Primary Outcome Measures:
- Percentage of subjects presenting an increase > 4 fold of antiH1N1 or antiH3N2 or anti-B haemagglutination inhibition antibody titer, 3 weeks following influenza vaccination. [ Time Frame: 21 days ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- geometric mean of haemagglutination antibody titer obtained at day 21 with or without IFNa [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- influenza virus strain-specific IgG total, IgG2a, IgG2a/IgG1 ratio, secretory IgA responses at day 21 in each group . [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- influenza virus strain-specific secretory IgA anti-influenza antibody titers in saliva 14 and 21 days following vaccination. [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- evaluation of individual response to IFNa treatment [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- levels of serologic alpha interferon and of anti- alpha -interferon at day 21. [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- Percentage of patients maintaining protective antibody titers 3 and 6 months following vaccination. [ Time Frame: 3 months and 6 months after ] [ Designated as safety issue: No ]
- Predictive factors of vaccine response (age, total lymphocyte cell count, CD4 cell count…) [ Time Frame: 21 days ] [ Designated as safety issue: No ]
- Evaluation of cellular vaccine response in a subgroup of subjects. [ Time Frame: 21 days ] [ Designated as safety issue: No ]
The protection afforded by the commonly used influenza sub-unit vaccines is thought to be due principally to the production of antibodies to viral haemagglutinin. The haemagglutination inhibitory (HAI) antibody titer is generally used as a surrogate marker of protection and a HAI antibody titer of 1:40 or greater is considered to confer protection. This is attained, however, in only 50% of elderly subject. Thus, there is an unmet need for an effective non-toxic adjuvant capable of enhancing the antibody response to influenza and other vaccines. Type I IFNs have been shown to induce B-lymphocytes to differentiate into antibody producing plasma cells and to be necessary for the production of both specific and polyclonal IgGs in response to influenza infection. Furthermore, type I IFNs increase the primary antibody response to a soluble antigen in vivo, and increase the production of all IgG sub-classes. Type I IFNs play a key role in adjuvant-induced Th1 responses. Thus, we evaluated the safety of sublingual administration of IFNa and its effect on immune response to influenza vaccination.Institutionalized subjects, aged 75 or more, were randomly assigned to two groups to receive in a double-blind fashion either 107 IU of Intron ATM in 1 ml of isotonic saline or 1 ml of saline alone (placebo) administered sublingually. Interferon or placebo were retained in the mouth for at least 30 seconds prior to ejection. All subjects were then vaccinated, within 30 minutes, with a single intramuscular injection (im) of influenza vaccine (InfluvacTM, Solvay Pharma, France).
The primary objective of this study is to compare the immunogenicity percentage of subjects who increased up to 4 fold their HAI antibody titer at day 21) obtained in the IFN treated group relative to the placebo treated group.
The secondary objectives are to compare mean HAI antibodies titers obtained in the two groups at day 21 ; specific IgG, IgG2a, IgG2a/IgG1 ratio and secretory IgA titers in the 2 groups; specific secretory IgA titers in saliva; durability of protective HAI antibodies titers 3 and 6 months after the vaccination and the safety of sublingual administration of IFNa.
Purpose
