EARLY AND LATE RESPONSE TO HEPATITIS-B VACCINE IN HIGH-RISK CHILEAN SUBJECTS

Background: Hepatitis B vaccine has demonstrated to be very effective and safe preventing hepatitis B virus infection. Long term protection induced by hepatitis B vaccination depends on the initial immune respo nse and the declining rate of anti-HBs titers. Aim. To investigate ear ly and late response to hepatitis B vaccine in a sample of high risk C hilean population. Material and methods: Thirty one subjects (20 relat ives of hepatitis B chronic carriers, 10 health service workers and on e HIV seropositive) were vaccinated with a plasma derivated hepatitis B vaccine. Early and late response were estimated by anti-HBs titers. Results: Twenty eight subjects (90%) produced protective titers of ant i-HBs after 2 months from the third dose of vaccine (early response), and they remained at these levels in 75% of vaccinated individuals aft er three years (late response). All the subjects without protective ti ters after the three year follow up had produced anti-HBs levels lower than 300 UI at the early response. Hepatitis B vaccination was not as sociated with significant side effects. Conclusions: This experience c onfirms that hepatitis B vaccine is safe and effective inducing immuni ty in high risk subjects, Our data suggest that the early response to hepatitis B vaccine is able to identify those subjects requiring close r surveillance for boosters.