title: Efficacy of a non-updated, Matrix-C-based equine influenza subunit-tetanus vaccine following Florida sublineage clade 2 challenge.
abstract: Assessing the ability of current equine influenza vaccines to provide cross-protection against emerging strains is important. Horses not vaccinated previously and seronegative for equine influenza based on haemagglutination inhibition (HI) assay were assigned at random to vaccinated (n=7) or non-vaccinated (control, n=5) groups. Vaccination was performed twice four weeks apart with a 1 ml influenza subunit (A/eq/Prague/1/56, A/eq/Newmarket/1/93, A/eq/Newmarket/2/93), tetanus toxoid vaccine with Matrix-C adjuvant (EquilisPrequenza Te). All the horses were challenged individually by aerosol with A/eq/Richmond/1/07 three weeks after the second vaccination. Rectal temperature, clinical signs, serology and virus excretion were monitored for 14 days after challenge. There was no pain at the injection site or increases in rectal temperature following vaccination. Increases in rectal temperature and characteristic clinical signs were recorded in the control horses. Clinical signs were minimal in vaccinated horses. Clinical (P=0.0345) and total clinical scores (P=0.0180) were significantly lower in the vaccinated than in the control horses. Vaccination had a significant effect on indicators of viraemia - the extent (P=0.0006) and duration (P=<0.0001) of virus excretion and the total amount of virus excreted (AUC, P=0.0006). Vaccination also had a significant effect (P=0.0017) on whether a horse was positive or negative for virus excretion during the study. Further research is needed to fully understand the specific properties of this vaccine that may contribute to its cross-protective capacity.
authors.affiliation: Global R&D, MSD Animal Health, Boxmeer, The Netherlands.
authors.forename: H G W
authors.initials: HG
authors.lastname: Pouwels
authors.affiliation: Global R&D, MSD Animal Health, Boxmeer, The Netherlands.
authors.forename: S M A
authors.initials: SM
authors.lastname: Van de Zande
authors.affiliation: Global Companion Animal Business, MSD Animal Health, Intervet International bv, PO Box 31, Boxmeer 5830 AA, The Netherlands.
authors.forename: L J I
authors.initials: LJ
authors.lastname: Horspool
authors.affiliation: Global Clinical Research, MSD Animal Health, Boxmeer, The Netherlands.
authors.forename: M J H
authors.initials: MJ
authors.lastname: Hoeijmakers
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D006734:Horse Diseases / Q000276:immunology* / Q000517:prevention & control*; D006736:Horses; D007115:Immunization Schedule; D053123:Influenza A Virus, H3N8 Subtype / Q000276:immunology; D053126:Influenza A Virus, H7N7 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D013745:Tetanus Toxoid / Q000276:immunology; D013997:Time Factors; D014611:Vaccination / Q000662:veterinary*; D017778:Vaccines, Combined / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D013745:Tetanus Toxoid; D017778:Vaccines, Combined