Plans for large-scale testing of a UK-developed experimental coronavirus vaccine are being pulled after the success of drugs already in the market.
Scientists at Imperial College London (ICL) announced they would instead use the technology behind the vaccine to target coronavirus mutations.
"Although our first generation Covid-19 vaccine candidate is showing promise in early clinical development, the broader situation has changed with the rapid roll-out of approved vaccines," Prof Robin Shattock at the department of medicine said.
“It is not the right time to start a new efficacy trial for a further vaccine in the UK, with the emphasis rightly placed on mass vaccination in response to the rapid spread of the new variant.”
The vaccines developed so far appear to be effective against mutations that appeared in the last few weeks, including the UK, South African and Brazilian variants.
However, there are fears – among epidemiologists and expressed at the World Economic Forum this week – that one vaccine may be less effective against the South African variant, and there is also the greater fear that the next mutation will be immune to the current vaccines.
Mass testing of the ICL vaccine had been planned for later this year, but with a number of drugs now on the market or close to being approved, the team decided to move on to watching for developing mutations.
The ICL vaccine is similar in design to the Moderna and Pfizer-BioNTech drugs, using self-amplifying RNA technology to target the Sars-Cov-2 protein.
"We want our technology to have the greatest impact. That means focusing our UK efforts on developing self-amplifying RNA technology to adapt to new variants, to boost other vaccines and to be deployed against future pandemic threats," Prof Shattock said.
"We want to develop Imperial's technology as a safety net to catch escape mutations, reach variants that other vaccines may not and meet potential needs for annual booster vaccinations."
The RNA technology could be used to target variants as they emerge, ICL said, and that could make it a useful ingredient in second generation vaccines.
Prof Alice Gast, president of ICL, said: "Imperial's self-amplifying RNA vaccine has much to offer in the fight against coronavirus and other diseases.
“This exciting technology will help accelerate future vaccine production, providing the agility to defend against viral mutations, and protect current and future generations from pandemics.”