Identification of Efficacious Vaccines against Contemporary North American H7 Avian Influenza Viruses

Erica Spackman, Mary J. Pantin-Jackwood, Ioannis Sitaras, Christopher B. Stephens, David L. Suarez

Research output: Contribution to journalArticlepeer-review


Five vaccines, including four inactivated, whole-virus water-in-oil adjuvanted vaccines and a commercial nonreplicating alphavirus-vectored RNA particle (RP) vaccine were evaluated in chickens for their ability to provide protection against challenge with a recent H7 highly pathogenic avian influenza virus (AIV) from the United States (A/turkey/IN/1403-1/2016 H7N8). One of the inactivated vaccines and the RP vaccine were prepared with A/turkey/IN/16-01571-6/2016 H7N8 low pathogenic AIV (LPAIV; TK/IN/16), which is identical to the challenge virus, except for the proteolytic cleavage site of the hemagglutinin protein. The remaining three inactivated vaccines were prepared with other North American H7 LPAIVs. The hemagglutination inhibition assay was used to evaluate the antigenic relationships among the vaccines and selected recent H7 AIV isolates. All five vaccines provided protection against mortality. The inactivated vaccines reduced virus shedding significantly at 2 and 4 days post challenge compared with sham-vaccinated chickens. In contrast, the RP vaccine did not significantly reduce virus shedding. The inactivated vaccine prepared with TK/IN/16 elicited the highest antibody responses, which suggests it is a strong candidate for use as an antigen for North American H7 AIVs. Antigenic distance calculations showed that the four inactivated vaccine strains and other recent North American H7 isolates are antigenically similar, which suggests that the vaccines evaluated here would be similar enough to provide protection to other North American H7 AIVs. If future H7 outbreaks in poultry warrant vaccination, the field strain can be rapidly evaluated with these antigens and, if adequately related, one of these characterized strains may be used.

Original languageEnglish (US)
Pages (from-to)113-121
Number of pages9
JournalAvian diseases
Issue number1
StatePublished - Mar 2021
Externally publishedYes


  • alphavirus vectored vaccine
  • antigenic cartography
  • avian influenza
  • H7 influenza
  • highly pathogenic avian influenza
  • poultry vaccination
  • RNA particle vaccine

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • General Immunology and Microbiology


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