On Sept. 30, 2025, a team of researchers involving Roslin Institute scientists tested a solid dose of a modified live vaccine (MLV), delivered using a needle-free technology developed by the company aVaxziPen which injects the vaccine under the surface of the skin, combined with a nasal boost using an inactivated vaccine.

While the nasal boost failed to enhance immunity in pigs, the solid dose vaccine was shown to provide neutralising antibody responses and strong protection against infection, which was comparable to protection attained by conventional needle-and-syringe vaccination. 

The study also showed the solid dose PRRSV vaccine to be less stable than expected, leading to evaluation at a lower dose than typically used. However, both solid and liquid formulations provided a high level of protection, suggesting that lower vaccine doses may be effective without compromising efficacy.

A needle-free, solid dose vaccine can protect pigs against one of the most costly diseases in global pig farming, research shows. The development in preventing Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) marks the first time that needle-free solid-dose vaccine technology has been shown to work in any species.

The approach could help mitigate losses from PRRSV, which are estimated to exceed US$660 million annually in the US alone, and meet a need for effective vaccines. 

The study, published in Vaccine, was led by the Pirbright Institute and involved expertise from the Moredun Research Institute, animal health company Zoetis, Scotland’s Rural College (SRUC), and aVaxziPen.

The findings build on previous work by Pirbright and aVaxziPen on solid dose PRRSV vaccines and complement studies by the Roslin Institute on intranasal vaccine delivery using jet injectors.