There are a lot of questions on the COVID vaccine from both employer and employees. Although this publication is UK based, I found their Q&A quite good.
The first takeaway…
How effective is the vaccine?
About 95 per cent. The phase 3 trials of the Pfizer/BioNTech vaccine involved 42,000 people, about half of whom got the experimental vaccine and the rest a placebo. In total, 170 people fell ill with covid-19. Only eight of them were in the vaccine group; 162 had received the placebo. So around 5 per cent of cases were in the vaccine group, which is where the 95 per cent figure comes from. That is a very healthy number: the World Health Organization (WHO) has said it would be happy with 50 per cent.
Read more: https://www.newscientist.com/article/2261805-everything-you-need-to-know-about-the-pfizer-biontech-covid-19-vaccine/#ixzz6gdNAs6Ui
As a note, the influenza vaccine in Canada is about 58% effect