Although individually rare, inborn errors of immunity (IEI), as a group, affect a significant number of people worldwide and are mostly underdiagnosed. Among many severe challenges brought about by these generally genetic disorders are issues pertaining to vaccination. With some exceptions (i.e., IEI with mild or strictly limited impairment of immune system function), disorders of this group preclude the use of live vaccines due to a considerable risk of life-threatening vaccine-strain infections. This makes early diagnosis even more important, since many IEI may exhibit few or no clinical signs at the age when the administration of some live vaccines is recommended or mandated by national immunization programs. Some countries have therefore instituted newborn screening for certain IEI, with encouraging results. Non-live vaccines, on the other hand, are generally well tolerated by persons affected by IEI, no less than by unaffected persons, and thus the diagnosis of IEI does not constitute a contraindication for non-live vaccines. However, accumulated published experience indicates that in practice, contrary to valid recommendations and basic facts regarding the underlying principles of immunization, non-live vaccine administration is often delayed in IEI, or even omitted altogether due to physicians’ or parents’/caregivers’ concerns. Because of their obvious vulnerability, people with IEI may also require protection by additional vaccines that are not part of the routine immunization schedule. In view of these challenges and complexities, a specialist evaluation by an experienced immunologist may be warranted in many instances. Equally important, however, is effective communication regarding vaccination across the boundaries of medical disciplines, as well as between the medical/healthcare community and the general public.
