Impact of Mixed Equine Influenza Vaccination on Correlate of Protection in Horses

Abstract

To evaluate the humoral immune response to mixed Equine Influenza vaccination, a common practice in the field, an experimental study was carried out on 42 unvaccinated thoroughbred weanling foals divided into six groups of seven. Three groups were vaccinated using a non-mixed protocol (Equilis® Prequenza-Te, Proteqflu-Te® or Calvenza-03®) and three other groups were vaccinated using a mix of the three vaccines mentioned previously. Each weanling underwent a primary EI vaccination schedule composed of two primary immunisations (V1 and V2) four weeks apart followed by a third boost immunisation (V3) six months later. Antibody responses were monitored until one-year post-V3 by single radial haemolysis (SRH). The results showed similar antibody responses for all groups using mixed EI vaccination and the group exclusively vaccinated with Equilis® Prequenza-TE, which were significantly higher than the other two groups vaccinated with Proteqflu-TE® and Calvenza-03®. All weanlings (100%) failed to seroconvert after V1 and 21% (9/42) still had low or no SRH antibody titres two weeks post-V2. All weanlings had seroconverted and exceeded the clinical protection threshold one month after V3. The poor response to vaccination was primarily observed in groups exclusively vaccinated with Proteqflu-Te® and Calvenza-03®. A large window of susceptibility (3–4.5-month duration) usually called immunity gap was observed after V2 and prior to V3 for all groups. The SRH antibody level was maintained above the clinical protection threshold for three months post-V3 for the groups exclusively vaccinated with Proteqflu-Te® and Calvenza-03®, and six months to one year for groups using mixed EI vaccination or exclusively vaccinated with Equilis® Prequenza-Te. This study demonstrates for the first time that the mix of EI vaccines during the primary vaccination schedule has no detrimental impact on the correlate of protection against EIV infection.

A novel vaccine adjuvant based on straight polyacrylate potentiates vaccine-induced humoral and cellular immunity in cynomolgus macaques

“…27 Another study using PCPP for the intranasal delivery into mice of a formalin-inactivated bovine RSV (FI-bRSV) vaccine combined with immunostimulatory CpG oligodeoxynucleotides indicated that the FI-bRSV /CpG/PCPP co-formulation could induce virus neutralizing antibody responses in the serum, IFN-γ responses in the spleen and mucosal IgA responses in the lung, as well as protection from bRSV challenge. 28,29,30 These studies highlight the potential of such polyanionic adjuvants, which are also advantageous in terms of readiness of supply, easiness of formulation by simple mixing processes and quality control by using nuclear magnetic resonance (NMR) and high-performance size exclusion chromatography (HPSEC) techniques. 8 The aim of the present study was to confirm the adjuvant effect of SPA09 in a higher animal species closest to human, i.e.…”

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

“…While the vaccination schedule is similar between commercially available EIV vaccines, there were no recommendations for use of different EIV vaccines in the horse immunization schedule. However, the use of different commercial vaccines at different time points is a very common practice in the equine industry; this method is called the mixed regime [ 36 ]. Previous studies have already shown that the Calvenza-03 EIV/EHV ® vaccine induces the protective antibody titer immediately after immunization [ 29 , 36 ].…”

“…However, the use of different commercial vaccines at different time points is a very common practice in the equine industry; this method is called the mixed regime [ 36 ]. Previous studies have already shown that the Calvenza-03 EIV/EHV ® vaccine induces the protective antibody titer immediately after immunization [ 29 , 36 ]. No clear data is available regarding the long-term persistence of EIV-specific humoral antibody response.…”

The sixth revolution in pediatric vaccinology: immunoengineering and delivery systems

“… 53 However, the role of individual components in generating these immune responses is unknown. At present, ISCOM technology has been approved only for veterinary vaccines; 54 however human clinical trials are currently ongoing for the development of melanoma vaccines. 55 …”