Germany's CureVac announced on Wednesday 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 and Moderna.

The poor outcome, AFP reported, had been expected after disappointing interim results were released earlier this month.

CureVac said its vaccine did slightly better among people aged 18 to 60 than among older age groups, with efficacy climbing to 53pc.

The company said its trial was complicated by the prevalence of numerous coronavirus variants.