Efficacy of using concurrent vaccination protocols: Influenza and Herpesvirus

This study found that foals vaccinated concurrently with flu and rhino (herpesvirus) were as well protected and had no more side effects than those vaccinated separately two weeks apart.
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Primary vaccination in foals: a comparison of the serological response to equine influenza and equine herpesvirus vaccines administered concurrently or 2 weeks apart
Arch Virol. 2021 Jan 7. doi: 10.1007/s00705-020-04846-6. Online ahead of print.
Authors
Alexandra Allkofer 1 , Marie Garvey 2 , Evelyn Ryan 2 , Rachel Lyons 2 , Megan Ryan 2 , Gabija Lukaseviciute 2 , Cathal Walsh 3 , Monica Venner 4 , Ann Cullinane 5
Affiliations

1 Clinic for Horses, University of Veterinary Medicine Hanover, Hanover, Germany.
2 Virology Unit, The Irish Equine Centre, Johnstown, Naas, Co. Kildare, W91 RH93, Ireland.
3 Department of Mathematics and Statistics, University of Limerick, Limerick, Ireland.
4 Equine Clinic Destedt, Trift 4, 38162, Destedt, Germany. MVenner@gmx.de.
5 Virology Unit, The Irish Equine Centre, Johnstown, Naas, Co. Kildare, W91 RH93, Ireland. ACullinane@irishequinecentre.ie.

Abstract

This study compared concurrent and separate primary vaccination against equid alphaherpesviruses 1 and 4, genus Varicellovirus, subfamily Alphaherpesvirinae, family Herpesviridae, and equine influenza A virus, genus Alphainfluenzavirus, family Orthomyxoviridae. Their vernacular names are equine herpesvirus 1 and 4 (EHV1/4) and equine influenza virus (EIV). Infection with these respiratory pathogens is associated with loss of performance, interruption of training schedules, and on occasion, cancellation of equestrian events. Vaccination is highly recommended, and for some activities it is a mandatory requirement of the relevant authority. As there is a dearth of information relating to the impact of concurrent vaccination on the antibody response to EHV and EIV vaccines, they are usually administered separately, often 2 weeks apart. In a previous study of booster vaccination in Thoroughbred racehorses, concurrent vaccination with whole-virus inactivated carbopol-adjuvanted EHV and EIV vaccines did not impact negatively on the antibody response. In this study, investigations were extended to concurrent versus separate primary vaccination of warmblood foals. A field study was conducted to compare the immune response to a carbopol-adjuvanted EHV vaccine and an immune stimulating complex (ISCOM)-adjuvanted EI vaccine administered concurrently and 2 weeks apart. No adverse clinical reactions were observed, the pattern of EI and EHV antibody response was similar for both groups, and there was no evidence that concurrent primary vaccination compromised the humoral response. The results are of relevance to horse owners who wish to decrease veterinary costs, limit handling of young animals, and simplify record keeping by vaccinating concurrently.