Immunogenicity, safety and tolerability of varying doses and regimens of inactivated hepatitis A virus vaccine in Navajo children.
The Navajo are known to be at high risk for hepatitis A virus (HAV) infection. This study investigated the safety and immunogenicity of an investigational, alum-adjuvanted, formalin-inactivated HAV vaccine (VAQTA) developed by Merck Research Laboratories in Navajo children. One hundred two of 212 children, ages 4 to 12 years, were HAV-seronegative (< 10 mIU/ml by an enhanced sensitivity modification of the HAVAB; Abbott). Ninety of these children received the HAV vaccine. Study participants were given vaccines containing various viral protein concentrations: Group A (n = 18), 6 units; Group B (n = 36), 13 units; and Group C (n = 36), 25 units HAV protein (1 unit approximately 1 ng viral protein antigen). Three-dose (0, 8, 24 weeks) and two-dose (0, 24 weeks) regimens were compared in subgroups within B and C. The vaccine was well-tolerated and there were no serious adverse reactions; no vaccinee developed hepatitis A. After 1 dose 82 to 100% of children seroconverted (> or = 10 mIU/ml, modified HAVAB; Abbott) and 100% seroconverted after 2 doses. After 1 dose the geometric mean titer for antibody was: Group A, 22 mIU/ml; Group B, 18 mIU/ml; and Group C, 38 mIU/ml. After 3 doses geometric mean titers increased to 10,106 mIU/ml in Group A, 7258 mIU/ml in Group B and 11,856 mIU/ml in Group C. Further field studies are indicated to evaluate its use in high risk populations, such as the Navajo.
Newcomer
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Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21205.
Rivin
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B
Reid
R
R
Moulton
L H
LH
Wolff
M
M
Croll
J
J
Johnson
C
C
Brown
L
L
Nalin
D
D
Santosham
M
M
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006506:Hepatitis A / Q000208:ethnology / Q000276:immunology / Q000517:prevention & control*; D022362:Hepatitis A Vaccines; D017957:Hepatitis A Virus, Human / Q000276:immunology*; D006508:Hepatitis Antibodies / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D007115:Immunization Schedule; D007125:Immunogenetics; D007198:Indians, North American; D008297:Male; D012044:Regression Analysis; D016036:Seroepidemiologic Studies; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*
D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D015164:Vaccines, Inactivated; D014761:Viral Hepatitis Vaccines