Clinical trials showed that the Pfizer-BioNTech COVID-19 vaccine has an efficacy of about 95%. The vaccine requires two doses to achieve full efficacy. It can also take several weeks for immunity to develop, during which people still remain vulnerable to COVID-19. Safety data from trials and monitoring of ongoing vaccination campaigns don’t show that vaccinated people are more likely to die from COVID-19. In fact, data from Israel indicates that the vaccine is effective at reducing the number of COVID-19 cases and hospitalizations.