Intradermal vaccination of adults with three low doses (2 µg) of recombinant hepatitis B vaccine. I. Seroconversion rate and adverse effects

A total of 250 dentists (53.6% men and 46.4% women), with a mean age of 35.1 ± 9.8 years, were submitted toserological tests for the diagnosis of hepatitis B (HB) – HBsAg, anti-HBs, anti-HBc, HBeAg, and anti-HBe – using aradioimmunoassay. One or more of these markers were detected in 78 individuals (31.2%) who were excluded fromthe group to be vaccinated. Of the 172 HB-susceptible individuals, 135 (78.5%) responded to the call and wereintradermally injected with three 2 µg doses of the Belgian HB recombinant vaccine, applied at an interval of onemonth between the 1st and 2nd dose and of five months between the 2nd and 3rd dose. A new determination of HBmarkers carried out 50 days after the 3rd dose showed that 110 (81.5%) individuals had become anti-HBs positive(65.5% good responders and 34.5% poor responders). Mean serum anti-HBs titer of these 110 dentists was 42.4 US/N, similar in both sexes. The adverse effects analyzed in 106 dentists were: (a) local: pain (12.3%), burningsensation (14.1%), pruritus (25.5%), erythema (28.3%), local heat (18.9%), and a hypochromic spot (32.1%); (b)systemic (4.7%): discomfort in two patients, and fever, anorexia, and asthenia in one patient each. Intradermaladministration of a fourth 2 µg vaccine dose to 39 dentists (poor or non-responders) increased the total number ofanti-HBs-positive individuals from 110 (81.5%) to 114 (84.4%), with the number of good responders increasingfrom 72 (65.5%) to 85 (74.6%). We conclude that the Belgian recombinant vaccine applied in the scheme used hereinduces a high rate of seroconversion and causes only mild and transitory adverse effects.