Vaccines represent the most successful and sustainable tactic to prevent and counteract infection. A vaccine, typically containing one or several antigens from or similar to a disease-causing microorganism, generally improves immunity to a particular disease upon administration by inducing specific immune responses. Despite the fact that the achievement of appropriate immunization coverage for routine vaccines is a priority for health authorities worldwide, vaccination delays or missed opportunities for immunization are common in children with chronic diseases. The main aim of this cross-sectional study was to evaluate immunization coverage and the timeliness of vaccination in children suffering from 3 different rare genetic diseases. Genetic diseases include allergies, asthma, anaphylaxis, autism, diabetes and other neurological and autoimmune diseases. Some genetic disorders are inherited from the parents, while other genetic diseases are caused by acquired changes or mutations in a preexisting gene or group of genes. Mutations can occur either randomly or due to some environmental exposure.