[Editorial of the "vaccination issue" of KMIL--what have demonstrated Prevenar and Fendrix vaccines].

Immunization against infectious diseases is one of the most effective prevention instruments. Ongoing research has shown that revaccination against viral hepatitis type A and B (VHA and VHB) in healthy immunocompetent individuals is not necessary and that basic VHA and VHB vaccination schedules provide lifelong immunity. In the USA, Prevnar, a 7-valent conjugated pneumococcal vaccine, demonstrated its substantial direct and indirect effects on the incidence of invasive pneumococcal diseases (IPD). As a matter of fact, its introduction led to a dramatic decrease in invasive pneumococcal diseases both in children and, indirectly, also in the senior age cohorts. In addition, lower pneumococci colonisation of the mucosa, constituting this indirect effect, leads to a lower incidence of acute otitis among children up to 2 years of age. The use of Prevenar also decreases the incidence in the population of Streptococcus pneumoniae strains that are resistant to penicillin or erythromycin. The Fendrix is the first vaccine that has received market authorisation in the EU and that contains MPL (Monophosphoryl lipid A) as an adjuvans. It serves for the purpose of immunisation of haemodialysed patients and, in contrast to Engerix B, it creates a faster, more massive and longer immune response. At present, at haemodialysis units, two doses of the Engerix B vaccine (a total of 2 ml and 40 mcg of the HBsAg antigen) are used for basic immunisation that are applied according to a particular schedule-in month 0, 1, 2, and 6. Fendrix is applied in accordance with the same schedule however, only one dose is used. The applied schedule allows maintaining higher antibody titres for longer periods of time than with Engerix B. Thus further revaccination doses are spared for later use, since, in haemodialysed patients, the anti-HBs levels cannot fall under 10 mIU/ml.