Response to an extra dose of hepatitis B vaccine and specific antibody persistence in non-responders to primary immunization

BACKGROUND: In a campaign to vaccinate health care workers, a three-dose schedule (0, 1, and 6 months) and a four-dose schedule (0, 1, 2, and 14 months) with hepatitis B (HB) vaccine were used. After primary immunization 26 subjects vaccinated with the 3-dose schedule and 4 subjects vaccinated with the 4-dose schedule had undetectable anti-HBs titres. METHODS: All these 30 non-responders received an extra dose of the same vaccine 2 months after primary immunization and a booster dose with a yeast-derived vaccine 6 years later. Anti-HBs levels were evaluated 1 month after the extra dose and after the booster dose. RESULTS: One month after the extra dose 26.9% (7 of 26) of the subjects vaccinated with the 3-dose schedule became positive for anti-HBs. Six years later only two of these subjects had detectable anti-HBs. After the booster dose the seven subjects who responded to the extra dose showed an anamnestic type of response, and five additional subjects became positive for anti-HBs. Responders to the extra dose were significantly younger than the non-responders. In the four-dose group only one subject responded to the extra dose, and that subject maintained protective anti-HBs. CONCLUSION: About 25% of non-responders to primary HB vaccination could benefit from an extra dose, and these subjects show an anamnestic type of response to HBs antigen even after 6 years. This response seems to be influenced by age

Risposta ad una extra-dose di vaccino contro l\u2019HBV e durata di anti-HBs in non-responders al primo ciclo vaccinale

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Response to an extra dose of hepatitis B vaccine and specific antibody persistence in non-responders to primary immunization

BACKGROUND: In a campaign to vaccinate health care workers, a three-dose schedule (0, 1, and 6 months) and a four-dose schedule (0, 1, 2, and 14 months) with hepatitis B (HB) vaccine were used. After primary immunization 26 subjects vaccinated with the 3-dose schedule and 4 subjects vaccinated with the 4-dose schedule had undetectable anti-HBs titres. METHODS: All these 30 non-responders received an extra dose of the same vaccine 2 months after primary immunization and a booster dose with a yeast-derived vaccine 6 years later. Anti-HBs levels were evaluated 1 month after the extra dose and after the booster dose. RESULTS: One month after the extra dose 26.9% (7 of 26) of the subjects vaccinated with the 3-dose schedule became positive for anti-HBs. Six years later only two of these subjects had detectable anti-HBs. After the booster dose the seven subjects who responded to the extra dose showed an anamnestic type of response, and five additional subjects became positive for anti-HBs. Responders to the extra dose were significantly younger than the non-responders. In the four-dose group only one subject responded to the extra dose, and that subject maintained protective anti-HBs. CONCLUSION: About 25% of non-responders to primary HB vaccination could benefit from an extra dose, and these subjects show an anamnestic type of response to HBs antigen even after 6 years. This response seems to be influenced by age

Two different dosages of yeast derived recombinant hepatitis B vaccines: A comparison of immunogenicity

The efficacy of a 10 or 20 micrograms antigen load of HB recombinant vaccines is still being debated. A comparison of anti-HBs titres in two groups of healthy subjects vaccinated by the same schedule (0, 1 and 6 months) employing recombinant HB vaccines with different antigen loads, 20 micrograms (group A, 251 subjects) and 10 micrograms (group B, 256 subjects) was carried out. A seroprotection rate of 99.6 and 99.2% was observed for group A and group B, respectively, at the end of primary immunization. No statistically significant difference in seroprotection rate was observed. Group A showed significantly higher GMTs than group B for all age groups and for both sexes except for males above 25 years. The difference was more marked for younger age groups and for the female sex. These data support the higher immunogenicity of vaccine with 20 micrograms antigen load as compared to vaccines with 10 micrograms antigen load

Persistence of anti-HBs antibodies in health care personnel vaccinated with plasma-derived hepatitis B vaccine and response to recombinant DNA HB booster vaccine

Long-term persistence of specific antibodies after primary immunization against HBV infection has been reported. In this study, we evaluated the persistence of anti-HBs in vaccinees 6 years after primary immunization and the response to a booster dose using a recombinant DNA yeast-derived HB vaccine. An 85.4% seroprotection rate was observed after 6 years with a significantly higher seroprotective rate in those subjects who received four doses of vaccine primary immunization as compared with those who received three doses (93.9% versus 67.2%, p < 0.001). One month after receiving the booster dose, 98.6% of the subjects had an anamnestic type of response. The GMTs were found to decrease progressively with increasing age. The antibody levels after booster dose were higher than those attained at the end of primary immunization and reflected the trend seen before the administration of the booster. These results are consistent with the existence of an effective immunological memory in HB vaccine responders. Subjects who received four doses during primary immunization were better seroprotected and had a higher seroprotection rate after the booster dose

Two different dosages of yeast derived recombinant hepatitis B vaccines: A comparison of immunogenicity

The efficacy of a 10 or 20 mu-g antigen load of HB recombinant vaccines is still being debated. A comparison of anti-HBs titres in two groups of healthy subjects vaccinated by the same schedule (0, 1 and 6 months) employing recombinant HB vaccines with different antigen loads, 20 mu-g (group A, 251 subjects) and 10 mu-g (group B, 256 subjects) was carried out. A seroprotection rate of 99.6 and 99.2% was observed for group A and group B, respectively, at the end of primary immunization. No statistically significant difference in seroprotection rate was observed. Group A showed significantly higher GMTs than group B for all age groups and for both sexes except for males above 25 years. The difference was more marked for younger age groups and for the female sex. These data support the higher immunogenicity of vaccine with 20 mu-g antigen load as compared to vaccines with 10 mu-g antigen load

Persistence of anti-HBs antibodies in health care personnel vaccinated with plasma-derived hepatitis B vaccine and response to recombinant DNA HB booster vaccine

Long-term persistence of specific antibodies after primary immunization against HBV infection has been reported. In this study, we evaluated the persistence of anti-HBs in vaccinees 6 years after primary immunization and the response to a booster dose using a recombinant DNA yeast-derived HB vaccine. An 85.4% seroprotection rate was observed after 6 years with a significantly higher seroprotective rate in those subjects who received four doses of vaccine primary immunization as compared with those who received three doses (93.9% versus 67.2%, p < 0.001). One month after receiving the booster dose, 98.6% of the subjects had an anamnestic type of response. The GMTs were found to decrease progressively with increasing age. The antibody levels after booster dose were higher than those attained at the end of primary immunization and reflected the trend seen before the administration of the booster. These results are consistent with the existence of an effective immunological memory in HB vaccine responders. Subjects who received four doses during primary immunization were better seroprotected and had a higher seroprotection rate after the booster dose

Immunity status to polioviruses among non-European union immigrants in Veneto Region (North-East Italy)

Widespread use of poliovirus vaccines has lead to a dramatic decline on the incidence of paralytic poliomyelitis in the Western Hemisphere. In Italy, the use of live attenuated vaccine (OPV) has lead to virtual eradication of poliomyelitis. However, wild poliovirus is still endemic in some less developed countries, and there is still a risk of importation of wild-virus poliomyelitis as result of immigration from these areas. Therefore, a serologic study of the immunologic status to poliovirus was carried out in 242 immigrants from less developed countries in the Veneto Region (NorthEast Italy). The overall prevalence of serum neutralizing antibodies was 98.3 percent for poliovirus type 1, 99.6 percent for type 2, and 95.9 percent for type 3. The modal titres were 1:128 (21.1 percent), 1:512 (26.4 percent), and 1:32 (22.3 percent) for poliovirus type 1, type 2, and type 3, respectively. No subject was simultaneously lacking neutralizing antibodies to all three polioviruses