Abstract : The treatment of moderate to severe psoriasis relies currently on the use of IL17 and IL23 antagonists. These biological treatments are highly efficacious with an excellent long-term safety profile. Despite the targeted actions of these agents, they are associated with a mild degree of immunosuppression, potentially leading to the reactivation of preexisting infectious diseases, or to an increased susceptibility to infectious diseases or an increased severity and duration of an infectious disease. Hence psoriasis patients receiving biologics must be counseled on recommended vaccinations before initiating a biological therapy or during a biological treatment. In general, for living attenuated vaccinations biologic treatment must be interrupted but for inactivated vaccinations it may be continued. Currently there is no proof that psoriasis patients treated with IL17 or IL23 antagonists present an increased risk for the infections covered by the conventional vaccines and hence the vaccination guidelines should follow the recommendations for the general population.