[david38]

We have this already. As a species we are susceptible to many diseases which we have to take vaccines for, every generation.

[pfannkuchen]

I don't think susceptibility to viral diseases like measles is typically regarded as a genetic defect, is it? Any more than being flammable is a genetic defect, anyway.

[roywiggins]

There are a few people who are genetically immune to HIV, but it's quite rare. Whether everyone else is therefore genetically deficient is sort of a matter of perspective, I suppose.

https://en.m.wikipedia.org/wiki/Innate_resistance_to_HIV