Open, randomized study to compare the immunogenicity and reactogenicity of an influenza split vaccine with an MF59-adjuvanted subunit vaccine and a virosome-based subunit vaccine in elderly.

BACKGROUND

An open, randomized, multicenter study was carried out in elderly to compare the immunogenicity and reactogenicity of a conventional influenza split vaccine (SpV) with an MF59-adjuvanted subunit vaccine (aSuV) and a virosome-based subunit vaccine (vSuV) since earlier studies reported better immunogenicity for adjuvanted and virosome-based vaccines.

PATIENTS AND METHODS

A total of 840 subjects, aged 60 years or more, who had not been vaccinated or diagnosed with influenza in the preceding season were investigated. Hemagglutination-inhibition antibody titers were measured, and signs and symptoms recorded.

RESULTS

The three vaccines exceeded EU efficacy requirements for subjects aged older than 60 years and seroprotective levels (titers > 1:40) were equally maintained with the three vaccines during 8 months post vaccination. SpV was as immunogenic as aSuV for the A/H3N2 strain (p < 0.0001) and significantly more immunogenic than aSuV for A/H1N1 strain (p = 0.0006). SpV was as immunogenic as vSuV for all three strains and significantly more immunogenic than vSuV for the A/H1N1 strain (p < 0.0001). In terms of reactogenicity, aSuV showed a higher rate of solicited local signs and symptoms than SpV (p = 0.021) and vSuV (p = 0.046), respectively. Incidence of solicited general symptoms was comparable on all treatments. No serious adverse event related to vaccination was reported.

CONCLUSION

These findings suggest that all three vaccines are highly immunogenic with an acceptable reactogenicity profile and that they are appropriate for use in elderly.