Pfizer’s chief executive sold shares in the company worth $5.6m (£4.2m) on the day the drugmaker announced that its Covid-19 vaccine was more than 90% effective in protecting people from transmission of the virus, triggering a surge in the company’s stock. Albert Bourla sold 132,508 shares at $41.94 a share, equivalent to 62% of his shareholding in Pfizer, according to filings with the US Securities and Exchange Commission (SEC). This is close to the $41.99 peak the share price hit on Monday. Pfizer said that the shares were sold via an automated system after they hit a certain price, under a plan set up in August. Pfizer shares opened at $41.94 on Monday morning after the announcement, up 15% from Friday’s close of $36.40, and finished 7.7% higher at $39.20. Since then, they have fallen back to $38.40. Global stock markets reached record highs that day on hopes that the vaccine could help bring an end to a pandemic that has killed more than a million people. The company said: “The sale of these shares is part of Dr Bourla’s personal financial planning and a pre-established (10b5-1) plan, which allows, under SEC rules, major shareholders and insiders of exchange-listed corporations to trade a predetermined number of shares at a predetermined time.” The vaccine performed much better than most experts had hoped and does not have serious side-effects, according to the interim analysis by Pfizer and its German development partner, BioNTech. Bourla hailed it as “the greatest medical advance in the last 100 years”. Pfizer is working on turning the vaccine into a powder formula. In its current form, the vaccine has to be stored at -70C, which poses significant distribution challenges, especially for lower-income countries. It is the first coronavirus vaccine that has been shown to work, but a number of others are in development, and final data from global clinical trials is expected from the UK’s AstraZeneca, in partnership with Oxford University, and the US biotech Moderna before the end of the year. Pfizer did not participate in Donald Trump’s Operation Warp Speed drug development programme and used $2bn of its own money to develop the vaccine, which was invented by BioNTech. The vaccine could generate nearly $13bn in global sales next year, according to analysts at Morgan Stanley, which would be split evenly between the two companies.