Abstract Title
Duration of immunity of a self-amplifying RNA H5 vaccine against highly pathogenic avian influenza H5Nx 2.3.4.4b clade in mule ducks
Abstract
Highly pathogenic avian influenza (HPAI) H5Nx virus, clade 2.3.4.4b, can induce disease in commercial ducks. Since it became a critical issue, France decided to vaccinate all its commercial ducks against HPAI. The self-amplifying RNA technology opens new avenues in terms of efficient vaccination against a moving target, safety, and differentiating infected from vaccinated animals (DIVA) strategy.
This study aimed at assessing the duration of immunity of a self-amplifying RNA H5 vaccine in mule ducks after challenge using a recent European HPAI virus strain of 2.3.4.4b clade.
Thirty-nine commercial ducklings were vaccinated during their first week of life and boosted three to four weeks later. Nineteen of them were challenged at six weeks of age, whereas the remaining twenty were challenged at thirteen weeks of age. Ten controls were also challenged each time.
Post-challenge clinical monitoring lasted for two weeks. Oro-pharyngeal as well as cloacal swabs were collected on days 1, 2, 4, 7, 10 and 14 post-challenge for virus detection and quantification. Blood samples were collected and tested by H5 and NP indirect ELISA tests.
Controls showed strong signs of infection whereas all vaccinated ducks did not; a significant shedding reduction was recorded in vaccinates versus controls. Most of the vaccinated ducks were seronegative by H5 ELISA test at the time of the second challenge. Altogether, these data support a duration of immunity of nine weeks post-booster vaccination in mule ducks, even in the absence of a persistently detectable antibody response.
This study aimed at assessing the duration of immunity of a self-amplifying RNA H5 vaccine in mule ducks after challenge using a recent European HPAI virus strain of 2.3.4.4b clade.
Thirty-nine commercial ducklings were vaccinated during their first week of life and boosted three to four weeks later. Nineteen of them were challenged at six weeks of age, whereas the remaining twenty were challenged at thirteen weeks of age. Ten controls were also challenged each time.
Post-challenge clinical monitoring lasted for two weeks. Oro-pharyngeal as well as cloacal swabs were collected on days 1, 2, 4, 7, 10 and 14 post-challenge for virus detection and quantification. Blood samples were collected and tested by H5 and NP indirect ELISA tests.
Controls showed strong signs of infection whereas all vaccinated ducks did not; a significant shedding reduction was recorded in vaccinates versus controls. Most of the vaccinated ducks were seronegative by H5 ELISA test at the time of the second challenge. Altogether, these data support a duration of immunity of nine weeks post-booster vaccination in mule ducks, even in the absence of a persistently detectable antibody response.
Co-Author(s)
C. Cazaban1, A.L. Vecsei2, Z. Gyuro2, E. Rausch2, K. Kamrud1, S. Comte1
1: Ceva Animal Health, Libourne, France; 2: Ceva Animal Health, Budapest, Hungary.
Abstract Category
Diagnostics, vaccination, or other mitigation strategies for poultry and wildlife