That doesn't really engage with "there's easier ways to attack" or "and this tech is currently hard enough this is not a realistic attack".

That said:

What if a different group near simultaneously makes one targeting people with no copies of the HbS/HbA gene?

(One copy: resist malaria; two copies: sickle cell anaemia)

In case anyone wonder what op means - lyfgenia is a virus for treating sickle cell, a disease thats more common among black population.