CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; This spontaneous report received from a patient via other manufacturer Pfizer Inc. concerned a 43 year old male. Initial information was processed along with follow up information received on 26-APR-2022. The patient's height, and weight were not reported. The patient's past medical history included: Patient had a history of sporadic abnormal liver enzyme tests, but no specific illness or diagnosis related to that and concurrent conditions included: allergy. Laboratory data (dates unspecified) included: Hepatic enzyme (NR: not provided) Abnormal.  The patient previously received covid-19 vaccine ad26.cov2.s (dose number in series 1) (suspension for injection, route of admin not reported, batch number: 043A21A, and expiry: unknown) dose was not reported, 1 total administered on 09-APR-2021 at 14:00 to left arm for prophylactic vaccination. Age at time of vaccination 42 years old. No concomitant medications were reported. The patient received Spikevax (elasomeran) (dose number in series 2) (form of admin, route of admin was not reported, and batch number: 0762CA , expiry: unknown) dose was not reported administered on 23-OCT-2021 at 13:15 to left arm for prophylactic vaccination.  On 31-MAR-2022, the patient tested positive for Covid-19 (confirmed Covid-19 infection) (dose number in series 2) and had confirmed clinical vaccination failure (dose number in series 1). Laboratory data included: COVID-19 virus test (NR: not provided) positive. Patient was treated with Paxlovid (Nirmatrelvir/ritonavir) on day 1 of being tested positive (31-MAR-2022) for treatment of covid-19 and completed the course as prescribed within 5 days (until 05-APR-2022). Patient had not taken any other medications within 2 weeks of starting Covid-19 treatment. On 07-APR-2022, after about 8 days of very very mild symptoms, the patient tested negative for Covid-19. Laboratory data included: COVID-19 virus test (NR: not provided) negative. The patient performed multiple tests on multiple days and tested negative. On 13-APR-2022 at 18:30, roughly 6 days later, patient began to experience cold symptoms and took a rapid test for Covid-19 which unexpectedly turned out to be positive. Laboratory data included: COVID-19 rapid POC test (NR: not provided) positive. At the time of report, patient was 5 days into the second episode of Covid-19 and still tested positive with mild to moderate symptoms. Laboratory data (dates unspecified) included: COVID-19 virus test (NR: not provided) positive. As per the patient, a new infection seemed highly unlikely but Paxlovid could have subdued the infection and it had resurged again. The patient was not hospitalized.  The action taken with covid-19 vaccine ad26.cov2.s, and elasomeran was not applicable. The patient had not recovered from confirmed covid-19 infection, and the outcome of confirmed clinical vaccination failure was not reported. This report was serious (Other Medically Important Condition). This case was associated with a product quality complaint: 90000228222.; Sender's Comments: V0: 20220449687 -COVID-19 VACCINE AD26.COV2.S- confirmed clinical vaccination failure. This event is considered not related. 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 than the drug. Specifically: SPECIAL SITUATIONS.