ANTIBODY-LEVELS IN ETHIOPIAN CHILDREN 5 YEARS AFTER VACCINATION WITH 2 DIFFERENT DOSES OF HEPATITIS-B VACCINE - IS THERE A NEED FOR BOOSTERVACCINE

It was hypothesized that, following effective initial vaccination, a b ooster dose of hepatitis B vaccine will not be necessary in areas of h yperendemicity for hepatitis B virus (HBV) infection. A total of 314 E thiopian children, ranging from two to 14 years old, were alternativel y vaccinated with 10 and 20 mu g hepatitis B vaccine doses, using the initial, one-and six-month schedule. Five years later, 210 of the vacc inees were retested for anti-HBV surface antibody titres. Both 10 and 20 mu g doses of hepatitis B rDNA yeast vaccine were equally immunogen ic and protective against HBV infection for at least five years despit e marked reduction of mean antibody levels and geometric mean titres, with 11% of the vaccinees showing antibodies below the protective leve l. For firm further recommendations a longer follow-up period of vacci nees is suggested.