The United Kingdom has launched phase one clinical trial of GRT-R910, the first multivariant Covid-19 booster vaccine. The trial will examine the potential of the vaccine to boost the immune response of the current Covid-19 vaccines against the various SARS-CoV-2 variants.

Gritstone, an American pharmaceutical company, has collaborated with The University of Manchester and Manchester University NHS Foundation Trust for the trial to investigate the dose, safety, tolerability, and immunogenicity of the vaccine.

The trial will recruit 20 participants, aged ≥60 years. Two doses of the vaccine will be administered at least 4 months after the second dose of the original vaccine taken. The findings of the trial may be released early next year.

The candidate vaccine is a self-amplifying mRNA (SAM) second generation vaccine and provides antigens from both the spike as well as non-spike proteins. Besides inducing neutralizing antibodies, the vaccine is also expected to generate CD8+ T cell response providing strong and durable immunity against the SARS-CoV-2 variants, which would be particularly beneficial in the vulnerable people (older people and the at-risk groups). It is hoped that GRT-R910 would reduce the number of doses needed or do away with the need for repeat vaccine administrations. As Andrew Allen, Co-Founder, President and Chief Executive Officer of Gritstone, said: “Our hypothesis is that a different vaccine, such as GRT-R910, might complement the primary immune response from pre-existing vaccination with a first generation COVID vaccine in such a way that it would provide more benefit than an additional dose of the same vaccine.”

(Sources: ETHealthworld, HealthEuropa, University of Manchester)