COVID Vaccine Breakthrough Case  Pfizer Dose 1 1/29/21 (lot NA) Pfizer Dose 2 3/12/21 (lot NA) COVID Negative 11/28/21 COVID Positive 12/3/21  11/28/21: Patient is 77-year-old female past medical history significant for   Paroxysmal AFib rate controlled now, s/p colonic polyp removal,HFpEF, essential hypertension, hypothyroidism, osteoporosis presented to the ED with dizziness and black stool of 1 day   Patient endorses that since the last 2-3 weeks has been having dark stools.  On the day of admission patient noted to have a large bowel movement with initially maroon colored stool but mixed with blood.  Patient also endorses that has been progressively feeling dizzy that worsened since 1 day back   Patient had recent colonoscopy and was found to have multiple polyps which were removed and appointed follow-up after 3 years..   Patient also had intermittent mild chest discomfort however currently is chest pain-free.  In the emergency room lab was significant for mild hypokalemia of 3.3, elevated BUN/creatinine of 42/1.17 and with a ratio of 36.  Occult blood in the stool was positive; hemoglobin noted to be 8.1 than 7.3  CT abdomen and pelvis showed mild colonic diverticulosis.   Patient was given 1 dose of vitamin K in the emergency room  12/5/21: Patient is 77-year-old female with history of paroxysmal atrial fibrillation on Coumadin. She presented to the ER  12/28/2021 for complaint of tarry stool and dizziness.  Patient reported frequent episodes of loose dark stool for 2-3 weeks.  On day of presentation to the emergency room, she had large bowel movement with maroon-colored stool mixed with blood.  Patient also reported associated intermittent episodes of dizziness and lightheadedness for 1 day prior to presented emergency room.  Patient had recent colonoscopy with polypectomy. She was scheduled to have repeat colonoscopy in 3 years. Upon evaluation at the emergency room, she was hemodynamically stable.  BUN was at 42. Occult blood test was positive. Hemoglobin was at 8.1.  CT abdomen pelvis revealed diverticulosis without diverticulitis.  Patient was admitted for further evaluation of GI bleed.  Her home medication warfarin was held.  She was kept NPO and was started with IV fluid.  She was also started with IV Protonix.  Serial hemoglobin is a obtained and her hemoglobin dropped to as low as 7.0 gram/deciliter. Patient required transfusion with 1 unit of PRBC with appropriate increase in hemoglobin.  Patient underwent EGD and colonoscopy.  EGD was unremarkable.  Colonoscopy revealed diverticulosis without any active bleeding.  No obvious source of bleeding was identified.  Patient likely had diverticular bleed.  GI team cleared her for resumption of anticoagulant treatment.  She was started with home dose of warfarin 5 mg p.o. daily bridged with Lovenox.  Her hemoglobin remained stable.  A day after EGD/colonoscopy, patient had a spike of fever with T-max of 101.2° F. patient did not have any focus of infection.  She underwent fever workup including urinalysis, chest x-ray and nasopharyngeal swab for COVID-19.  Patient did not have any leukocytosis.  Urinalysis was suggestive of UTI.  Chest x-ray revealed left lower lobe infiltration/atelectasis. Nasopharyngeal swab came back positive for COVID-19. However, patient remained hemodynamically stable.  She was maintaining saturation on room air.  CRP and D-dimer were obtained.  D-dimer within normal limit.  CRP was slightly elevated.  Case was discussed with ID specialist who recommended patient to be evaluated for outpatient monoclonal antibody treatment.  Patient is being discharged home with an appointment follow-up with Dr. for evaluation of possible outpatient monoclonal antibody.  In the meantime, she is being discharged home with COVID-19 safe at home program.  Patient was instructed to self isolate at home for at least 10 days.  She is being discharged home with warfarin bridged with Lovenox.  She will have repeat INR BMP and CBC in 3 days time and is result to be followed by PMD.  Her home dose of warfarin to be adjusted accordingly.  Patient was instructed to monitor her pulse oximeter at home.  She was also instructed to watch for any signs of worsening of respiratory symptoms. She was instructed to come to the emergency room if worsening of respiratory status or desaturation as low as less than or equal to 90%.