CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; REVACCINATION WITH DIFFERENT COVID-19 VACCINE; This spontaneous report received from a patient through other manufacturer (Pfizer Inc.) concerned a 55 year old female. Initial information was processed along with the additional information received on 20-MAR-2023. The patient's height, and weight were not reported. The patient's concurrent conditions included: allergy, and other pre-existing medical conditions included: The patient was not pregnant at the time of vaccination and had no history of past drug. The patient stated she was taking other medication or products within 2 weeks of starting covid-19 treatment (Paxlovid). The patient received first dose of covid-19 vaccine ad26.cov2.s (Dose number in series 1) (suspension for injection, route of admin not reported, batch number: 1808978 expiry: UNKNOWN) dose was not reported, single dose 1 total was administered on 03-APR-2021 for covid-19 prophylaxis. Age at time of vaccination 54 years old. No concomitant medications were reported.  The patient received second dose of non-company suspect vaccine Moderna covid-19 vaccine (elasomeran) (Dose number in series 2) (form of admin, route of admin not reported, batch number: 939905 expiry: UNKNOWN) dose was not reported, administered on 27-OCT-2021 for covid-19 prophylaxis.  It was unknown whether patient had any adverse events following vaccination with Moderna covid-19 vaccine (elasomeran) (Dose number in series 2). The patient received third dose of non-company suspect vaccine Pfizer biontech covid-19 vaccine (tozinameran) (Dose number in series 3) (form of admin, route of admin not reported, batch number: FK9894 expiry: UNKNOWN) dose was not reported, administered on 02-APR-2022 for covid-19 prophylaxis. It was unknown whether patient had any adverse events following vaccination with Pfizer biontech covid-19 vaccine (tozinameran) (Dose number in series 3). The patient received fourth dose of non-company suspect vaccine Pfizer biontech covid-19 vaccine (tozinameran) (Dose number in series 4) (form of admin, route of admin not reported, batch number: GH9702 expiry: UNKNOWN) dose was not reported, administered on 17-SEP-2022 for covid-19 prophylaxis which was associated with revaccination with different covid-19 vaccine (Dose number in series 4). On an unspecified date, the patient experienced confirmed covid-19 infection (Dose number in series 4) 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 from 26-FEB-2023 to 03-MAR-2023 for treatment of covid-19. On 26-FEB-2023, Laboratory data included: COVID-19 virus test Positive. On 02-MAR-2023, Laboratory data included: COVID-19 virus test Negative and again on 03-MAR-2023, Laboratory data included: COVID-19 virus test Negative.  On 07-MAR-2023, She was tested negative for COVID-19 virus test . On 08-MAR-2023, symptoms had returned again (covid-19 rebound infection) and on same day COVID-19 virus test was Positive.  The action taken with covid-19 vaccine ad26.cov2.s, elasomeran, tozinameran, and tozinameran was not applicable; and action taken with nirmatrelvir/ritonavir was not reported. 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 90000275592.; Sender's Comments: V0: 20230342273-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.