Journal of Vaccine Research, 2025, Vol.15, No.1, 1-9 http://medscipublisher.com/index.php/jvr 5 the efficacy of these vaccines can be influenced by several factors, such as the situation of maternal antibodies in poultry, the matching degree between the vaccines and epidemic strains, and unified efficacy data are also needed to assist in the selection and use of appropriate vaccines (Meunier et al., 2015; Michel et al., 2023; Wang et al., 2024). 4.2 Equipment requirements, technical requirements, personnel training Whether the vaccination strategy can be smoothly implemented depends on the vaccination method and the breeding model. Vaccination in hatcheries, especially recombinant vaccines, is highly efficient and has a high vaccination rate, but it requires specialized equipment and professionally trained personnel to carry out in-egg vaccination or large-scale vaccination (Azzouguen et al., 2020; Wang et al., 2024). In contrast, when directly vaccinating poultry in farms, inactivated vaccines are generally used. This approach is more labor-intensive and time-consuming. Moreover, due to differences in vaccination operations, it is prone to cause inconsistent immune levels in poultry (Azzouguen et al., 2020; Michel et al., 2023). Large-scale vaccination through methods such as drinking water or spraying has been widely adopted because it is convenient to expand the vaccination range and can save labor costs. However, careful management is required to ensure that each poultry has uniform contact with and effective absorption of the vaccine (Ravikumar et al., 2022). Training the staff is crucial. This can reduce operational errors, ensure the correct use of vaccines, and maintain biosecurity, especially when using complex or new vaccine technologies (Wang et al., 2024; Bilal et al., 2025). 4.3 The economic benefits brought about by the reduction in vaccine costs and disease incidence rates Cost-benefit analysis shows that vaccination strategies for different poultry breeds and breeding types have the highest economic efficiency, and vaccination at hatcheries is usually more cost-effective than at breeding farms (Azzouguen et al., 2020). Vaccinating poultry can significantly reduce the prevalence and mortality rates, minimize related economic losses, and enhance the production efficiency and sustainability of the poultry farming industry (Ravikumar et al., 2022; Bilal et al., 2025). Although purchasing vaccines and equipment costs a lot of money at the beginning, the economic benefits brought about by the reduction of diseases, the improvement of poultry flock health, and the decrease in the demand for antibiotic use and poultry culling can offset these upfront costs. The most cost-effective vaccination strategy is to enable the entire poultry flock to obtain a high level of consistent immune protection, minimize difficulties in terms of manpower and transportation, and be able to be flexibly adjusted according to changes in disease threats (Azzouguen et al., 2020; Ravikumar et al., 2022; Bilal et al., 2025). 5 Challenges and Risks of Vaccination 5.1 Vaccine failure and antigen drift There are various reasons why poultry still fall ill after vaccination. For instance, the high concentration of maternal antibodies in poultry can inhibit the immune response triggered by vaccines, resulting in poultry being prone to infection even after vaccination (Pan et al., 2022; Li et al., 2024). In addition, improper vaccine management, such as the use of expired vaccines, poor storage conditions, or failure to administer vaccines at the prescribed time, can significantly reduce the efficacy of vaccines and thereby trigger disease epidemics (Cargill, 1999; Ma et al., 2021). Antigenic drift refers to the gradual accumulation of mutations in viral surface proteins, which poses a significant challenge to prevention and control efforts. Viruses such as avian influenza and infectious bronchitis can thereby evade the immune protection provided by existing vaccines. Once antigenic variation occurs, the protective effect of the vaccine will be partially or even completely lost. Therefore, continuous monitoring and regular updates of the vaccine strain are necessary to protect poultry all the time (Swayne et al., 2015; Jordan, 2017). 5.2 Biosecurity issues: risks of rising virulence and environmental spread of live vaccines Although live attenuated vaccines have a good prevention and control effect, there is a risk of virulence recovery, that is, the vaccine strain becomes pathogenic again, and then causes diseases in vaccinated or susceptible poultry
RkJQdWJsaXNoZXIy MjQ4ODYzNA==