Vaccitech Plc, co-inventor of the Oxford University/AstraZeneca vaccine for Covid-19, has has made a regulatory filing in the US for an initial public offering of its shares on the Nasdaq market. The size of the offering had not been decided as of 11 April, but investors were reportedly looking for a valuation of around $700 million taking into account the wide distribution of the company’s Covid-19 vaccine and its portfolio of other prophylactic as well as therapeutic vaccines.