CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; REVACCINATION WITH DIFFERENT COVID-19 VACCINE; This spontaneous report received from a patient via another pharmaceutical company (Pfizer) concerned a 55 year old female. Initial information was processed along with the additional information received on 28-APR-2023. The patient's height, and weight were not reported. The patient's concurrent conditions included: microscopic colitis, and unspecified drug allergy. Patient was not pregnant at time of reporting. The patient received covid-19 vaccine ad26.cov2.s (Dose number in series 1) (suspension for injection, route of admin not reported, batch number: 1805018 expiry: unknown) dose was not reported, 1 total was administered to left arm on 06-MAR-2021 for covid-19 prophylaxis. Age at time of vaccination 53 years old.  The patient additionally received non-company suspect vaccine Moderna covid-19 vaccine (elasomeran) (Dose number in series 2) (form of admin, route of admin were not reported, batch number: 939905 expiry: unknown) dose was not reported, administered at left arm 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 additionally received non-company suspect vaccine Moderna covid-19 vaccine (elasomeran) (Dose number in series 3) (form of admin, route of admin were not reported, batch number: 56A22A expiry: unknown) dose was not reported, administered at left arm on 27-APR-2022 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 3). The patient additionally received non-company suspect vaccine Moderna covid-19 vaccine (elasomeran) (Dose number in series 4) (form of admin, route of admin were not reported, batch number: 57F22A expiry: unknown) dose was not reported, administered at left arm on 12-OCT-2022 for covid-19 prophylaxis which was revaccination with different covid-19 vaccine (Dose number in series 4). Concomitant medications included ondansetron, Tylenol (paracetamol), and Ambien (zolpidem tartrate).  On unspecified date in APR-2023, the patient experienced covid-19 infection (confirmed covid-19 infection) (Dose number in series 4) and received non-company suspect drug Paxlovid (nirmatrelvir/ritonavir) (form of admin, route of admin, batch number and expiry were not reported) dose and frequency were not reported from 10-APR-2023 to 14-APR-2023 for covid-19 treatment. On 19-APR-2023 about two to three days after testing negative patient started to feel worse again and had cold symptoms, fatigue, lots of phlegm in throat, trying to catch breath after just moving about the house. Patient tested positive one week after testing negative for the first time which led to confirmed clinical vaccination failure (Dose number in series 1). The action taken with covid-19 vaccine ad26.cov2.s, elasomeran (Dose number in series 2), elasomeran (Dose number in series 3), and elasomeran (Dose number in series 4) 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 product quality complaint: 90000280781.; Sender's Comments: V0: 20230462132-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.