Moderna Inc has said it expects Covid-19 vaccine sales of $18.4 billion this year, above the $15bn in sales forecast by Pfizer Inc for the only other vaccine authorised for emergency use in the United States so far.

“2020 demonstrated the power of harnessing mRNA to make medicines,” Chief Executive Officer Stéphane Bancel said in a statement. “I believe that 2021 will be an inflection year for Moderna.”

Moderna expects cost of sales to be about 20 per cent of product sales in 2021, well above the 4pc it recorded a year earlier.