Response of Sport Horses to Different Formulations of Equine Influenza Vaccine

Abstract

The international governing body of equestrian sports requires that horses be vaccinated against equine influenza within 6 months and 21 days of competing. The aim of this study was to compare the antibody response of young sport horses to six-monthly booster vaccination with equine influenza vaccines of different formulations. An inactivated vaccine was allocated to 35 horses and subunit and recombinant vaccines were allocated to 34 horses each. After vaccination, all horses were monitored for evidence of adverse reactions. Whole blood samples were collected at the time of vaccination and on nine occasions up to six months and 21 days post vaccination. Antibodies against equine influenza were measured by single radial haemolysis. Transient fever and injection site reactions were observed in several horses vaccinated with each vaccine. Only two horses failed to seroconvert post booster vaccination but there was a delayed response to the recombinant vaccine. The antibody response to the recombinant vaccine was lower than that induced by the whole-inactivated and subunit vaccines up to three months post vaccination. Thereafter, there was no significant difference. By six months post vaccination, the majority of horses in all three groups were clinically but not virologically protected. There was minimal decline in antibody titres within the 21-day grace period.

Equine Influenza Virus and Vaccines

“…This has necessitated recent vaccine strategies to aim at the possibility of inducing robust EIV-specific antibody- and T-cell-driven long-term immune responses. Several studies have investigated the efficacy and safety profiles, duration of immunity, immunity gap, and the level of protective immunity evoked by ISCOM/ISCOMATRIX TM vaccine in horses following experimental challenge infection with a wild-type (WT) EIV [ 104 , 105 , 108 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 ]. While most of these studies investigated T H 2 antibody-based response, studies focused on T H 1-mediated immune protection following vaccination with EIV-ISCOM/ISCOMATRIX TM in horses are limited.…”

A Saccharomyces cerevisiae Fermentation Product (Olimond BB) Alters the Early Response after Influenza Vaccination in Racehorses

“…None of the horses of either group displayed an enhanced (>38.5 °C) body temperature or swelling at the site of injection 24 h after vaccination. This may be due to the low number of vaccinated horses, since transient fever after vaccination against influenza was reported for several of 34 race horses when analysing the effects of 3 different influenza vaccines [ 27 ]. Concomitant with absent clinical side effects, serum amyloid A values remained largely unchanged after vaccination ( Table 2 ).…”

Immunogenicity of Calvenza-03 EIV/EHV® Vaccine in Horses: Comparative In Vivo Study

“…Most equine organizations require vaccination of horses, at different intervals, to enter competitions and shows [ 11 ]. There are several whole-inactivated virus-based vaccines [ 12 , 13 , 14 , 15 ], subunit vaccines, canarypox vectored vaccines [ 16 ] and modified live viral vaccines that are commercially available ( Table 1 ) [ 17 , 18 , 19 , 20 ]. Reverse genetic-based modified live-attenuated EI vaccines are currently under study [ 21 , 22 ].…”