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John Beigel,
Katrin S Kohl,
Najwa Khuri-Bulos,
Lulu Bravo,
Patricia Nell,
S Michael Marcy,
Karen Warschaw,
Anna Ong-Lim, Gabriele Poerschke,
William Weston,
Jill A Lindstrom,
Gillian Stoltman,
Toby Maurer
Vaccine 08/2007; 25(31):5697-706. · 3.77 Impact Factor
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ABSTRACT: In Jiangsu, 30% of children between the ages of 5 and 8 years test seropositive for hepatitis A. The safety, tolerability, and immunogenicity of a 2-dose regimen (0, 6 months) of VAQTA (0.5 ml of 25U) administered IM in 50 healthy children aged 5 to 8 years without prior serological screening was evaluated. Blood samples were collected prior to the first dose and after each additional dose of VAQTA to determine the initial anti-HAV serostatus and response rates to the vaccine. Twelve children (24%) were initially seropositive and 38 (76%) were initially seronegative. Four weeks after the primary dose of VAQTA, 34 of the 38 subjects (89.5%, 95% CI 75 to 97) were anti-HAV seropositive. The geometric mean titer was 33.1 mIU/ml (95% CI 22.4 to 49.0). After the booster dose at 6 months, all the subjects were seropositive (37/37), giving a seroconversion of 100% (95% CI: 90, 100). The geometric mean titer was 7585.8 mIU/ml (95% CI: 5623.4 to 10,471.3). Adverse experiences were generally mild and transient. Results of this study are consistent with results from a previous double-blind randomized trial of this vaccine and confirm that VAQTA is highly immunogenic, and generally well-tolerated.
The Southeast Asian journal of tropical medicine and public health 01/2005; 35(4):949-53. · 0.60 Impact Factor
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ABSTRACT: The primary objective of this study was to estimate the efficacy of a recombinant hepatitis B vaccine (H-B-VAXII) in preventing chronic hepatitis B infection when given alone without concomitant hepatitis B immune globulin (HBIG) to healthy Thai infants born of HBeAg-positive carrier mothers. The infants received a 0.5 ml (5 micro g HBsAg) intramuscular injection of H-B-VAXII either at birth, 1, and 6 months of age (Schedule A) or at birth, 1, 2, and 12 months of age (Schedule B). Blood drawings for the determination of hepatitis B virus (HBV) serologic markers were scheduled 4, 9, and 13 months following the initial dose of vaccine. At 13 months, 5 (10%) of 50 infants vaccinated on Schedule A and 7 (14.9%) of 47 infants vaccinated on Schedule B had experienced chronic HBV infection. Based on an expected infection rate in unimmunized infants of either 70 or 90%, the overall efficacy for both schedules combined was estimated to be 82.3% (95% CI: 70.6, 90.6) or 86.2% (95% CI: 77.1, 92.7), respectively. Corresponding schedule-specific estimates were for Schedule A: 85.7% (95% CI: 68.8, 95.3) or 88.9% (95% CI: 75.8, 96.3) and for Schedule B: 78.7% (95% CI: 59.6, 91.1) or 83.4% (95% CI: 68.6, 93.1). These results suggest that in areas of high endemicity, where mothers may not always be screened for HBV infection, routine vaccination of infants at birth with a course of hepatitis B vaccine alone should be highly protective, even for very high-risk infants of HBeAg-positive mothers.
Vaccine 12/2002; 20(31-32):3739-43. · 3.77 Impact Factor
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ABSTRACT: A study involving more than 2,000 infants was conducted in Vietnam to assess the field effectiveness and immunogenicity of recombinant hepatitis B vaccine given at birth, 1 month, 2 months, without concomitant hepatitis B immune globulin (HBIG). All received a 5 microg dose of H-B-VAX II at birth. Infants born to non-carrier mothers (Group 1; N = 1798) then received 2.5 microg doses at 1 and 2 months of age, while infants of HBeAg-negative (Group 2; N = 125) or HBeAg-positive (Group 3; N = 88) carrier mothers received 5 microg doses. No Group 1 or 2 vaccinees were infected. In Group 3, 12 (14.6%) of 82 infants did become infected (estimated efficacy 84%). 98.0-98.6% of uninfected infants who were tested for anti-HBs developed a seroprotective concentration > or = 10 IU/L. In hyperendemic Vietnam, where routine maternal screening and passive-active prophylaxis of high-risk infants with vaccine plus HBIG is not feasible, administration of vaccine alone to all newborns may control effectively HBV infection.
Journal of Medical Virology 07/2002; 67(3):327-33. · 2.82 Impact Factor
