Vaccines will not inoculate investors against the danger of an ‘epic bubble’

Markets have been on a dazzling run since Pfizer's trial results. Now there is reason to worry that things are going too far

Six months ago exactly - on 9 November last year - Pfizer unveiled interim data from trials of a vaccine candidate known as BNT162b2, developed in partnership with German firm BioNTech. The numbers were far better than expected: 90% efficacy in preventing Covid.

Today is a great day for science and humanity," declared Albert Bourla, the company's chief executive, a judgment that clearly still stands half a year later. Even as the pandemic still rages - appallingly in India, Brazil and many other places - the arrival of effective vaccines has been a turning point in the crisis.