Response to a hepatitis B polypeptide vaccine in micelle form in a young adult population.

Polypeptide micelles with relative molecular weights of 25,000 (p25) and 30,000 (gp30) daltons were prepared from native 22-nm hepatitis B surface antigen (HBsAg) particles. This p25/gp30 complex was alum-adsorbed, and three dosage levels (20 micrograms, 4 micrograms, and 0.8 micrograms) were administered at 0, 1, and 6 months to 51 human volunteers. Local and systemic reactions were clinically insignificant, and all vaccinees seroconverted, regardless of dose. As anticipated, antibody responses diminished as the dosage was reduced. Seroconversion rates and geometric mean antibody levels for the 20 micrograms dosage group were significantly better than those observed with a commercial vaccine and were comparable to those achieved after immunization with 40 micrograms of the intact 22-nm particles used to prepare the polypeptides. By 2 weeks, an anti-HBs response was elicited in 80% of the group receiving 20 micrograms of the polypeptide vaccine. This rapid response to immunization may be particularly beneficial for postexposure prophylaxis where the early development of immunity is advantageous.

Viral hepatitis risk in urban emergency medical services personnel.

Houston has large groups of people known to be at high risk for hepatitis B virus (HBV) infection. Emergency medical services (EMS) personnel are continuously exposed to blood from these high-risk individuals. We sought to determine the prevalence of HBV infection in the city's EMS personnel. Of the 350 Houston firefighters assigned to EMS, 344 were surveyed by questionnaire and a blood specimen was obtained. Each sample was assayed by radio-immunoassay or enzyme-linked immunoassay for hepatitis A antibody (anti-HAV), hepatitis B surface antigen (HBsAg), and antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). A history of hepatitis was reported by 19 persons, 17 of whom had serologic evidence of infection with HAV (56%), HBV (26%), or both diseases (11%). The anti-HAV prevalence was 16% (12% in whites and 35% in nonwhites; P less than .001). No correlation was observed with years of occupational exposure. Of the 338 personnel evaluated for HBV seromarkers (six HBsAg-vaccinated subjects were excluded), 13% were positive; 0.6% had an active infection as determined by the presence of both HBsAg and anti-HBc; 6.8% were both anti-HBs and anti-HBc positive; 0.9% were positive for anti-HBc alone; and 4.7% of the sera contained only anti-HBs (all with geometric mean antibody levels of less than or equal to 13 mlU/mL). The 28 individuals (8.3%) whose sera contained anti-HBc were classified as cases of previous or concurrent HBV infection. A strong correlation (P less than .004) was observed between HBV infection and years of work exposure in EMS regardless of job description (paramedic versus emergency medical technician).(ABSTRACT TRUNCATED AT 250 WORDS)

Normal immune response to hepatitis B vaccine in patients with Down's syndrome. A basis for immunization guidelines.

Institutionalized patients with Down's syndrome (DS) are uniquely predisposed to develop chronic hepatitis B infection following exposure. Therefore vaccination is particularly warranted, but there have been concerns that these individuals may react suboptimally. We examined the immune responses of 62 institutionalized patients with DS to 20 and 40 micrograms of hepatitis B vaccine inactivated (Heptavax-B) over one year. The subjects were matched by weight, age, and sex. Seroconversion rates and levels of antibodies to hepatitis B surface antigen (anti-HBs) were comparable to those found in a normal population and were higher than those found in immunocompromised patients undergoing hemodialysis. The anti-HBs levels were consistently higher in the 40-micrograms vaccine group. In patients with DS who were over 30 years old, age was a significant factor in predicting anti-HBs responses. Conversely, in younger subjects, weight was negatively correlated with anti-HBs levels. These data clearly indicate that patients with DS respond normally to hepatitis B surface antigen vaccination and need not be considered a special group when guidelines for vaccination are recommended.

Hepatitis B vaccine: immune responses in children from families with an HBsAg carrier.

A 16 microgram dose of HBsAg prepared by the National Institute of Allergy and Infectious Diseases was administered to 71 children, 18 months to 16 years old. The frequency of seroconversion reached 59% (range: 50-78%) at two weeks following the first dose of vaccine and approached 100% one month after the second dose. There were virtually no side effects. Children less than three years of age developed significantly greater anti-HBs responses than did older children or adults. This appears to be related to the greater dose in microgram kg-1 administered to these children. Anti-HBs responses (mIU ml-1) to the vaccine by the Oriental participants were lower at each sampling interval. Our data suggest that prolonging the third dose of vaccine past six months (e.g. to 12 months) may not significantly alter the eventual antibody levels attained by the vaccinees, but may result in suboptimal protection between the second and third dose in some of them.