Compared with trivalent influenza vaccines, quadrivalent influenza vaccines are supposed to have greater protection against influenza B virus infections. In the manufacturing process, the researchers produced a novel quadrivalent subunit influenza vaccine that was distinct from the influenza vaccines. They tested the efficacy and immunogenicity of a quadrivalent subunit influenza vaccine in animal models.

To measure toxicity, 40 SD rats were randomly allocated to receive 1.0 ml of the studied vaccine or 0.9 percent sodium chloride solution intramuscularly. Eight rabbits were randomly allocated to receive 0.5 ml of tested vaccine or phosphate buffer solution intramuscularly to determine discomfort. For sensitization testing, 32 guinea pigs were randomly selected to be intramuscularly injected with high-dose tested vaccine, low-dose tested vaccine, ovalbumin, or 0.9% sodium chloride solution. 50 Mice were randomised in an immunogenicity evaluation with one vaccine, two doses of a test vaccine with a 14-day period, 0.5 ml of a trivalent subunit, 0.5 ml of a monovalent sub-unit or 0.5 ml of phosphate-buffer-insulate. There were no clear allergic signs found in the high-dose and the low-dose cohorts, and the sensitization assessment was negative in guinea pigs.

Geometric mean headers (GMTs) is comparable with those in tri vaccine and mono vaccine groups for common influenza strains in hemagglutination (HI) antibodies at day 28 in the quadri-vaccine one-dose groups and the quadri-vaccine two-dose groups. GMTs is slightly less in one-dose quadri-vaccines than the tri-vaccine or mono-vaccine classes in H1N1 antibodies and BV at day 42.