Immunogenicity Study onBivalent Inactivated Vaccines of H5N1 and H7N9
Subtype Influenza in Quailsand Pigeons
In order to evaluate the safety and immuneeffects of the bivalent inactivated vaccine(H5N1 Re-8 + H7N9 H7-Re1 strain)of recombinant influenza virus(H5+H7)in quails and pigeons,the bivalent inactivated vaccines produced by HarbinWeike Biotechnology Development Company were immunized in quails and youngpigeons from December 2017 to June 2018. The dose for a quail/pigeon was 0.3/1mL in first immunization at 25 days of age and enhanced immunization at 46 daysof age respectively. The clinical manifestations of poultry flocks wereobserved and the titers of antibodies were determined by collecting serumsregularly. The results showed that the titers of anti-HI antibodies of H5 and H7subtypes reached peak values 21 days after first immunization in quails with(7.7±1.3)log2 and(8.5±1.3)log2 respectively. The duration of antibody eligibility exceeding 70%was about 35 days. The titers of anti-HI antibodies of H5 and H7 subtypesreached peak values 7 days after enhanced immunization with(9.7±0.9)log2 and(10.3±0.9)log2,respectively. The effect duration ofantibodies against H5 and H7 subtypes exceeding 70% were about 147 and 175 daysrespectively. The titers of H5 and H7 antibodies reached their peaks 21 daysafter first immunization in young pigeons with(9.8±0.8)log2 and(10.4±1.1)log2 respectively. The period when thequalification rates of the two subtypes of antibodies exceeded 70% was morethan 181 days. The titers of H5 and H7 antibodies reached their peaks 7 daysafter enhanced immunization with(10.2±1.0)log2 and(10.7±0.9)log2,respectively. After 189 days,the titers were(5.4±1.3)log2 and(6.1±1.5)log2 respectively,and the qualification rates were 96.7% and 100% respectively. Noserious side effects were found in clinical observation. The results showedthat(H5+H7)bivalent inactivated vaccine was safe and effectivefor quails and pigeons. Therefore,it was recommended that quails should be immunized at25 days of age,and they should receive enhanced immunes at46 days and 180 days at the dose of 0.3 mL. The pigeons should receive fistinoculation at 25 days of age,and enhanced immunizations every 6 months with the dose of 1 mL.