Possible correlation between low antigenic drift of A(H1N1) influenza viruses and induction of HI antibodies

Abstract

This study examined whether, during a seven-year period of low A(H1N1) influenza virus antigenic drift (1988-1989 and 1994-1995, winters), humoral antibody response of elderly volunteers to influenza vaccines could suggest a lack of antibody pressure for drift. In all the years studied A/Taiwan/1/86, the A(H1N1) vaccine component, had a low ability to induce protective hemagglutination-inhibiting (HI) antibody titres (> or = 1:40). However a similar low immunogenicity was found for some of the different A(H3N2) strain variants of influenza virus, co-circulating in the same period and showing a regular extent of antigenic variations. Although our data could be at least in part explained by the type of study population (elderly and repeatedly vaccinated), postepidemic serological studies did not evidence a consistently lower ability in mounting protective immune response in elderly people as compared with younger against the influenza strains studied. Therefore, our present results did not exclude a true low immunogenicity of A/Taiwan and of some A(H3N2) influenza strains, circulating in the winters examined. This suggests that, besides the necessity to evade prior immunity, additional factors could influence the frequency of influenza viruses antigenic drifts.

Quantitative review of antibody response to inactivated seasonal influenza vaccines

“…We identified 60 eligible articles published between 1987 and 2006 describing inactivated seasonal influenza vaccine immunogenicity studies conducted in the United States, Canada, Europe, Israel, and Russia 10 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 . We included 129 independent study arms of which 119 reported data on response to A/H1N1, 109 on influenza B, and 108 on A/H3N2 vaccine strains (Table 1).…”

“…We identified 60 eligible articles published between 1987 and 2006 describing inactivated seasonal influenza vaccine immunogenicity studies conducted in the United States, Canada, Europe, Israel, and Russia 10,22–80 . We included 129 independent study arms of which 119 reported data on response to A/H1N1, 109 on influenza B, and 108 on A/H3N2 vaccine strains (Table 1).…”