The news prompted a sell-off across the industry. In the US, shares in Pfizer and Moderna sank more than 5% in early trading, while UK-listed firms AstraZeneca and GSK dropped 2% or more. Russ Mould, investment director at AJ Bell, said the pick had “spooked” shareholders, despite questions about how the new administration might pursue its threats.

Critics believe Donald Trump's nominee to lead Health and Human Services poses a threat to the achievements of a science-based public health order painstakingly built since World War II.