The French healthcare group will instead focus on efforts with British partner GlaxoSmithKline to bring a Covid-19 vaccine candidate to market based on the more conventional protein-based approach, where mass trials are ongoing.

The decision to drop clinical development of the mRNA shot, acquired as part of its takeover of Translate Bio, came despite positive Phase I and II study interim results announced today where participants’ blood readings showed a strong immune reaction.

But Sanofi said the read-out encouraged it only to pursue the technology as a potential vaccine against influenza and other diseases, giving up on the area of Covid-19 because of the strong market presence of the two approved mRNA shots.

“These results will clearly help inform the path forward for our mRNA development programmes,” said Jean-Francois Toussaint, global head of research and development at Sanofi Pasteur.