A new study using pigs shows that inhaled vaccines could potentially reduce viral transmission and improve vaccine efficiency, The Pirbright Institute reports.
“This is an important step toward human research,” Pirbright said in a release. “Interest in administering vaccines mucosally, rather than by intramuscular injections, has been growing since the SARS-CoV-2 pandemic was declared in 2020.”
Scientists from The Pirbright Institute and the University of Oxford used pigs as a model to explore immune system responses to mucosally-administered flu vaccines, which target viruses at the point of entry.
“Comprehensive measurement of immune responses in human lungs is not possible,” the researchers explain in a release.
To overcome this challenge, the researchers used pigs—whose respiratory tract is anatomically and functionally similar to that of humans—as a model to define key immune responses. Samples collected from both the lungs and blood of vaccinated pigs, aided by mathematical modelling, showed that lung responses can be predicted from blood tests, making it easier to assess vaccine effectiveness in humans, the release said.
“To bring future vaccines to market, it is critical to define the correlates of protection—markers that can reliably predict the effectiveness of the vaccine, in humans,” Dr. Simon Gubbins, Head of Transmission Biology at The Pirbright Institute, said in a release. “Our study explored potential assays, sampling times and sample types (such as blood and lung samples) which could define correlates of protection in humans.”
The findings of this study, published in Frontiers in Immunology have far-reaching implications for the future development of mucosally-administered vaccines in clinical trials, Pirbright said. The pig model’s ability to closely mimic human immune responses to respiratory infections make it an ideal platform for testing vaccine efficacy.
“The research found that immune responses in the blood could reliably reflect those in the lungs, thus offering a practical way to assess the effectiveness of vaccines targeting the respiratory system,” Professor Dame Sarah Gilbert, Saïd Professor of Vaccinology, Pandemic Sciences Institute at the University of Oxford, said in a release. “The findings provide critical insights into how immune responses can be measured from easily accessible blood samples and are a foundation for future testing of mucosally administered vaccines in clinical trials.”
Pirbright said this research defining effective biomarkers for mucosal vaccine efficacy and identifying the best ways to monitor and measure immune protection lays the foundation for next generation vaccines. These vaccines could someday offer improved protection against respiratory viruses and benefit public health worldwide.
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