A few lucky individuals won't ever contract AIDS: they're genetically immune. (discovermagazine.com)
Life expectancy then was a mere 40 years on average, with a few lucky individuals making it to 75 or more, though they would likely have succumbed to the first harsh illness they faced. (newscientist.com)
In a bacterial population exposed to a killer drug, a few lucky individuals might have a genetic mutation that kept them alive. (scientificamerican.com)