Immunogenicity of trivalent subunit versus virosome-formulated influenza vaccines in geriatric patients.
The safety and immunogenicity of a commercial trivalent subunit influenza vaccine and an experimental virosome-formulated influenza vaccine were evaluated among geriatric patients in a double-blind, randomized manner. The virosome vaccine was produced by incorporating hemagglutinin (HA) into the membrane of liposomes composed of phosphatidylcholine. Both vaccines elicited a significant (P < 0.01) rise in the geometric mean anti-HA antibody titer to all three vaccine components 1 month after immunization. However, significantly (P < 0.005) more subjects vaccinated with the virosome preparation mounted a more than fourfold rise to the A/Singapore and A/Beijing strains compared with those who received subunit vaccine. The percentage of patients who attained protective levels (anti-HA titer > or = 40) of anti-A/Beijing antibody was also significantly (P < 0.005) higher in the virosome group. Subjects who possessed non-protective baseline antibody levels to the A/Singapore and A/Beijing strains were more likely (P < 0.005-0.030) to achieve protective levels after immunization with the virosome vaccine than with the subunit vaccine. Of particular clinical significance was the fact that 68.4% of subjects immunized with the virosome vaccine attained protective levels of antibody to all three vaccine components versus 38% for the subunit vaccine (P = 0.010).
Conne
P
P
Hôpital de Loëx, Hôpitaux Universitaires de Genève, Switzerland.
Gauthey
L
L
Vernet
P
P
Althaus
B
B
Que
J U
JU
Finkel
B
B
Glück
R
R
Cryz
S J
SJ
D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood*; D004311:Double-Blind Method; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D007114:Immunization; D007252:Influenza Vaccines / Q000276:immunology*; D008297:Male; D008875:Middle Aged
D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines