Protective efficacy of an H5/H7 trivalent inactivated vaccine(H5-Re13,H5-Re14, and H7-Re4 strains) in chickens, ducks, and geese against newly detected H5N1, H5N6, H5N8, and H7N9 viruses

Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains(H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin(HA) and neuraminidase(NA) genes of an H5 N6 virus that bears the clade 2.3.4.4 h HA gene, H5-Re14 contains the HA and NA genes of an H5 N8 virus that bears the clade 2.3.4.4 b HA gene, and H7-Re4 contains the HA and NA genes of H7 N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses(an H5 N1 virus, an H5 N6 virus, and an H5 N8 virus) bearing the clade 2.3.4.4 b HA gene, an H5 N6 virus bearing the clade 2.3.4.4 h HA gene, and an H7 N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4 h or 2.3.4.4 b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7 N9 viruses that are currently circulating in nature.

Protective efficacy of an H5/H7 trivalent inactivated vaccine produced from Re-11, Re-12, and H7-Re2 strains against challenge with different H5 and H7 viruses in chickens

We developed an H5/H7 trivalent inactivated vaccine by using Re-11, Re-12, and H7-Re2 vaccine seed viruses, which were generated by reverse genetics and derived their HA genes from A/duck/Guizhou/S4184/2017(H5N6) (DK/GZ/S4184/17) (a clade 2.3.4.4d virus), A/chicken/Liaoning/SD007/2017(H5N1) (CK/LN/SD007/17) (a clade 2.3.2.1d virus), and A/chicken/ Guangxi/SD098/2017(H7N9) (CK/GX/SD098/17), respectively. The protective efficacy of this novel vaccine and that of the recently used H5/H7 bivalent inactivated vaccine against different H5 and H7N9 viruses was evaluated in chickens. We found that the H5/H7 bivalent vaccine provided solid protection against the H7N9 virus CK/GX/SD098/17, but only 50–60% protection against different H5 viruses. In contrast, the novel H5/H7 trivalent vaccine provided complete protection against the H5 and H7 viruses tested. Our study underscores the importance of timely updating of vaccines for avian influenza control.

A Comparative Study on the Hemato-Biochemical and Immunological Effects of the Hexavalent FMD Vaccine Alone or in Combination with Trivalent FMD Vaccine in Cattle

Foot and mouth disease is the most contagious disease of mammals and has a great potential for causing severe economic loss in susceptible cloven-hoofed animals. Routine prophylactic vaccination in Egypt from 2012 till now has been conducted with Trivalent and/or hexavalent vaccine of MERIAL, against virus strains (O manisa + O-3039 + A Iran 05 + A Saudi 95 + Asia 1 + Sat2). This study aimed to evaluate the hemato-biochemical and immunological changes associated with the use of hexavalent vaccine alone or in combination with trivalent FMD vaccine. This study was carried out on 24 cattle divided into three groups eight cattle each. Group I served as control. Group II were selected from farms vaccinated with hexavalent FMD vaccine. Group III were selected from farms vaccinated with a combination of trivalent and hexavalent FMD vaccine. The results showed that both vaccinated groups showed a significant increase in total leukocytic count. Sera from hexavalent-trivalent vaccinated cattle demonstrated a significant increase in serum cortisol concentrations. Significant increase in serum activity of aspartate aminotransferase was recorded in animals vaccinated with a combination of hexavalent and trivalent vaccine. In addition, both regimes resulted in a significant increase in serum blood urea nitrogen compared to control. Both regimes induced a significant increase in serum levels of ceruloplasmin while phagocytic activity of neutrophils and phagocytic index was enhanced only by the hexavalent vaccine. Both vaccinated groups had significantly increased serum values of gamma globulins. These results suggested that hexavalent vaccine produced higher levels of safety and protective effects against FMD in cattle as compared to those produced by a combination of hexavalent and trivalent vaccines. It is also advisable to include the hexavalent vaccine within the program of obligatory and imperative vaccination against FMD.