Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHP) are both important and common pathogens in the pig industry. Both pathogens are major contributors to the porcine respiratory disease complex and serve to potentiate other bacterial infections such as Actinobacillus pleuropneumonia. This study aims to evaluate the efficacy of a ready-to-use bivalent PCV2 and MHP vaccine in the field under naturally PCV2-infected farms against existing monovalent options. We evaluated PCV2 viremia, PCV2 antibodies, and lung lesion scores in slaughtered pigs in our study across four farms in Taiwan. Our results found that in two out of four farms, the piglets vaccinated with Porcilis^® PCV M Hyo had superior whole-life PCV2 viremia reduction compared to the existing vaccination program on farms. In the lung lesion scoring, the Porcilis^® PCV M Hyo group had significantly lower Actinobacillus pleuropneumonia-type lesions in pigs than in the competitor group in two out of three farms evaluated. In this field trial, Porcilis^® PCV M Hyo proved to be efficacious in protecting piglets against both PCV2 viremia and the impact of MHP secondary infection, in the context of a reduction in viremia and reduced APP-like lesions found at slaughter.

Porcine epidemic diarrhea virus (PEDV) is an economically important pathogen of swine, causing severe diarrhea in neonates with high morbidity and mortality. Vaccination is a key strategy for PEDV control, but optimizing regimens based on herd status is essential for improving immunity and protection. This study evaluated immune responses to different vaccination protocols using a PED replicon vaccine (PED-RP) in Thai swine farms with varying PED statuses. Two field trials were conducted: Experiment 1 (n = 120) on a PED-negative farm used a killed vaccine followed by PED-RP, while Experiment 2 (n = 42) on a PED-positive farm used a modified-live vaccine (MLV) followed by PED-RP. In Experiment 1, gilts boosted with PED-RP during gestation showed significantly higher colostrum IgA levels compared to those receiving two doses of the killed vaccine. In Experiment 2, priming with MLV followed by PED-RP resulted in increased neutralizing antibody titers and seropositivity, outperforming the MLV-only regimen after acclimatization. These findings suggest that using PED-RP as a booster can enhance serum and lactogenic immunity, providing a promising strategy for improving immune responses in both PED-negative and PED-positive herds. The study highlights the importance of tailored vaccination strategies to optimize herd immunity and protect piglets from PEDV.

Background/Objectives: Porcine circovirus type 2 (PCV2) has a major impact on swine productivity. Vaccines are used to aid in control and mitigate production losses. We investigated the protection provided by an intradermal PCV2 vaccine against a field strain in Taiwan. Methods: We conducted a safety and efficacy study. In the safety study, four Specific Pathogen Free (SPF) piglets were enrolled in the study. One was selected as the control and left unvaccinated, one was selected to be intradermally vaccinated with five times the standard dose (1 mL, Porcilis^® PCV ID), and the other two were vaccinated with two times the standard dose (0.4 mL, Porcilis^® PCV ID). All animals were observed for 3 weeks for adverse events post-vaccination. In the efficacy study, twelve SPF pigs negative for the PCV2 antibody were randomly divided into two groups. The first group of six pigs was vaccinated (Porcilis PCV ID, 0.2 mL) intradermally at 3 weeks of age. The second group of six pigs was sham vaccinated with 0.2 mL of normal saline. At 7 weeks of age, all pigs were challenged with the PCV2 strain CYC08 (1 × 10⁵ TCID₅₀/mL) by nasal and intramuscular injection. Clinical monitoring of body temperature and mortality was conducted daily. At 11 weeks of age, all animals were sacrificed for histopathological analysis. Results: No adverse events were reported in the safety study. In the efficacy study, the vaccinated animals had statistically improved results in the following areas post-challenge: body temperature rise, viremia, virus shedding, mortality, tissue histopathological and microscopic scores. Conclusions: The study results support that a one-dose PCV2 vaccine administered intradermally with a needle-free injector is safe and provides protection when challenged with a field PCV2 strain.