[Formation of humoral and secretory immunity in elderly persons with different schemes of immunization with flu vaccines]

The immunological efficacy of 5 protocols of immunization with two influenza vaccines are compared in 168 elderly subjects aged 64 to 87 years. Russian live cold-adapted reassortant trivalent (LCIV) and American inactivated cleaved trivalent (ICIV) influenza vaccines were used. The protocols of vaccination were as follows: 1) simultaneous vaccination with LCIV and ICIV and revaccination with LCIV after 1 months; 2) simultaneous vaccination with LCIV and ICIV and revaccination with placebo after 1 month; 3) vaccination and revaccination with LCIV; 4) vaccination with ICIV and revaccination with placebo; 5) vaccination and revaccination with placebo preparation (control); 6) vaccination with ICIV and revaccination with LCIV after 1 month. The incidence of significant increments and intensity of accumulation of serum (assessed by the hemagglutination inhibition test) and secretory (IgA) antibodies (assessed by enzyme immunoassay) was evaluated. For elderly subjects, simultancous vaccination with LCIV and ICIV followed by revaccination with LCIV is the most effective. After such vaccinations both secretory and humoral immune responses are characterized by the highest production of secretory IgA and serum antibodies. The quantitative parameters of both types of immune response in elderly subjects thus immunized are much higher than in young subjects vaccinated traditionally, that is, by LCIV or ICIV alone.