Moderna has said up to 1.7bn people at high risk from Covid-19 would benefit from annual booster shots, as it prioritises developing a new jab targeting the fast-spreading Omicron variant to be released in the autumn.

The US drugmaker said demand for a bivalent booster could lift sales of its Covid jab in the second half of the year. The booster works by stimulating an immune response against two different antigens, which in this case would be the original wild type strain of Covid-19 as well as the mutations present in the Omicron variant.

Moderna maintained its forecast for $21bn in vaccine sales this year despite evidence of a slowdown in global demand for inoculations and said its Omicron booster was its lead candidate out of three new bivalent jabs under evaluation. First data from clinical trials of the Omicron booster candidate would be available in June, the company added.