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Wessex led study trialling a plant-based COVID-19 vaccine shows positive results

Wessex led COVID-19 vaccine study positive results

Results from a study of the world's first plant-based COVID-19 vaccine by Medicago GSK have found it is 75.3% effective against preventing COVID-19 of any severity (from the Delta variant).

Led by Dr Chrissie Jones from the University of Southampton, this study recruited almost 300 participants at 11 sites across the UK, including the Dorset Research Hub based at University Hospitals Dorset NHS Foundation Trust. The study was delivered with support from staff across the Wessex region, including the Portsmouth Research Hub, part of Portsmouth University Hospitals NHS Trust. 

A total of 24,000 volunteers across six countries were involved and no related serious adverse events were reported, with reactogenicity (expected vaccine reactions) generally mild to moderate. The Omicron variant was not circulating during the study.

The Phase 3 placebo-controlled efficacy study assessed Medicago’s plant-based COVID-19 vaccine candidate in combination with GSK’s pandemic adjuvant (a vaccine ingredient used to create a stronger immune response), in adults 18 years old and above.

The 293 participants recruited in the UK were vaccinated between April and June 2021, while the UK deployed vaccine rollout was taking place, which impacted on the final number of volunteers. The first participant in Europe was recruited at the Swansea Bay University Local Health Board site.

Dr Chrissie Jones, Associate Professor in Paediatric Infectious Diseases at University of Southampton and Chief Investigator for the study, said:

"We are very grateful for the contributions of participants on the Medicago study, which have helped to identify another effective vaccine to help fight coronavirus.

“The fact that the vaccine candidate from Medicago and GSK is shown to produce a robust immune response, is exciting news as this plant-based platform can produce new vaccines. This could help support countries around the world which are yet to vaccinate their population, as it may be easier to manufacture and scale up, aiding low- middle-income countries.”

Yosuke Kimura, Chief Scientific Officer at Medicago, said:

“I am pleased to see our vaccine candidate moving forward and bringing to the world the first plant-based vaccine against COVID-19, diversifying the pool of vaccines available to help improve public health and protect more people.”

Prof Andrew Ustianowski, National Clinical Lead for the UK NIHR COVID Vaccine Research Programme, said:

“We are pleased to see this latest vaccine study findings, which have been supported by research teams and volunteers across the UK.

“The NIHR and our UK research community partners, along with the support of participants, continue to help to discover safe and effective vaccines to fight COVID-19. Positive study results such as this demonstrate that there is still a lot to learn and room for innovation within vaccine research."

Medicago will imminently seek regulatory approval from Health Canada as part of its rolling submission. The vaccine candidate is not approved yet by any regulatory authorities.

Full results of the Phase 3 study will be released in a peer-reviewed publication as soon as possible.