SUSPECTED IMMUNOLOGICAL VACCINE FAILURE; This solicited report received from literature:Response to SARS-CoV-2 vaccination in patients after hematopoietic cell transplantation and CAR T-cell therapy. Jansen COVID-19. This report concerned multiple patients (two patients) of unspecified age, sex, race and ethnicity. The objective of this study was to describe, response to SARS-CoV-2 vaccination in patients after hematopoietic cell transplantation and chimeric antigen receptor (CAR) T-cell therapy. The patient's height, and weight were not reported. The patient's concurrent conditions included: haematological malignancy. The patients initiated treatment with Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin, and batch number were not reported and expiry was unknown) frequency time 1 total, dose, start therapy date were not reported for Prophylactic vaccination. The batch number was not reported and has been requested. Concomitant therapy included hematopoietic cell transplantation (HCT) and chimeric antigen receptor (CAR) T- cell therapy. On an unspecified date, the patients underwent SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antibody test, which was negative. The blood samples were tested using an enzyme immunoassay (EUROIMMUN) that tests for antibodies to the S1 domain of the SARS-CoV-2 spike protein (suspected immunological vaccine failure).  The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The outcome of suspected immunological vaccine failure was not reported. The reporter provided no causality assessment. Company causality between Covid-19 vaccine ad26.cov2.s, and suspected immunological vaccine failure was not related.  The authors concluded, the findings of low antispike antibodies in patients undergone HCT and receiving CAR T-cell therapy after COVID-19 vaccination suggest that such patients might remain at high risk of COVID-19 infection despite vaccination. The results observed in this study underscore the importance of masking, social distancing, and household vaccination for patients undergoing HCT and receiving CAR T-cell therapy, even after vaccination. Additional studies examining the wider immune repertoire with characterization of memory B- and T-cell immune responses over time and neutralizing antibody capacity are needed to better assess immunological response. In patients who do not achieve optimal immune response, studies examining the role of booster doses or revaccination are needed. This report was serious (Other Medically Important Condition). This report is associated with product quality complaint number 90000197786. This case, from the same reporter is linked to 20210948620, 20210732170, 20210302465, 20210102329, 20210415497, 20191102087, 20210441941, 20210359826, 20210317981, 20200115362 and 20191102112.; Sender's Comments: V0:20211021158-covid-19 vaccine ad26.cov2.s-suspected immunological vaccine failure. This event(s) is considered not related. The event(s) 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(s) than the drug. Specifically: MEDICAL HISTORY, SPECIAL SITUATIONS