A new milestone for our portfolio company ViroVet. Fantastic results to work further towards an improvement of animal health and a more sustainable animal production.

ViroVet scores with PRRS vaccine based on PLLAV technology

LEUVEN, Belgium, March 27th, 2023 – ViroVet NV, a leading Belgian biopharmaceutical company active in the development of innovative vaccines and antiviral drugs for livestock, proudly announces the development of a porcine reproductive and respiratory syndrome (PRRS) vaccine based on the PLLAV (Plasmid Launched Live Attenuated Virus) vaccine technology that provides solid protection against the disease.

ViroVet is a pioneer in the development of new and innovative vaccines based on a unique and patented technology platform originating from the Rega Institute for Medical Research of the University of Leuven (KU Leuven). This technology platform allows vaccines to be designed and produced faster and more cost-effectively.

With the support of VLAIO, ViroVet completed a challenge study in weaner pigs with the new PLLAV-based vaccine for PRRS. This study successfully confirmed that vaccine doses in the microgram DNA range elicit strong antibody responses against the PRRS virus. Moreover, interferon-gamma responses were also demonstrated, confirming the potential of the PLLAV vaccine to activate cell-mediated immunity. More importantly, it was demonstrated for the first time that the vaccine provides excellent protection against PRRS disease. Pigs vaccinated with the new PLLAV vaccine showed no clinical signs and had significantly fewer virus particles in their blood than pigs vaccinated with an existing commercial vaccine.


Erwin Blomsma, CEO of ViroVet, states: “The results of this successful PRRS study came just in time to present them at an annual international animal health congress in London. The results were well received, and suddenly we are in the spotlight of all major animal health companies. It looks like it’s going to be a special year for ViroVet.”


Nesya Goris, CDO of ViroVet, adds: “It remains impressive that administering a small amount of naked DNA elicits such good protection against a PRRS viral infection in pigs. PRRS still causes significant losses to the pig industry every year, and this vaccine will help to reduce the impact of this disease in the near future.”


George Gunn, Chairman of the Board: “The design of this latest version of the PRRS vaccine began in September 2022. To go from a design in the laboratory to a successful proof-of-concept in pigs in less than 6 months demonstrates the potential of this new and disruptive PLLAV technology.”