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Journal of Clinical Immunology and Allergy
ISSN: 2471-304X
E u r o p e a n C o n g r e s s o n
Vaccines & Vaccination
and Gynecologic Oncology
Vaccines & Vaccination and Gynecologic Oncology 2018
O c t o b e r 2 6 - 2 7 , 2 0 1 8
B u d a p e s t , H u n g a r y
Biography
Mohamed Dilai is a Veterinarian graduated fromHassan II Insti-
tute for Agronomy and Veterinary Medicine in Morocco in 2008.
He started his career in the pharmaceutical industry at Elanco
Animal health and stayed for a period of 3 years. In 2012, he
joined the National Horse Institute in Rabat and started his PhD
in 2014 for the study of equine influenza. In 2016, he joined the
Hassan II Institute for Agronomy and Veterinary Medicine as a
Clinician in Equine Department.
dilaimohamed.iav@gmail.comImpact of mixed equine influenza vaccination on correlate of
protection in horses
Mohamed Dilai
1
, Mohammed Piro
1
, Mehdi El Harrak
2
, Stéphanie
Fougerolle
3,4
, Mohammed Dehhaoui
1
, Asmaa Dikrallah
1
, Loïc
Legrand
3,4
, Romain Paillot
3,4
and Ouafaa Fassi Fihri
1
1Hassan II Institute for Agronomy and Veterinary Medicine-Rabat, Morocco
2
MCI Animal Health, Morocco
3
Universite de UniCaen Normandie-BIOTARGEN, France
4
LABÉO Frank Duncombe, France
Mohamed Dilai et al., Journal of Clinical Immunology and Allergy, Volume: 4
DOI: 10.21767/2471-304X-C2-005
I
n order 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 weanlings foals divided into 6 groups of 7.
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 foal underwent a primary
EI vaccination schedule composed of two primary immunisations (V1 and V2) 4
weeks apart followed by a third boost immunisation (V3) 6 months later. Antibody
responsesweremonitored until one-year post-V3 by single radial hemolysis (SRH),
a correlate of protection against equine influenza virus (EIV) infection. 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 2 groups vaccinated with Proteqflu-TE® and
Calvenza-03®. All the weanlings (100%) failed to seroconvert after V1 and 21%
(9/42) still had low or no SRH antibody titres 2 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
vaccinatedwith Proteqflu-Te®and Calvenza-03®. A largewindowof susceptibility
(3 to 4.5 months duration) usually called immunity gap was observed after V2 and
prior to V3 for all groups. The SRH antibody level wasmaintained above the clinical
protection threshold for 3 months post-V3 for the groups exclusively vaccinated
with Proteqflu-Te® and Calvenza-03®, 6 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 themix of EI vaccines during the primary
vaccination schedule has no detrimental impact on the correlate of protection
against EIV infection.
Euro Vaccines 2018