CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; REVACCINATION WITH DIFFERENT COVID-19 VACCINE; This spontaneous report received from a patient via other manufacturer (Pfizer) concerned a patient of unspecified age and sex. Initial information was processed along with additional information on 16-FEB-2023. The patient's height, and weight were not reported. The patient's concurrent conditions included: drug allergy (Probably sulfa drugs), and other pre-existing medical conditions included: Patient had no relevant medical history and concurrent conditions. The patient was not taking any other medications/products within 2 weeks of starting COVID-19 treatment. The patient received covid-19 vaccine ad26.cov2.s (dose number in series 1) (suspension for injection, route of admin not reported, batch number: 205A21A expiry: UNKNOWN) dose was not reported, 1 total, administered on 11-APR-2021 in left arm for covid-19 prophylaxis. No concomitant medications were reported. The patient received non-company suspect vaccine included: Moderna covid-19 vaccine (elasomeran) (dose number in series 2) (form of admin, and route of admin was not reported, batch number: 014F21A expiry: UNKNOWN) dose was not reported, administered on 02-NOV-2021 in left arm for covid-19 prophylaxis. It was unknown whether patient had any adverse event following vaccination with Moderna covid-19 vaccine (elasomeran) (dose number in series 2). The patient received non-company suspect vaccine included: Pfizer biontech covid-19 vaccine (tozinameran) (dose number in series 3) (form of admin, and route of admin was not reported, batch number: FM9992 expiry: UNKNOWN), dose, start therapy date were not reported, administered in left arm for covid-19 prophylaxis. It was unknown whether patient had any adverse event following vaccination with Pfizer biontech covid-19 vaccine (tozinameran) (dose number in series 3). The patient additionally received non-company suspect vaccine included: Moderna covid-19 vaccine (elasomeran) (dose number in series 4) (form of admin, and route of admin was not reported, batch number: 053D22A expiry: UNKNOWN) dose was not reported, administered on 15-OCT-2022 in left arm for covid-19 prophylaxis which was revaccination with different covid-19 vaccine (dose number in series 4). On an unspecified date, the patient experienced covid-19 infection (dose number in series 4) for which patient received non-company suspect drug included: Paxlovid (nirmatrelvir/ritonavir) (pill, route of admin was not reported, batch number: 1923797A expiry: UNKNOWN) dose was not reported, 1 time every 0.5 days (5 days-3 pills-2 per day) from 25-JAN-2023 to 30-JAN-2023 for covid-19 treatment.  On 01-FEB-2023, patient tested negative or almost negative. Laboratory data included: COVID-19 virus test Negative. On 03-FEB-2023, two days later, the patient tested strongly positive (home tests) and symptoms returned which led to confirmed covid-19 infection (dose number in series 4) and confirmed clinical vaccination failure (dose number in series 1). Laboratory data included: COVID-19 virus test Positive. The action taken with covid-19 vaccine ad26.cov2.s, elasomeran, tozinameran, and elasomeran was not applicable; and action taken with nirmatrelvir/ritonavir was not reported. The patient had not recovered 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: 90000271622.; Sender's Comments: V0: 20230236157-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.