RESUMO
The efficacy of a heat inactivated hepatitis B virus vaccine, containing 3 micrograms hepatitis B surface antigen (HBsAg), was studied in a high risk group of 800 susceptible homosexual men by a randomised placebo controlled double blind trial. At the trial end point (21.5 months), 17 hepatitis B virus infections had occurred in vaccinated subjects (attack rate 4.8%) and 56 in subjects receiving a placebo (attack rate 23.8%). This reduction in the incidence of hepatitis B virus infections in vaccinated subjects was highly significant (p less than 0.0001). Two months after the first injection 72.3% of the vaccinated subjects had formed antibodies against hepatitis B surface antigen, and this percentage increased to 89% at four months. Maximum anti-HBs titres were reached five months after the first vaccination, the geometric mean titre being 107.6 mIU. Even vaccinated subjects with a low antibody response (greater than or equal to 1 and less than 10 mIU) were found to be protected from HBsAg-positive infections. The vaccine had no serious side effects.
Assuntos
Vírus da Hepatite B/imunologia , Hepatite B/prevenção & controle , Homossexualidade , Vacinas Virais/uso terapêutico , Adulto , Ensaios Clínicos como Assunto , Método Duplo-Cego , Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Temperatura Alta , Humanos , Masculino , Distribuição Aleatória , Fatores de Tempo , Vacinas AtenuadasRESUMO
The efficacy of a heat-inactivated hepatitis B virus (HBV) vaccine, containing 3 micrograms-HBsAg, was studied among a group of 800 susceptible homosexual men. The trial was conducted randomized, placebo-controlled and double blind. At the trial end point (21.5 months) the attack-rate for all HBV infections together was 4.8% among vaccinees and 23.8% among the placebos (p less than 0.0001). Four months after the first injection 89% of the vaccinees had formed anti-HBs and this percentage declined only slightly during the follow-up period. Maximum titers were reached 5 months after the first vaccination. None of the vaccinees who responded to the vaccine with anti-HBs greater than or equal to 1 mIU/ml developed a HBsAg positive infection. The vaccine had no serious side-effects.
