<p>Highly pathogenic H5Nx avian influenza viruses are endemic in animals in many countries. These viruses cause the severe diseases in chickens, but they cause much milder diseases in ducks. The vaccination is one of the tools to prevent the infections of ducks by highly pathogenic H5Nx avian influenza viruses. Here, we studied the efficacy of oil-adjuvanted H5 cleavage peptide vaccine in ducks. The vaccinated ducks challenged with H5N6 and H5N8 avian influenza viruses were protected without viral detection in the tracheal and cloacal swabs. The protective immunity in the immunized ducks lasted until 16&#xa0;weeks post-vaccination. Our results suggest that H5 cleavage site peptide vaccine can be one of the candidate vaccines to provide the protective immunity to ducks against H5Nx avian influenza viruses.<?oxy_aq_start??>Please confirm if the author names are presented accurately and in the correct sequence. Also, kindly confirm the details in the metadata are correct.<?oxy_aq_end??><?oxy_aqreply_start??>Yes, It's correct.<?oxy_aqreply_end??><?oxy_aq_start??>Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.<?oxy_aq_end??><?oxy_aqreply_start??>Yes, It's correct.<?oxy_aqreply_end??><?oxy_aq_start??>Please confirm the section headings are correctly identified.<?oxy_aq_end??><?oxy_aqreply_start??>Yes, It's correct.<?oxy_aqreply_end??><?oxy_aq_start??>Kindly check and confirm the edit made in the title.<?oxy_aq_end??><?oxy_aqreply_start??>Yes, It's OK.&#xa0;<?oxy_aqreply_end??><?oxy_aq_start??>LE: Kindly check and confirm whether the edit made in the article title is appropriate.<?oxy_aq_end??><?oxy_aqreply_start??>Yes, It's OK.&#xa0;<?oxy_aqreply_end??></p>