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Progress Made Toward a Safer and More Affordable Polio Vaccine
A new era in polio vaccination is on the horizon, as researchers from the University of Leeds have made significant strides toward a more affordable and safer polio vaccine.
The breakthrough comes from extensive research focused on utilizing virus-like particles (VLPs) to create a novel polio vaccine. These VLPs are designed to replicate the outer protein shell of the poliovirus, but they are hollow within, eliminating any possibility of causing infection. Despite this, they effectively stimulate an immune response, presenting a promising alternative to existing vaccine options.
Leading the research project, Professor David Rowlands, an Emeritus Professor of Molecular Virology at the University of Leeds, has explored the efficacy of various expression systems—including yeast, insect, mammalian, and plant cells—for generating VLPs. Findings published in Nature Communications indicate that VLPs produced in yeast and insect cells demonstrate efficacy that meets or exceeds that of the traditional inactivated polio vaccine (IPV), which relies on using a killed version of the virus to provoke an immune response.
Professor Nicola Stonehouse, a senior author of the study and Chair in Molecular Biology at the University of Leeds School of Molecular and Cellular Biology, emphasized the importance of making vaccines accessible to all children. She stated, “The effectiveness of any vaccine is contingent upon its accessibility. Ensuring that vaccines like this can reach every child is critical in the fight against diseases such as polio. The development of VLPs stands to enhance vaccine equity significantly.”
“Thanks to ongoing research efforts, we are collaborating with commercial partners to bring forth the next generation of polio vaccines. While the timeline for widespread availability is still uncertain, we are progressing towards a future free from polio,” she added.
Current Polio Vaccination Landscape
The current IPV is relatively costly to produce, requiring stringent bio-containment measures to prevent accidental releases of live poliovirus, which could trigger outbreaks. In contrast, the VLPs being developed are non-infectious and do not necessitate such rigorous bio-safety protocols, making them a more appealing option for manufacturers.
The oral polio vaccine (OPV), which utilizes live but weakened poliovirus, remains a staple in vaccination efforts against polio. However, as the global community nears the eradication of remaining wild poliovirus strains, the reliance on OPV must be reevaluated due to the slight risk of vaccine-derived poliovirus variants that can arise, particularly in areas with low vaccination rates and poor sanitation.
Looking Ahead to Future Vaccines
Once all wild poliovirus strains are eradicated, the OPV will no longer be used. The IPV will then become the sole available vaccine, but due to high manufacturing costs, it remains prohibitive for many low-income countries. The production of non-infectious VLPs, which are proven to be more stable under varying temperatures thanks to genetic modifications, offers a more cost-effective production route. This could substantially enhance equitable vaccine distribution among affected populations.
Dr. Martin Eisenhawer, a focal point for the World Health Organization (WHO) in the development of Polio VLPs, acknowledged the significance of VLP technology as a potential game-changer for post-eradication scenarios. He noted, “The WHO has identified VLPs as a promising avenue for achieving a sustainable global supply of polio vaccines at low costs, particularly benefiting developing nations.”
Collaboration between researchers, vaccine manufacturers, and the Global Polio Eradication Initiative (GPEI) is vital in realizing this vision. Dr. Eisenhawer emphasized that advancements made through this research could ultimately ensure that polio remains eradicated, guaranteeing that no child suffers paralysis from poliovirus again.
The research initiative, with funding from the WHO, also involved esteemed institutions such as the University of Oxford, the Medicines and Healthcare products Regulatory Agency (MHRA), the John Innes Centre, The Pirbright Institute, the University of Florida, and the University of Reading. Advanced structural analysis was performed using a cryo-electron microscope at the Diamond Light Source.
VLPs are already employed effectively in vaccines for diseases such as hepatitis B and human papillomavirus (HPV). Researchers have been working diligently for over a decade to adapt this successful technology for the eradication of polio.
The next generation of polio vaccines is expected to be manufactured using yeast or insect cell systems, which have demonstrated efficacy in preclinical trials involving rats and mice. These methods are favored by manufacturers due to their lower costs and are integral to existing vaccine production.
Dr. Lee Sherry, one of the lead authors of the study during her tenure at the University of Leeds and now affiliated with the University of Glasgow, expressed optimism regarding the future of vaccine production. “Building on the success of VLPs in vaccines for hepatitis B and HPV-related diseases, it is thrilling to see industrial partners advancing this research as a safer vaccine production alternative in our journey toward a polio-free world.”
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