The hypothesis of systemic disease flare up or onset triggered by vaccination cannot be confirmed by the analysis of data from the literature. In immune deficiency of any cause, immunization is of great interest to avoid preventable infectious diseases but the risk of adverse events and suboptimal immunologic responses has to be considered. For live, attenuated vaccines the main risks are postimmunization complications, specially in persons severely immunocompromised. For killed or inactivated vaccines there are no contraindications, but the immune response is reduced leading to consider higher vaccine doses or more frequent boosters. However the response to such modifications of vaccine schedules has not been systematically evaluated and firm recommendations cannot be made at this time. In addition, in HIV infection, the effect of vaccination on viral replication has to be considered. In developing countries some live vaccines are still recommended in HIV+ children because of the prevalence of the target-diseases (measles, poliomyelitis, tuberculosis...) and the rarity of complications.