Vaccine efficacy in HPAI: A meta-analysis
A systematic review and meta-analysis re-evaluate the efficacy of vaccines against highly pathogenic avian influenza (HPAI) virus in poultry. This study sheds light on the importance of vaccination in controlling HPAI outbreaks among poultry. The global spread of the HPAI A(H5N1) clade 2.3.4.4b virus since 2021 has had a significant impact on the need for re-evaluation of vaccination strategies. The spread of the HPAI virus has led to significant morbidity and mortality among domestic poultry, affecting the supply chain of poultry products and human food safety. Conventional control measures such as biosecurity and mass culling have been recognized as challenging and unsustainable in effectively controlling the spread of the virus. Overall, the ongoing global spread of the HPAI A(H5N1) clade 2.3.4.4b virus underscores the importance of re-evaluating and potentially enhancing vaccination strategies to effectively combat the spread of HPAI in poultry. The meta-analysis on avian influenza vaccine efficacy in poultry provides updated and unbiased assessments, showing efficacy ranging from 78% to 97% depending on vaccine platforms and strain matches. Live recombinant vaccines exhibited the highest efficacy at 97%, while inactivated recombinant vaccines had an overall efficacy of 90%. Commercial vaccines showed an overall efficacy of 91%, with 96% efficacy against homologous strains and 90% efficacy against heterologous strains. Vaccination, while not completely preventing HPAI-related mortality, is crucial in a global avian influenza control strategy to reduce economic losses and enhance food security. Concerns about silent transmission and mutation risks are addressed, indicating that vaccination is unlikely to mask HPAI outbreaks.
