Vaccination strategies for transplantation in Japan (solid organ transplantation and hematopoietic stem cell transplantation).

The management of infectious diseases in immunocompromised patients represents a critical component of managing severe and refractory conditions, with early diagnosis and prompt therapeutic intervention serving as fundamental principles. Vaccine-preventable disease (VPD) management is equally essential. From a health economics perspective, this approach is pivotal in preventing potentially intractable scenarios. This article reviews immunization strategies in adult patients undergoing solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) in Japan, two distinct categories of immunocompromised individuals. Although many recommended vaccines overlap between these groups, the timing and significance of vaccination prophylaxis differ. Patients who undergo SOT remain immunocompromised long-term, whereas those who have received HSCT experience a period of immune reconstitution following the cessation of immunosuppressive therapy. Additionally, numerous recommended vaccinations must be completed within a defined timeframe, and their management is more complex than that for immunocompetent individuals. Recently, several new vaccines, such as those for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), recombinant zoster, pneumococcal (Pneumococcal conjugate vaccine (PCV)15, 20, 21), and Respiratory syncytial virus (RSV), have been introduced. Recommended vaccination guidance varies across countries, combining established and new information, although some updates may not yet be incorporated. This article provides an overview of current vaccination guidance for SOT and HSCT recipients, highlighting country-specific issues in Japan as well as common challenges faced globally, and proposes optimal strategies for future vaccination policies in Japan.