BackgroundManaging SARS‐CoV‐2 infection in frail and immunosuppressed patients still represents an open challenge, but, starting from the phase 3 PROVENT study, prophylaxis with tixagevimab‐cilgavimab has improved the approach in this category of patients, guaranteeing a better outcome and inferior mortality. Real‐life data in a heterogeneous cohort are few.MethodsThe aim of this study is to evaluate the benefit of prophylaxis with tixagevimab‐cilgavimab in a cohort of 202 patients affected by different hematological diseases (lymphoproliferative, myeloproliferative, autoimmune, patients recently receiving a bone marrow transplant), active (with ongoing treatment), or in watch‐and‐wait strategy, followed in our center, during a median follow‐up of 249 (45‐325) days.ResultsAn incidence of 44 breakthrough infections (21.8%) is reported, with no treatment‐related adverse effects. Age ≥70 years, ongoing treatment (above all with monoclonal antibodies), baseline lymphoproliferative disorders, and prior virus exposure are identified as risk factors related to subsequent infection (p < 0.05). Moreover, the incidence is higher in low/nonresponse to prior vaccination (p = .002). Patients treated with tixagevimab‐cilgavimab had a mild course of the infection and a reduction of the duration compared with preprophylaxis infection (11 vs. 15 days, p < .001). The concurrent treatment with anti‐CD20 monoclonal antibodies and B–non‐Hodgkin lymphoma still confers a higher duration of infection despite prophylaxis. No deaths attributable to the infection occurred.ConclusionProphylaxis treatment seems to be a valid and safe strategy, although not preventing breakthrough infection, but the severe complications associated with the infection and the possible delays in administering lifesaving therapies from long positivity.