Blood counts, white and red, went down substantially after 2nd dose of Covid-19 vaccine/blood is lower than average/blood counts were lower than what the caller should have had; Blood counts, white and red, went down substantially after 2nd dose of Covid-19 vaccine/blood is lower than average/blood counts were lower than what the caller should have had; ANC 06Apr2021: 4/ANC 05May2021: 1.1; This is a spontaneous report from a contactable consumer.   An 84-years-old female patient received second dose of BNT162B2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Lot Number: EN6204 and Expiration date was not reported), via an unspecified route of administration, in left arm on 16Mar2021 14:00 hours as single dose for covid-19 immunization. Medical history included ongoing cancer from 34 years, ongoing thyroid, ongoing high blood pressure from 2006, ongoing memory loss from 2006 (memory was something that she really struggles with), deterioration of spine and sleep apnea from 2020 (almost a year ago and does not take any medications for it) to ongoing. Patient sees a doctor for the deterioration of her spine but she does not take medication for it and reported that the deterioration of her spine did not become bothersome until she was about 50 years old. Patient had lost 6 inches due to problems with her back and deterioration of her spine and stated that she was now 5 feet tall with maybe a half inch, as she used to be used to be 5'6", but that was a whole different issue. Concomitant medications included 75mg palbociclib (Ibrance) taken daily (Lot Number: EE8028, Expiration date: Jun-2022) from 2015 for cancer, cyanocobalamin (Vitamin B 12), taking daily, for too many years and ongoing to increase red blood cell count; 25mg losartan, 4 times a day, for high blood pressure from an unspecified start date (can't remember when she started taking) and ongoing; memantine hydrochloride (Namenda) taken at a dose of 10 mg, twice a day, for an unspecified indication from 2006 and ongoing; letrozole taken at a dose of 2.5 mg, daily, for cancer from 2015 and ongoing; levothyroxine taken at a dose of 0.05 mg for thyroid from an unspecified start date and ongoing; methylphenidate taken at a dose of 10 mg, daily for an unspecified indication from 2010 and ongoing; vitamin B complex taken daily for an unspecified indication from an unspecified start date and ongoing; ascorbic acid (Vitamin C) taken daily for an unspecified indication from an unspecified start date and ongoing; calcium taken daily for an unspecified indication from an unspecified start date and ongoing; multivitamin taken daily for an unspecified indication from an unspecified start date and ongoing. Patient reported that she thinks perhaps the drug Namenda and methylphenidate was for attention deficit, but she also takes a medication for memory. Letrozole goes along with the Ibrance. Patient does not know what the strengths of B complex, Multivitamin, Calcium, Vitamin C, as these are over the counter vitamins she takes. Patient just grabs whatever was on the shelf at the store. Patient was taking the vitamins because she had always been kind of puny and because if she had a complaint about this or that, something would be suggested. Patient started taking iron and stuff when she was 11 or 12 years old and has been taking vitamins all along. Patient stated that everything was so involved with her medications and it was hard for her to keep track of them. Historical vaccine included flu shot every year and some years she gets a pneumonia vaccine, patient reported that her last vaccination was when she got her flu shot in Oct2020 and BNT162B2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot Number: EN6198 and Expiration date was not reported), via an unspecified route of administration, in left arm on 19Feb2021 as first dose, single for covid-19 immunisation. No prior vaccinations (within 4 weeks). Patient reported that WBC count of 6 was as good as she had ever gotten her white count and she was so proud. On 06Apr2021, WBC count was 6, RBC was 3.73 and ANC (Absolute neutrophil count) was 4. On 05May2021, patient blood counts, white and red, went down substantially after 2nd dose of Covid-19 vaccine/blood was lower than average/blood counts were lower than what the caller should have, and ANC was 1.1. Patient had no emergency room and physician office due to adverse events. Patient was taken off Ibrance due to low blood counts. Patient reported that she asked the pharmacist if there would be any reaction between the Ibrance and the Covid-19 vaccine.  Patient reported that at the time that she talked to the pharmacist, there was no information regarding Ibrance and the Covid-19 vaccine. Patient reported that she waited a couple of months and called the pharmacist again. Patient reported that the pharmacist had information when she called back that the Ibrance in her body was going to be resilient or against the virus in the Covid-19 vaccination. Patient reported that due to the resilience of Ibrance against the Pfizer Covid-19 vaccine, patient's protection benefit of the Covid-19 vaccine may not be as high as other people.  Patient was informed that she could receive a maximum efficacy of 50% for the Covid-19 vaccine, but that the efficacy of the Covid-19 vaccine would probably only be 20-30% due to the use of Ibrance. Patient did not have any sign with either dose of the Covid-19 vaccine that she got anything and may not had gotten much vaccine working in her body. Patient had a question regarding the Pfizer covid vaccine booster shot. Patient reported that she usually gets 2 blood lab reports, but her doctor was cutting it down to 1 blood lab every 4 weeks and stated that cutting the blood work down was going to complicate her routine. Patient reported that there were so many times that she can't make 3 weeks in a row on Ibrance.  Patient reported that she will do 2 weeks on Ibrance, then lay off for a week, and then do another week. Patient was currently off of Ibrance for 2 weeks. The patient underwent lab tests and procedures which included ANC: 4 on 06Apr2021 and 1.1 on 05May2021, red blood cell count: 3.73 on 06Apr2021 and 3.35 on 05May2021, white blood cell count: 6 on 06Apr2021 and 2.4 on 05May2021. The outcome for all the events was unknown.   No follow-up attempts are needed. No further information is expected.