An evaluation of vaccination in poultry as an intervention strategy for control of H5N1 avian influenza infection

Abstract

Background H5N1 highly pathogenic avian influenza (HPAI) continues to be a serious threat to human and animal health with upwards of 840 human infections and 447 deaths since 2003. It also has pandemic potential. Vaccination in poultry has been employed in a number of countries as a strategy to control the virus. Methods A literature search was performed using PubMed and Google to locate relevant articles in English that examined the effectiveness of vaccination for controlling H5N1 HPAI. Results Experimental evidence demonstrates that vaccination is able to reduce infection rates, decrease replication and excretion of virus, reduce morbidity and mortality and prevent transmission in poultry. Its use in the field has met with mixed success. Clearly positive results in reduction of outbreaks in poultry and human infections have been seen in Vietnam and Hong Kong but not in some other endemic countries. The use of vaccination as a strategy is also challenged by such factors as the emergence of antigenic variants, non-sterilising immunity, and practical on the ground issues. Conclusion Despite some limitations vaccination of poultry as a part of a holistic H5N1 control strategy to protect human and animal health is recommended in a number of circumstances but a clear objective must be established. Further efforts are required in the development of vaccines and vaccination strategy but also in more clearly determining the additional benefit derived from vaccination over other control methods.