Vaccination in Special Pediatric Populations: Immunocompromised, Preterm, and Chronically Ill Children

Immunisation is one of the most effective strategies for preventing childhood morbidity and mortality. However, vaccination in special pediatric populations—including immunocompromised children, preterm infants, and those with chronic illnesses—presents unique challenges. Standard vaccine schedules are designed for healthy children, but immunological immaturity, altered responses, medication-induced immunosuppression, and comorbidities necessitate modified approaches in vulnerable groups. This review synthesises current evidence and guidelines on pediatric immunisation in these special populations. It addresses immune responses in preterm and low-birth-weight infants, vaccination safety and efficacy in children with HIV, cancer, autoimmune disorders, and organ transplants, and considerations for children with chronic conditions such as congenital heart disease, chronic kidney disease, and asthma. Updated recommendations from the WHO, CDC, and IAP are highlighted, along with gaps in coverage, and future directions including tailored vaccine technologies, monoclonal antibody prophylaxis, and digital health solutions for personalised vaccination schedules. While progress has been made in optimising vaccine strategies for high-risk children, significant challenges remain in ensuring equitable access, building parental and provider confidence, and conducting robust clinical trials in vulnerable populations. Strengthening surveillance, improving international consensus guidelines, and leveraging new-generation vaccines will be critical to protecting these children and reducing preventable infectious disease burdens.