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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.com

Impact 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