EFSA Journal (Oct 2023)

Vaccination of poultry against highly pathogenic avian influenza – part 1. Available vaccines and vaccination strategies

  • EFSA Panel on Animal Health and Animal Welfare (AHAW), European Union Reference Laboratory for Avian Influenza,
  • Søren Saxmose Nielsen,
  • Julio Alvarez,
  • Dominique Joseph Bicout,
  • Paolo Calistri,
  • Elisabetta Canali,
  • Julian Ashley Drewe,
  • Bruno Garin‐Bastuji,
  • Jose Luis Gonzales Rojas,
  • Christian Gortázar,
  • Mette Herskin,
  • Virginie Michel,
  • Miguel Ángel Miranda Chueca,
  • Barbara Padalino,
  • Helen Clare Roberts,
  • Hans Spoolder,
  • Karl Stahl,
  • Antonio Velarde,
  • Christoph Winckler,
  • Eleonora Bastino,
  • Alessio Bortolami,
  • Claire Guinat,
  • Timm Harder,
  • Arjan Stegeman,
  • Calogero Terregino,
  • Inmaculada Aznar Asensio,
  • Lina Mur,
  • Alessandro Broglia,
  • Francesca Baldinelli,
  • Arvo Viltrop

DOI
https://doi.org/10.2903/j.efsa.2023.8271
Journal volume & issue
Vol. 21, no. 10
pp. n/a – n/a

Abstract

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Abstract Several vaccines have been developed against highly pathogenic avian influenza (HPAI), mostly inactivated whole‐virus vaccines for chickens. In the EU, one vaccine is authorised in chickens but is not fully efficacious to stop transmission, highlighting the need for vaccines tailored to diverse poultry species and production types. Off‐label use of vaccines is possible, but effectiveness varies. Vaccines are usually injectable, a time‐consuming process. Mass‐application vaccines outside hatcheries remain rare. First vaccination varies from in‐ovo to 6 weeks of age. Data about immunity onset and duration in the target species are often unavailable, despite being key for effective planning. Minimising antigenic distance between vaccines and field strains is essential, requiring rapid updates of vaccines to match circulating strains. Generating harmonised vaccine efficacy data showing vaccine ability to reduce transmission is crucial and this ability should be also assessed in field trials. Planning vaccination requires selecting the most adequate vaccine type and vaccination scheme. Emergency protective vaccination is limited to vaccines that are not restricted by species, age or pre‐existing vector‐immunity, while preventive vaccination should prioritise achieving the highest protection, especially for the most susceptible species in high‐risk transmission areas. Model simulations in France, Italy and The Netherlands revealed that (i) duck and turkey farms are more infectious than chickens, (ii) depopulating infected farms only showed limitations in controlling disease spread, while 1‐km ring‐culling performed better than or similar to emergency preventive ring‐vaccination scenarios, although with the highest number of depopulated farms, (iii) preventive vaccination of the most susceptible species in high‐risk transmission areas was the best option to minimise the outbreaks' number and duration, (iv) during outbreaks in such areas, emergency protective vaccination in a 3‐km radius was more effective than 1‐ and 10‐km radius. Vaccine efficacy should be monitored and complement other surveillance and preventive efforts.

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