Development of an Effective Single-Dose PCV2/CSFV Bivalent Subunit Vaccine Against Classical Swine Fever Virus and Porcine Circovirus Type 2

TL;DR

Researchers developed a single-dose vaccine that protects pigs against two diseases, PCV2 and CSFV, with strong immune responses and reduced viral loads.

Contribution

The study introduces a novel bivalent subunit vaccine combining PCV2 and CSFV antigens for effective and safe protection in pigs.

Findings

A single dose of the bivalent vaccine induced strong antibody responses against both PCV2 and CSFV.

Vaccinated pigs showed no clinical signs and had significantly reduced viral loads after challenge.

The vaccine is safe and effective in young pigs, offering a promising tool for disease control.

Abstract

Background/Objectives: Porcine Circovirus Type 2 (PCV2) impairs pigs’ immune systems and increases susceptibility to co-infections, including Classical Swine Fever (CSF), a highly contagious disease listed by the World Organisation for Animal Health (WOAH) as notifiable. Therefore, swine operations in CSF-endemic regions are encouraged to immunize piglets with both PCV2 and CSFV vaccinations. Currently, there is no commercially available bivalent vaccine for PCV2/CSFV. Methods: In this study, a total of twenty 4-week-old SPF pigs were administered our formulated PCV2/CSFV bivalent subunit vaccine, containing soluble CSFV-E2 (50 µg) and PCV2-ORF2 (100 µg) antigens with a porcine-specific CpG adjuvant. After 4 weeks of vaccination, all pigs were evaluated for efficacy against PCV2 and CSFV. Results: Pigs were only immunized once and showed significantly increased neutralizing or ELISA antibody titers against both viruses four weeks post-vaccination. After viral challenges, vaccinated pigs displayed no clinical signs or lesions and had markedly reduced CSFV and PCV2 viral loads in the serum and tissues compared to controls. Conclusions: These results demonstrate that a single dose of the PCV2/CSFV bivalent subunit vaccine is safe and effective in young pigs, induces strong antibody responses, and suppresses viral replication, making it a promising tool for swine disease control and cost-effective vaccination strategies.

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