Enhancing antibody positivity rates following foot-and-mouth disease vaccination in Korean pig farms

Abstract

Since the 2010 foot-and-mouth disease (FMD) outbreak, stringent biannual A+O vaccine protocols have been mandatory on pig farms since 2018, successfully maintaining an antibody positivity rate above 90% since 2021. However, 9.93% of farms report rates below 80%, highlighting ongoing vaccination challenges. This study analyzed 80 farms with subthreshold antibody positivity to determine causes of insufficient vaccine efficacy. The primary factor was vaccination frequency. Farms administering only the initial dose were 2.92 times more likely to have negative results than those giving both doses. Similarly, farms giving only the second dose faced a 2.10 times increased risk. Results showed antibody positivity rates of 10.04% for farms administering both doses, 6.44% for those administering only the second dose, and 4.67% for only the first. Analysis by vaccinator type indicated that foreign workers had a 1.18 times higher likelihood of negative results than farm owners, while external workers showed a 1.19 times higher likelihood of positive outcomes. Key issues included non-vaccination (43.4%), schedule non-adherence (13.1%), poor vaccine management (12.1%), and improper vaccination techniques (7.1%). Addressing these issues through enhanced farm owner and regulatory efforts is expected to significantly improve FMD control measures and increase the antibody positivity rates across domestic pig farms.