Please, somebody help me with my maths here:

The Pfizer vaccine trial included nearly 44,000 people. Half getting their vaccine, half getting a placebo. In total, from the 44,000 people, 170 were later recorded as having become infected with Covid19. 162 of them were in the placebo group, 8 of them in the vaccine group.

The vaccine is therefore credited with preventing 162 cases of Covid19or 95%.

Suppose they used a vaccine that did nothing. You would expect that 50% would be in the vaccine group and 50% in the placebo group. Would they then claim their vaccine was 50% effective?