feb2021 (Batch/Lot number: unknown) at the age of 76 years as dose 2, single for covid-19 immunisation. Relevant medical history included: "immune issues" (unspecified if ongoing); "autoimmune disorder" (unspecified if ongoing); "chronic fatigue syndrome", start date: 1987 (unspecified if ongoing); "respiratory virus", start date: 1966 (unspecified if ongoing), notes: had a respiratory virus in 1966. The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (First dose), for Covid-19 Immunization. The following information was reported: OROPHARYNGEAL PAIN (non-serious) with onset Feb2021, outcome "recovering", described as "Sore throat"; FATIGUE (non-serious) with onset Feb2021, outcome "recovering", described as "Exhaustion"; CONDITION AGGRAVATED (non-serious), IMMUNE SYSTEM DISORDER (non-serious) all with onset Feb2021, outcome "recovering" and all described as "I'm having more relapses than usual, it's more hyped than in old age past. My immune system was stimulated to hyper level."; FEELING ABNORMAL (non-serious) with onset Feb2021, outcome "unknown", described as "Brain fog".  Additional information: 2 weeks in middle of February, she had a respiratory virus in 1966, she was hospitalized for this, and she was exposed to cold, she got the same symptoms she experienced then,  total exhaustion sore throat, brain fog. Her system is over reactive. Her immune system is weakened. 2 weeks after the second one in the middle of February, she was exposed to cold, and started experiencing, sore throat, and total exhaustion, symptoms that she had with early respiratory virus. She was told as she will age, her immune system would weaken and reactions would get less and less, that seemed to be happening, would only last 5 months, then 4 months, then down to 1.5 Months, but this time which makes it interesting, it has gone on for 3 Months. She was having more relapses than usual, it was more hyped than in old age past. Her immune system was stimulated to hyper level. The patient has received both Pfizer vaccines, second dose was 1Feb2021 and the caller was concerned about her immune system, states she has a history of autoimmune disorder and was concerned about getting a booster shot. The caller reports 2 weeks after her second vaccine she said she was exposed to cold air and started having symptoms related to her history with respiratory viruses. Caller states her system is over reactive and her immune system is weakened. The caller experienced sore throat and total exhaustion and brain fog. Agent states the patient was told at her age with her immune system it would weaken and states her symptoms have gone on for 3 months. That she was having more relapses more than usual. states that she had 8 replapses of her symptoms in the past 3 months. States she felt like she would be getting better and then they would return. States she has definitely improved. She does have a history of immune issues, diagnosed in 1987 as chronic fatigue syndrome because they did not know what immune issues were then. States she thinks she had Covid symptoms in 1966. She heard that people vaccinated early would need a booster coming up in September.  She was concerned with the booster shots coming up in September, not feeling like getting one. She was just getting over this episode. She was told that the need for a booster dose of Pfizer-BioNTech COVID-19 vaccine based on duration of protection or impact of variant strains has not yet been determined. On Feb25, Pfizer and BioNTech announced they initiated an evaluation of the safety and immunogenicity of a potential third dose of the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) to understand the effect of a booster on immunity against COVID-19 caused by the currently circulating and potential newly emerging variants. It is important to have a vaccine technology that allows us to both provide boosting doses if needed and to address potential changes in the virus itself if a new variant emerges that the vaccine does not protect against.  While we have not seen any evidence that the circulating variants result in a loss of protection provided by our vaccine in our laboratory studies, we are taking multiple steps to be ready in case a strain becomes resistant to the vaccine.  The administration of more than a 2-dose series of Pfizer BioNTech COVID-19 Vaccine is not approved. Pfizer is unable to make any recommendations regarding administration of a booster dose of Pfizer-BioNTech COVID-19 Vaccine; Pfizer does not suggest or recommend the use of the vaccine in any manner other than as described in the authorized Information. Note to frontline: This FAQ should only be used if someone specifically asks about the Pfizer statement on booster doses.   No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.