Equine influenza virus and vaccines

Fatai S. Oladunni, Saheed Oluwasina Oseni, Luis Martinez-Sobrido, Thomas M. Chambers

Research output: Contribution to journalReview articlepeer-review

25 Scopus citations


Equine influenza virus (EIV) is a constantly evolving viral pathogen that is responsible for yearly outbreaks of respiratory disease in horses termed equine influenza (EI). There is currently no evidence of circulation of the original H7N7 strain of EIV worldwide; however, the EIV H3N8 strain, which was first isolated in the early 1960s, remains a major threat to most of the world’s horse populations. It can also infect dogs. The ability of EIV to constantly accumulate mutations in its antibody-binding sites enables it to evade host protective immunity, making it a successful viral pathogen. Clinical and virological protection against EIV is achieved by stimulation of strong cellular and humoral immunity in vaccinated horses. However, despite EI vaccine updates over the years, EIV remains relevant, because the protective effects of vaccines decay and permit subclinical infections that facilitate transmission into susceptible populations. In this review, we describe how the evolution of EIV drives repeated EI outbreaks even in horse populations with supposedly high vaccination coverage. Next, we discuss the approaches employed to develop efficacious EI vaccines for commercial use and the existing system for recommendations on updating vaccines based on available clinical and virological data to improve protective immunity in vaccinated horse populations. Understanding how EIV biology can be better harnessed to improve EI vaccines is central to controlling EI.

Original languageEnglish
Article number1657
Issue number8
StatePublished - Aug 2021

Bibliographical note

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • Adaptive immunity
  • Cellular immunity
  • Equine influenza
  • Equine influenza vaccine
  • Equine influenza virus
  • Experimental infection
  • H3N8
  • Humoral immunity
  • Surveillance

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology


Dive into the research topics of 'Equine influenza virus and vaccines'. Together they form a unique fingerprint.

Cite this