Research and development of high-dose inactivated quadrivalent influenza serial vaccines (split virion) proposed to be used for elderly adults / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To evaluate the immunogenicity of high-dose inactivated quadrivalent influenza serial vaccines (split virion) for elderly people.@*Methods@#Immunogenicity assays on mouse as research animal model with inactivated quadrivalent influenza serial vaccines (split virion) were carried out. Then rates of seroconversion and geometric mean hemagglutination inhibition titers (GMTs) at day 21 after the last vaccination among those who received high-dose (HD) A+ B influenza vaccine, were compared with those who received other vaccines by hemagglutination inhibition (HAI) test.@*Results@#The result of HAI test showed in HD serial vaccine groups, GMTs for all kinds of HA in the two HD serial vaccine groups were significantly different from that of the two SD serial vaccine groups, respectively (P<0.0001), but not the titers for A3 in one B dose first group. Further- more, GMTs for strain A in one B dose first groups were significantly higher than that of one B dose first groups in both HD and SD groups, and vice versa in the GMTs for strain B. The result of the assay of the impact of different immunization intervals of HD serial influenza vaccine on immunogenicity indicated that the immunity responses in 7 or 10 d groups were higher than that in 3 d group.@*Conclusions@#It is a new method to prevent the flu for elderly by HD A+ B serial influenza vaccine, whose HA dose per immunization was reduced into two injections, worked best when the immunization interval was 7-10 d. The protective immunity can be improved by selecting immune procedure of the serial vaccine according to the epidemic type surveillance of influenza virus A and B strains.