Oxford University To Begin Trial On Mixed Vaccines; GSK & CureVac Agree To Develop Vaccine Targeting New Variants
Oxford University is commencing the first trial investigating alternating the Pfizer/BioNTech and Oxford/AstraZeneca vaccines.

The world’s first mix-and-match COVID-19 vaccine trial, sponsored by Oxford University, is currently recruiting volunteers to investigate the efficacy of alternating between Pfizer/BioNTech and Oxford/AstraZeneca vaccines.

Meanwhile, the British GlaxoSmithKline and CureVac, a German pharmaceutical company, announced their new €150 million agreement to jointly develop a COVID-19 mRNA vaccine, attempting to address multiple emerging variants in one vaccine. 

The Oxford University is funded by the United Kingdom government’s Vaccines Taskforce, which is providing £7 million to the study. Participants will receive one dose of either the Oxford/AstraZeneca or the Pfizer/BioNTech vaccine, and then either a second dose of the same vaccine or a booster of the alternate vaccine within 12 weeks.

The trial follows upon a series of UK government decisions allowing for the second Pfizer dose to be delayed as a result of vaccine shortages, as well as the mixing and matching of vaccines on “extremely rare occasions.”

Trials Will Investigate If Combining Vaccines Could Potentially Enhance Immune Response

However, there is some emerging evidence suggesting that the mixing and matching of vaccines – which rely upon different technologies – could also prove beneficial in terms of generating a stronger immune response, said Britain’s Deputy Chief Medical Officer, Jonathan Van-Tam, who will be the senior responsible officer for the study. 

“It is also even possible that by combining vaccines the immune response could be enhanced, giving even higher antibody levels that last longer. Unless this is evaluated in a clinical trial, we just won’t know,” said Van-Tam.

Data gathered in the trial is expected to help policy-makers make decisions to increase the flexibility of vaccination programs, which continues to be of high importance to the UK, where COVID-19 infections remain high, worsened by the spread of the highly transmissible variant, B.1.1.7.

“If we do show that these vaccines can be used interchangeably in the same schedule this will greatly increase the flexibility of vaccine delivery, and could provide clues as to how to increase the breadth of protection against new virus strains,” said Matthew Snape, who will be the principal investigator in the trial. 

The trial will include over 800 participants aged 50 and above and will last 13 months. The four vaccine combinations will be evaluated on two dosing schedules, at a four week interval and a 12 week interval. 

“As we roll out vaccinations in the UK, we have the opportunity to look at how to get the most out of the vaccines available to us,” said Maheshi Ramasamy, senior clinical researcher and investigator of the trial. “This innovative study looks at whether using different combinations of two currently approved vaccines is a good alternative to the standard schedule. We will also be looking at the impact of the interval between doses on immune responses.”

“This study will give us greater insight into how we can use vaccines to stay on top of this nasty disease,” said Van-Tam.

GSK and CureVac To Develop Multi-Variant COVID-19 Vaccine

As for the GSK and CureVac research into a robust vaccine against variants, the development project aims to have vaccines available in 2022, if the safety and efficacy data is strong. 

Such a product potentially could serve as an initial vaccination or as a booster if immunity from previous jabs reduces over time, said Emma Walmsley, CEO of GSK, in a press release

“We believe that next generation vaccines will be crucial in the continued fight against COVID-19. This new collaboration builds on our existing relationship with CureVac and means that together, we will combine our scientific expertise in mRNA and vaccine development to advance and accelerate the development of new COVID-19 vaccine candidates,” said Walmsley. 

The company will explore a COVID-19 vaccine targeting several SARS-CoV2 variants; but the collaboration will also look into developing a novel mRNA vaccine to protect against multiple respiratory viruses, she said. 

“They’re trying to develop ‘universal vaccines,’ i.e. vaccines targeting multiple respiratory viruses/coronaviruses. That would be a big contribution to the world, but it’s a big ask. The world has tried for many years to get universal flu vaccines, but they’re technically hard to develop. So this is a high-risk, high-reward strategy,” said Adam Barker, healthcare analyst at Shore Capital, in an interview with the Guardian

The collaboration will also include GSK assisting in manufacturing up to 100 million doses of CureVac’s COVID-19 vaccine candidate in 2021. The mRNA candidate is currently in Phase 2b/3 clinical trial; Like Moderna’s mRNA vaccine, it is designed to be stored at standard 2-8°C vaccine storage conditions.

Image Credits: BioNTech, University of Oxford.

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