Anti-Vax world is obsessed with the fact that the CEO of Pfizer sold stock the day the vaccine was announced. If you hear this and feel like you need to explain it, here's what happened:

CEOs almost never decide to sell stock in their own company. They know so much about the internal goings on at their companies, that any decision to sell stock could be seen as insider trading.

So, CEOs (and other executives) hire external companies that set sell-schedules.

These schedules automatically sell stock either at specific times, or when the stock hits a particular price. In this case, when the vaccine was announced, the stock price spiked, which triggered a previously set sale of stock.

So no, the CEO of Pfizer did not decide to dump stock because he knows the vaccine is...bad or something. The release of the vaccine caused the stock price to increase which met a previously defined target for a stock sale.