A needle-free, solid-dose vaccine can protect pigs against one of the most costly and devastating diseases in global pork production, reveals new research at the Roslin Institute.
This marks the first time that needle-free, solid-dose vaccine technology has been shown to work in any species, the Roslin Institute says in a release. This discovery was made in a “prime and pull” immunization strategy study focused on preventing porcine reproductive and respiratory syndrome virus (PRRSV).
Despite almost four decades of research, modified live vaccines (MLV) remain critical for PRRS control, especially in unstable herds, the researchers say.
“It is recognized that they [PRRS MLV vaccines] outperform inactivated vaccines in terms of efficacy,” the study says. “As such, PRRSV MLV vaccines cannot considered to be perfect, as they are unable to provide sterile immunity and can mutate and recombine with field strains.”
In addition, researchers note practical issues of storage and administration on-farm.
“It’s a step forward, not just for pig health, but for vaccine delivery technology more broadly — including for potential future use in humans,” says Simon Graham, a professor at Pirbright Institute.
No Needles Needed
Roslin Institute scientists were part of a team of researchers who tested a solid dose of an MLV, delivered using a needle-free technology developed by the company aVaxziPen. The technology 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 neutralizing antibody responses and strong protection against infection, which was comparable to protection attained by conventional needle-and-syringe vaccination,” the release says.
The solid-dose PRRSV vaccine ended up being less stable than expected, which resulted in evaluation at a lower dose than typically used. However, both solid and liquid formulations provided a high level of protection, the Roslin Institute says. This suggests lower vaccine doses may be effective without compromising efficacy.
“Solid-dose vaccines offer the potential to transform vaccine delivery, improve animal welfare and eliminate needle related risks for staff,” adds Robin Cohen, CEO at aVaxziPen.
Risk Reduction
The development of needle-free vaccination could lower the risk of spreading diseases via reused needles, improve animal welfare and potentially address needle-phobia in people.
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.
This study builds on previous work Pirbright and aVaxziPen conducted on solid-dose PRRSV vaccines and complements studies by the Roslin Institute on intranasal vaccine delivery using jet injectors.
“This is an encouraging development towards managing one of the pig industry’s most harmful infectious diseases,” says Christine Tait-Burkard with the Roslin Institute.
Researchers believe this approach could help mitigate losses from PRRSV, which are estimated to exceed $660 million annually in the U.S. alone.
Editor’s Note: The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council and it is part of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies.
