Efficacy of Porcine Epidemic Diarrhea Vaccines: A Systematic Review and Meta-Analysis

Porcine epidemic diarrhea (PED) is a devastating disease that causes considerable economic damage to the global pig industry. Although the causative agent, the porcine epidemic diarrhea virus (PEDV), was identified about a half century ago, there is still much debate on the preventive measures against the disease, especially regarding the PED vaccine. Recent reports on PEDV variants make the vaccination for PEDV more confusing. Therefore, we systematically reviewed published articles on PED and vaccines against the disease and performed a meta-analysis of vaccine efficacy based on the clinical signs, fecal score and survival rates. A total of 299 articles on the efficacy of PED vaccines were found online, and 21 articles were selected that fulfilled all the criteria. A meta-analysis was performed on the 21 articles based on the fecal scores and survival rates. This analysis showed the efficacy of PED vaccines, and no significant differences in the efficacy depending on vaccine type (killed vs. live) or administration route (intramuscular vs. oral) were found. The results from our study suggest that any vaccination against PED is a useful strategy to control the disease regardless of the type of vaccine and administration route.