Adult Vaccination and Preventive Immunization in High-Risk Populations: An Updated Clinical Review

Vaccination remains one of the most effective public health interventions for preventing infectious diseases and reducing morbidity and mortality. Adult immunization is particularly important in older adults, individuals with chronic diseases, residents of long-term care facilities, and immunocompromised populations, who are at increased risk of severe infections. This narrative review summarizes current recommendations from major public health organizations, including the WHO, ECDC, and CDC, with emphasis on adult and high-risk populations. Key vaccine platforms are discussed, including influenza, pneumococcal, mRNA-based COVID19, RSV, herpes zoster, and hepatitis B vaccines. The review also highlights the role of immunosenescence in reduced vaccine responsiveness and discusses emerging applications of mRNA technology in oncology. Overall, targeted immunization strategies remain essential for reducing disease burden and improving health outcomes.

Keywords: Adult Vaccination, Immunization, High-Risk Populations, Immunosenescence, Influenza Vaccine, Pneumococcal Vaccine, mRNA Vaccines.