Vaccination of immunocompromised patients: immunological principles, clinical indications and safety protocols

Vaccination of immunocompromised patients is an essential component of personalized preventive medicine, located at the intersection of safety, efficacy and the underlying immune defect. This paper summarizes the immunological basis of post-vaccination responses, the differences between inactivated and live attenuated vaccines, and the clinical implications of these differences in the main primary and secondary immunodeficiencies. It highlights the multiple roles of vaccination: preventive, diagnostic and prognostic, including the use of post-vaccination responses to assess lymphocyte function and guide immunoglobulin replacement therapy. The paper also discusses indirect protection strategies through vaccinating close contacts, the optimal timing of vaccination in relation to transplantation or immunomodulatory therapies, and the situations in which live vaccines are contraindicated. The central conclusion is that vaccination in immunocompromised patients should not be applied uniformly, but individualized according to the type and severity of immune deficiency, concomitant treatments and the epidemiological context, with the aim of maximizing protection and minimizing clinical risk.