Britain begins trial of multi-variant COVID-19 vaccine booster

A phase one trial of a multi-variant COVID-19 vaccine booster drug has got underway among participants aged over 60 in the UK.

The trial, involving GRT-R910, has been launched by the US pharmaceutical company Gritstone in collaboration with the University of Manchester and Manchester University NHS Foundation Trust. It will explore the potential of the drug to boost the immune response of the first-generation COVID-19 vaccines to a wide array of variants of Sars-Cov-2, which cause COVID-19.

“We think GRT-R910 as a booster vaccination will elicit strong, durable and broad immune responses, which are likely to be critical in maintaining protection of this vulnerable elderly population who are particularly at risk of hospitalisation and death,” said Professor Andrew Ustianowski, Chief Investigator for the study, North Manchester General Hospital.

“We now know the immune response to the first-generation vaccines can wane, particularly in older people. Coupled with the prevalence of emerging variants, there is a clear need for continued vigilance to keep COVID-19 at bay,” he said.

Part of Gritstone’s CORAL programme, GRT-R910 is described as a self-amplifying mRNA second-generation SARS-CoV-2 vaccine – or SAM for short, which delivers antigens from both the spike and non-spike proteins.

“Our SAM COVID-19 vaccine is designed to drive robust CD8+ T cell responses, in addition to strong neutralising antibody responses, offering the promise of longer lasting immunity,” said Andrew Allen, MD, Co-Founder, President and Chief Executive Officer, Gritstone.

He added, “Since viral surface proteins like the spike protein are evolving and sometimes, partially evading vaccine-induced immunity, we designed GRT-R910 to have broad therapeutic potential against a wide array of SARS-CoV-2 variants by also delivering highly conserved viral proteins that may be less prone to genetic variation in the virus.

“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.”