Colin Powell, 84, died Monday morning due to complications from Covid-19. Powell was fully vaccinated against the virus, his family said in a statement. Powell was elderly, a known risk for severe Covid, and suffered from multiple myeloma, a blood cancer that studies show can make the shots less effective. A study published in late July found that only 45% of patients with active multiple myeloma developed an "adequate" immune response after getting vaccinated with either the Pfizer-BioNTech or Moderna vaccines. Just 22% of patients in the study had a "partial" response.... Offit said fully vaccinated people with weak immune...