A trivalent enteric coronaviruses inactivated vaccine provides effective protection against PEDV, TGEV, and PDCoV

Porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and porcine deltacoronavirus (PDCoV) are three major coronaviruses responsible for severe diarrhea and mortality in piglets. Co-infections of these pathogens are frequently present in clinical cases, which aggravate the clinical symptoms and cause substantial economic losses in the swine industry. Currently, no commercially available vaccine has broad-spectrum protective efficacy against all three viruses. In this study, we developed a trivalent inactivated vaccine targeting PEDV, TGEV, and PDCoV, to evaluate its immune protection, suckling piglets were intramuscular immunized with trivalent inactivated vaccine using prime-boost immunization. Neutralizing antibody assay showed that all vaccinated piglets achieved titers of 1:64 or higher at 7 day-post-boost immunization. The pigs were orally challenged with PEDV, TGEV, and PDCoV respectively. More severe and prolonged diarrhea, higher levels of viral shedding, substantial intestinal villus atrophy, and positive straining of viral antigens in ileum were detected in challenge control groups, while the trivalent inactivated vaccine groups exhibited significantly milder diarrhea symptom, lower levels of viral shedding, minor intestinal villi damage and minimal straining of viral antigens. These results demonstrated that the PEDV-TGEV-PDCoV trivalent inactivated vaccine provide effective protection in pigs against all three enteric coronaviruses.