Prospective Cohort-study for the Investigation of the Vac-cine-induced Immune Response After Vaccination Against RESPiratory Viral Infections in Immunocompromised Pa-tients With or Without Haemato-ONcological diseaSEs

Respiratory virus infections are a significant cause of morbidity and mortality, partic-ularly among immunocompromised patients. These infections are caused by a varie-ty of viral pathogens, including influenza viruses, respiratory syncytial virus (RSV), parainfluenza viruses, adenoviruses, rhinoviruses, and coronaviruses, among oth-ers. In the general population, these infections typically result in self-limiting ill-nesses; however, in individuals with compromised immune systems, such as those undergoing chemotherapy, organ transplant recipients, patients with haematological malignancies, and those with HIV, the consequences can be severe and often life-threatening. For example, patients with haematological and oncological diseases are at elevated risk for severe morbidity and mortality by influenza infections. Com-pared to influenza-associated hospitalization rates in the general population (37.9 per 100,000 person-years for persons age 50 to 64 years)1 patients with cancer were hospitalized at a rate of 219 per 100,000 person-years for patients younger than 65 years.

The immune system plays a crucial role in defending against viral pathogens. Im-munocompromised patients, due to either primary immune deficiencies or second-ary immunosuppression (e.g., from immunosuppressive therapies), have impaired immune responses that hinder the effective clearance of viral infections. This im-pairment can lead to prolonged viral shedding, increased risk of secondary bacterial infections, and more severe disease manifestations, including acute respiratory dis-tress syndrome (ARDS) and multi-organ failure. The management of respiratory vi-rus infections in immunocompromised patients requires a multidisciplinary ap-proach. Prophylactic measures, including vaccination and the use of antiviral prophylaxis, are crucial in reducing the incidence of these infections.

Given the significant impact of respiratory virus infections on immunocompromised patients, ongoing research is crucial to improve preventive strategies. This research includes studies on viral pathophysiology, host immune responses, and the devel-opment of optimal vaccination schedules. The emergence of new viral pathogens, such as SARS-CoV-2, underscores the importance of surveillance and prepared-ness in this vulnerable population.

Respiratory virus infections represent a major health concern for immunocompro-mised patients, necessitating comprehensive and specialised care. Continued ad-vancements in diagnostics, therapeutics, and preventive measures are vital to miti-gate the impact of these infections and improve the quality of life and survival of immunocompromised individuals.

The management of respiratory virus infections in immunocompromised patients requires a multidisciplinary approach and prophylactic measures, including vaccina-tion, to reduce the incidence and severity of these infections. However, the efficacy of vaccination is often suboptimal in immunocompromised individuals and not well assessed in clinical trials.