June 7, 2023

 

US scientists make progress towards long-lasting universal swine flu vaccine

A breakthrough long-term experiment involving live swine has brought Nebraska scientists closer to developing a safe, long-lasting, and potentially universal vaccine against swine flu, Phys.org reported.

 

The implications of this research extend beyond the pork industry as pigs act as "mixing vessels," where different strains of swine and bird influenza can reconfigure and become transmissible to humans.

 

The study, recently published in Frontiers in Immunology, underscores the need for more effective vaccination strategies in vulnerable swine populations.

 

Erika Petro-Turnquist, a doctoral student and lead author of the study, said that there is a significant role swine play in the evolution and transmission of potential pandemic strains of influenza, as well as the economic impact of swine flu viruses.

 

The Nebraska Centre for Virology, led by Eric Weaver, an associate professor, spearheaded the research effort using Epigraph, a data-based computer technique co-developed by Bette Korber and James Theiler of Los Alamos National Laboratory.

 

Epigraph enables scientists to analyse numerous amino acid sequences among hundreds of flu virus variants to create a vaccine "cocktail" of the three most common epitopes that stimulate the immune system's response. This approach paves the way for a universal flu vaccine, which aims to be at least 75% effective, protect against multiple types of influenza viruses for at least one year, and be suitable for all age groups, as defined by the National Institutes of Health.

 

Currently, pork producers rely on commercially available vaccines derived from whole inactivated viruses and weakened live viruses to manage swine flu. But the rapid evolution of swine influenza poses challenges, making custom-made vaccines for specific herds costly, time-consuming, and less effective.

 

The Epigraph algorithm and adenovirus vector delivery system used in the study offer potential solutions to enhance vaccine effectiveness and durability.

 

In a longitudinal study comparing the onset and duration of an adenovirus-vectored vaccine with a whole inactive virus vaccine, researchers observed 15 Yorkshire cross-bred female swine over approximately six months, reflecting the typical lifespan of a market hog. The swine were divided into three groups: one receiving the Epigraph vaccine, another receiving a commercial whole inactive virus vaccine, and a control group receiving a saline solution. Antibody levels and T-cell responses were measured regularly, and at six months of age, the swine were exposed to a strain of swine flu divergent from those represented in the vaccine.

 

The swine that received the Epigraph vaccine demonstrated faster and more sustained antibody and T-cell responses. When exposed to the swine flu virus, these swine exhibited superior protection, with less viral shedding, fewer infection symptoms, and stronger immune system responses.

 

The vaccine's efficacy remained robust throughout the pigs' growth, from weighing around five pounds during vaccination to over 400 pounds at the study's end. Moving forward, Weaver's team plans to conduct larger studies and explore potential commercial partnerships to bring the vaccine to market.

 

-      Phys.org