The bubonic plague was a painful disease, with black buboes, or swellings, in the groin and armpits, which lasted up to a week. There was some chance of surviving if the buboes burst.
As of 2015, full retirement age is 67 if you were born after 1960. The amount you receive doesn't change because disability benefits were calculated based on what you would receive at retirement age. However, you may see an increase if Social Security provides a cost of living increase.
However, some older folks choose to apply for early retirement at age 62 or 63 rather than applying for disability. Even though this may seem an easier option, it can reduce the amount of benefits you are entitled to. You can get disability benefits up until full retirement age, which is 66 right now.