I am confused; in bed for 3 days; weakness; she had fever; body aches; she had a bad case of flu; I received a third Pfizer COVID-19 vaccine on 20Aug2021; I received a third Pfizer COVID-19 vaccine on 20Aug2021; This is a spontaneous report from a contactable consumer or other non-HCP (patient herself) via Medical Information Team. A 73-year-old female patient received BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- FC3181) via an unspecified route of administration administered in left arm on 20Aug2021 as dose 3 (booster), single (at the age of 73-years-old) for COVID-19 immunization. Vaccination facility type was reported as Pharmacy/Drug Store. Vaccine was not administered at (Privacy) facility. Patient medical history included ongoing asthma severe asthma diagnosed when she was a little girl in the 1950s, ongoing chronic obstructive pulmonary disease diagnosed just in the past 15 years. The concomitant medications included influenza vaccine inact split 3v (FLUZONE HIGH DOSE) at a dose of 0.7 ml taken for an unspecified indication from 21Sep2021 to an unspecified stop date; prednisone taken for an unspecified indication, start and stop date were not reported. Historical vaccine included BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- ER8737) via an unspecified route of administration administered in left arm on 05Apr2021 in the afternoon between 14:00 and 16:00 (as reported) as dose 1, single and received BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- EW0167) via an unspecified route of administration administered in left arm on 27Apr2021 in the afternoon between 14:00 and 16:00 (as reported)  as dose 2, single for COVID-19 immunization. On her first dose, she experienced a little weakness. On her second dose of vaccination she had a feeling of being dragged. The patient stated that she was confused. On 05Apr2021, she received her first Pfizer, COVID-19 vaccine. On 27Apr2021, she received her second Pfizer, COVID-19 vaccine. She received the third Pfizer COVID-19 vaccine on 20Aug2021 with lot number that looked like FC3181. She states all three doses of the Pfizer COVID Vaccine were administered to her left arm. She was told it was the Pfizer Booster. Now she was hearing on the news that the Pfizer booster was just approved and released this week. She does have health issues and she was 73 years old. She confirmed that she got 3 doses of the Pfizer BioNTech covid-19 Vaccine. She also stated that she felt like she was being dragged down (unclear if it was the second or third dose). She also stated that on her third dose, she was in bed for 3 days. She also confirmed that she had health issues. She received three doses of the Pfizer BioNTech COVID19 vaccine and after the first dose she experienced a bit of weakness and felt weak and after the second dose had a feeling of being dragged down and after the third dose she was in bed for three days straight. Stated she had been on Prednisone for about a year. She stated she called because she was concerned because she got the third dose of the Pfizer COVID Vaccine and then like 2 weeks later they announced the third dose had been approved and showed withheld getting the third dose and she asked herself if the third dose had just been approved what did she got and called the CDC and called back again and they were not much help, stated said the third dose of the vaccine was approved and told her they are all the same and have the same things in them regarding the Pfizer Covid vaccine doses and it is just in three different doses and she wonders why they said the third dose of the Pfizer Covid vaccine was just approved. Stated she did not notice her symptoms if she had not been looking out for them regarding the first dose of the Pfizer COVID-19 vaccine, stated it was the third dose of the vaccine that hit her like a ton of bricks and it was horrible and her symptoms resolved by about the fourth day and she was fine, stated the first day she took the third dose of the vaccine she was ok that day and then the following day on 21Aug2021 that was when it hit and then on 22Aug2021 or 23Aug2021, it was easing up and on 24Aug2021 her symptoms were gone in regard to the weakness and everything, stated she had fever, body aches and it was like she had a bad case of the flu. Stated the pulmonologist told her it was good to get the symptoms she had and it means the vaccine was working and stated she was afraid of the side effects and the doctor told her to make sure she had enough food in the house in case she had to stay in bed if needed and if she gets bad side effects and he taught her about immunity. Stated after the third booster dose of the Pfizer COVID19 vaccine she did get a flu shot and the flu shot was last Thursday and was the higher dose one of Fluzone HD 0.7mL injection and she stated her HCP told her not to get the Fluzone HD and it did not matter but someone disagreed with him and gave her the higher dose of the flu vaccine and that was on 21Sep2021. The reported seriousness of the events was non-serious.  The adverse events she was in bed for 3 days, weakness, she had fever, body aches, she had a bad case of flu, she was confused did not result in a visit to the emergency room but resulted in a visit to physician office. Description of complaint included she stated that she called because she was concerned because she got the third dose of the Pfizer COVID Vaccine and then like 2 weeks later they announced the 3rd dose had been approved and showed (Privacy) getting the 3rd dose and she asked herself if the 3rd dose has just been approved what did she get and called the CDC and called back again and they were not much help; states withheld said the 3rd dose of the vaccine was approved and told her they are all the same and have the same things in them regarding the Pfizer Covid vaccine doses and it is just in three different doses and she wonders why they said the 3rd dose of the Pfizer Covid vaccine was just approved. On 21Aug2021, she was in bed for 3 days, weakness, she had fever, body aches, she had a bad case of flu. The outcome of the event she had a bad case of flu, bedridden, weakness, fever, body aches was resolved on 24Aug2021. The outcome of the event she was confused was unknown.   No follow up attempts are possible. No further information is expected.   Follow-Up (13Oct2021): Follow-up attempts are completed. No further information is expected.