From the Mayo Clinic: This is what multiple myeloma does to your immune system:
https://www.mayoclinic.org/diseases-conditions/multiple-myeloma/symptoms-causes/syc-20353378
Doctors know that myeloma begins with one abnormal plasma cell in your bone marrow — the soft, blood-producing tissue that fills in the center of most of your bones. The abnormal cell multiplies rapidly.
Because cancer cells don't mature and then die as normal cells do, they accumulate, eventually overwhelming the production of healthy cells. In the bone marrow, myeloma cells crowd out healthy blood cells, leading to fatigue and an inability to fight infections.
The myeloma cells continue trying to produce antibodies, as healthy plasma cells do, but the myeloma cells produce abnormal antibodies that the body can't use. Instead, the abnormal antibodies (monoclonal proteins, or M proteins) build up in the body
(end quote from Mayo Clinic)
NY Times says:
Colin L. Powell, whose immune system was weakened by treatment for multiple myeloma, died of complications of Covid-19 despite being “fully vaccinated,” his family said in a statement.
Peggy Cifrino, Mr. Powell’s longtime aide, said that he had been successfully treated for multiple myeloma, a cancer of white blood cells in the bone marrow.
The family’s statement did not provide further details about the complications or underlying health conditions. It said he was treated at Walter Reed National Medical Center. Other details about his health were not released, including whether he had received a booster shot, or when he had been vaccinated against the virus. He was 84.
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As if now, NYTimes knows he was fully vaxxed but they don't know how long ago.
As of now, NYTimes doesn't know if he ever received a booster shot.
My thoughts: Even if he was "successfully treated" for multiple myeloma, the family didn't say if his immune system had been fully restored to normal functioning.