Barry Norris, chief executive of Argonaut Capital, has been unabashedly vocal about his pessimism about a potential Covid-19 vaccine. He shorted pharma companies including Moderna — which is developing an inoculation against the virus — back in August.

Other market participants haven’t shared his bearish views. Pfizer and BioNTech were first out of the gate with positive vaccine news — saying in early November that their coronavirus jab showed 90% efficacy and could be rolled out this year. It prompted a massive stock market rally, with pubs, restaurants, travel companies and finance firms among those to post sharp share price increases.