CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; REVACCINATION WITH DIFFERENT COVID-19 VACCINE; This spontaneous report received from a patient via other company (Pfizer Inc.) concerned a female patient of unspecified age, race, ethnicity. Initial information was processed along with the additional information received on 08-FEB-2023.  The patient's height, and weight were not reported. The patient's concurrent conditions included: osteoporosis, depression, tinnitus, shellfish allergy, grasses allergy, and dust allergy. The patient received first dose with covid-19 vaccine ad26.cov2.s (Dose number in series 1), (suspension for injection, route of admin not reported, batch number: 201A21A, expiry: UNKNOWN) dose was not reported, single dose 1 total administered on 06-APR-2021 for covid-19 prophylaxis. Concomitant medications included ascorbic acid/calcium/minerals nos/retinol/tocopheryl acetate/vitamin b nos/vitamins nos/zinc, colecalciferol, estradiol, fluoxetine, loratadine, and spironolactone. The patient additionally received 2 doses (second and third dose) with Non-company suspect vaccine Moderna covid-19 vaccine, (elasomeran), (Dose number in series 2), (batch number: 058H21A, expiry: UNKNOWN, form of admin, route of admin were not reported) dose was not reported, administered on 01-DEC-2021, and (batch number: 001M21A, expiry: UNKNOWN, form of admin, route of admin were not reported) dose was not reported, administered on 27-APR-2022 for covid-19 prophylaxis. It was unknown whether patient had any adverse events following vaccination (Dose number in series 2). The patient also received fourth dose with Non-company suspect vaccine Moderna covid-19 vaccine, (elasomeran), (Dose number in series 3), (batch number: 053D22A, expiry: UNKNOWN, form of admin, route of admin were not reported) dose was not reported, administered on 19-OCT-2022 for covid-19 prophylaxis which was associated with revaccination with different covid-19 vaccine (Dose number in series 3).   On an unspecified date, the patient experienced confirmed covid-19 infection (Dose number in series 3) and had confirmed clinical vaccination failure (Dose number in series 1). The patient started taking treatment with Non-company suspect drug Paxlovid, (nirmatrelvir/ritonavir) (form of admin, route of admin, batch number and expiry date were not reported) dose and frequency were not reported, (300-100 mg Pack (EUA)) from 14-JAN-2023 to 19-JAN-2023 for treatment of covid-19. On 14-JAN-2023 at 18.00, the patient had bad taste (like bile in throat) everyday during treatment with dizziness, daily Diarrhea 2 times, body aches first 2 days. On 19-JAN-2023, morning, patient took fifth dose of Paxlovid and on 22-JAN-2023, morning, Laboratory data included: COVID-19 virus test Negative. The patient reported that headaches began again on evening of 22-JAN-2023 (Rebound Covid-19) and on 25-JAN-2023, Laboratory data included: COVID-19 virus test Positive. On 28-JAN-2023, Laboratory data included: COVID-19 virus test Positive. The action taken with covid-19 vaccine ad26.cov2.s, elasomeran, elasomeran, and nirmatrelvir/ritonavir was not applicable. The patient was recovering from confirmed covid-19 infection, and the outcome of confirmed clinical vaccination failure and revaccination with different covid-19 vaccine was not reported. This report was serious (Other Medically Important Condition). This report was associated with a product quality complaint: 90000270411.; Sender's Comments: V0: 20230214697-confirmed clinical vaccination failure. The event has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There are other factors more likely to be associated with the event. Specifically: SPECIAL SITUATIONS. Therefore, this event is considered inconsistent with vaccine administration.