64% was the test result, based on a single jab, and all it measured was whether or not you got the virus, based on a small sample. Real world data has a much larger sample and shows 76% efficiency in preventing the virus with a single jab, and further shows that the 24% who got it, get it much less seriously, and that transmission is much reduced as well. Tests and the results of real world data show that the second jab results in 95%+ protection from getting the disease and 100% (or as near as any test can be) protection from death.
This is the absolute key.......even if you're one of the unlucky 20 or 30-odd percent who still catch it, you're very, very unlikely to end up in hospital and even less likely dead.