Safety profile and immunogenicity of an inactivated vaccine derived from an attenuated strain of hepatitis A.
To determine the safety and immunogenicity of an inactivated hepatitis A vaccine, 56 healthy adult volunteers were randomly assigned to receive an intramuscular injection of 6.3, 12.5 or 25 ng of inactivated hepatitis A vaccine or placebo at 0, 2 or 4, and 24 weeks. Adverse reactions occurred with similar frequency in vaccine and placebo recipients and consisted primarily of pain or tenderness at the injection site. By 4 weeks after a single 6.3, 12.5 or 25 ng injection, seven, nine and ten out of ten vaccinees, respectively, had antibody detectable by a HAV AB assay modified to increase its sensitivity tenfold. All vaccinees had antibodies detectable by this assay within 2 weeks of their second inoculation. Geometric mean antibody levels increased with higher doses of vaccine (p = 0.05). Neutralizing antibody was detected within 4 weeks of a single inoculation in all vaccinees. Neutralizing antibody was detected after the third inoculation at dilutions of greater than or equal to 1:2048 in all 12.5 and 25 ng vaccinees. All 19 vaccinees tested at 24 months still had HAV antibodies detectable by a modified HAV AB assay. This inactivated hepatitis A vaccine appears to be well tolerated and immunogenic at doses of 6.3-25 ng. The choice of dose and vaccination schedule may depend on the rapidity with which seroconversion is desired.
Ellerbeck
E F
EF
Center for Immunization Research, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205.
Lewis
J A
JA
Nalin
D
D
Gershman
K
K
Miller
W J
WJ
Armstrong
M E
ME
Davide
J P
JP
Rhoad
A E
AE
McGuire
B
B
Calandra
G
G
D000293:Adolescent; D000328:Adult; D000956:Antigens, Viral / Q000302:isolation & purification; D004341:Drug Evaluation; D005260:Female; D005557:Formaldehyde; D006506:Hepatitis A / Q000276:immunology*; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000009:adverse effects* / Q000276:immunology*
D000956:Antigens, Viral; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D015164:Vaccines, Inactivated; D014761:Viral Hepatitis Vaccines; D005557:Formaldehyde