Germany's CureVac has said that final trial results showed its coronavirus vaccine had an efficacy rate of just 48 per cent, far lower than those developed by mRNA rivals BioNTech/Pfizer and Moderna.

The outcome had been expected after poor interim data was released earlier this month, AFP reports.

The company in part blamed “the unprecedented context of 15 strains circulating” among the trial volunteers, as well as varying responses across age groups.

The Covid vaccines developed by Germany's BioNTech in partnership with US giant Pfizer and by US firm Moderna — based on the same novel messenger RNA technology — were approved earlier on in the pandemic after showing around 95pc efficacy.