Watch CNBC's full interview with Pfizer CEO Albert Bourla on Covid vaccine rollout

The first doses of a Pfizer Covid-19 vaccine began shipping over the weekend, and the first vaccinations in the U.S. are set to take place Monday. The vaccine is a two-dose shot and roughly 95% effective in preventing the virus. Pfizer CEO Albert Bourla joined "Squawk Box" on Monday to discuss the rollout of the vaccine.