REVACCINATION WITH DIFFERENT COVID-19 VACCINE; CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; This spontaneous report received from a patient via other manufacturer (Pfizer) concerned a patient of unspecified age, sex, race, and ethnicity. The patient's weight, height, and medical history were not reported. The patient received covid-19 vaccine ad26.cov2.s (dose number in series 1) (suspension for injection, route of admin, batch number and expiry date were not reported) dose, 1 total first dose administered on the left arm on 05-APR-2021 for covid-19 prophylaxis. The batch number was not reported. The Company is unable to perform follow-up to request batch/lot numbers. No concomitant medications were reported. The patient received 2 doses with non-company suspect vaccine Moderna/Spikevax (elasomeran) (dose number in series 2), (form of admin, route of admin, batch number and expiry date were not reported) dose was not reported, second dose administered on the left arm on 11-APR-2022 and (form of admin, route of admin, batch number and expiry date were not reported) dose was not reported, third dose administered on the left arm on the 10-OCT-2022 for covid-19 prophylaxis. It was unknown whether the patient had any adverse events following two doses of elasomeran (dose number in series 2). The patient also received non-company suspect vaccine Pfizer (tozinameran) (dose number in series 3) (form of admin, route of admin, batch number and expiry date were not reported) dose was not reported, fourth dose administered on the left arm on 10-SEP-2022 for covid-19 prophylaxis. It was unknown whether patient had any adverse events following vaccination with tozinameran (dose number in series 3). The patient received another dose of non-company suspect vaccine Pfizer (tozinameran) (dose number in series 4) (form of admin, route of admin, batch number and expiry date were not reported) dose was not reported, fifth dose administered on the left arm on 09-APR-2023 for covid-19 prophylaxis which was revaccination with different covid-19 vaccine (dose number in series 4). On an unspecified date in 2023, the patient experienced covid-19 infection (confirmed covid-19 infection) (dose number in series 4) which led to confirmed clinical vaccination failure (dose number in series 1) and received non-company treatment drug Paxlovid (nirmatrelvir/ritonavir) from 30-AUG-2023 to 04-SEP-2023 for covid-19 treatment. After finishing 5 days prescription of Paxlovid patient tested negative until on 07-SEP-2023, the patient again underwent COVID-19 virus test and tested positive.  The action taken with covid-19 vaccine ad26.cov2.s, elasomeran, tozinameran, and tozinameran was not applicable. The patient had not recovered from confirmed covid-19 infection, and the outcome of revaccination with different covid-19 vaccine and confirmed clinical vaccination failure was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0: 20230930531-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.