CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; REVACCINATION WITH DIFFERENT COVID-19 VACCINE; This spontaneous report received from a consumer via other manufacturer concerned a patient of an unspecified age, sex, race and ethnicity. Initial information was processed along with the additional information received on 03-APR-2023. The patient's height, and weight were not reported. The patient's concurrent conditions included: drug allergy (unspecified). The patient received covid-19 vaccine ad26.cov2.s (Dose number in series 1) (suspension for injection, route of admin not reported, batch number: Unknown, expiry: unknown) dose was not reported, 1 total was administered on 07-APR-2021 to right arm for covid-19 prophylaxis. The batch number was not reported. The Company is unable to perform follow-up to request batch/lot numbers. Concomitant medications included dextromethorphan hydrobromide/guaifenesin (Mucinex DM 12-hour tablets), and ibuprofen/pseudoephedrine hydrochloride (Advil Cold and Sinus gel caps). 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: Unknown, expiry: unknown) dose was not reported, administered on 25-OCT-2021 to right arm 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 Moderna covid-19 vaccine (elasomeran) (Dose number in series 3) (form of admin, route of admin not reported, batch number: Unknown, expiry: unknown) dose was not reported, administered on 07-SEP-2022 to right arm for covid-19 prophylaxis which was associated with revaccination with different covid-19 vaccine (Dose number in series 3). On an unspecified date in 2023, the patient experienced covid-19 infection (coded as confirmed covid-19 infection) (Dose number in series 3) and had started 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 14-MAR-2023 to 19-MAR-2023 for covid-19 treatment. On 19-MAR-2023, the patient was tested negative for COVID-19 virus test.  On 24-MAR-2023, the patient had resurgence of symptoms (cough, congestion and fever) and had not received any treatment nor hospitalized (Dose number in series 3). On 26-MAR-2023 (after 7 days of negative test), the patient tested positive with home rapid test (COVID-19 rapid POC test) which resulted 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), and elasomeran (Dose number in series 3) 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: 90000277525.; Sender's Comments: V0: 20230378157-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.